From ea74e4f7add23dbf946733812adff32e17eb371c Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:06:18 +0900
Subject: [PATCH 01/65] wip: failed attempt

---
 .../vitest/src/node/pools/applyBlobLabel.ts   | 22 ++++++++++
 packages/vitest/src/node/pools/rpc.ts         |  9 ++++
 packages/vitest/src/node/state.ts             |  4 +-
 packages/vitest/src/node/types/config.ts      | 10 +++++
 packages/vitest/src/types/global.ts           |  1 +
 packages/ws-client/src/state.ts               |  4 +-
 test/config/test/blob-label.test.ts           | 41 +++++++++++++++++++
 7 files changed, 87 insertions(+), 4 deletions(-)
 create mode 100644 packages/vitest/src/node/pools/applyBlobLabel.ts
 create mode 100644 test/config/test/blob-label.test.ts

diff --git a/packages/vitest/src/node/pools/applyBlobLabel.ts b/packages/vitest/src/node/pools/applyBlobLabel.ts
new file mode 100644
index 000000000000..7b6873f1a595
--- /dev/null
+++ b/packages/vitest/src/node/pools/applyBlobLabel.ts
@@ -0,0 +1,22 @@
+import type { File } from '@vitest/runner'
+import { calculateSuiteHash, generateFileHash } from '@vitest/runner/utils'
+
+/**
+ * Rewrite file.id and all child task IDs so that the same test file run under
+ * different blob labels produces a distinct entry in state.filesMap.
+ *
+ * Mirrors the `__typecheck__` pattern in typecheck/collect.ts:
+ *   hash key = `${projectName}:__typecheck__`, file.meta.typecheck = true
+ *
+ * For blob labels:
+ *   hash key = `${projectName} [${label}]`, file.meta.blobLabel = label
+ */
+export function applyBlobLabel(files: File[], label: string, projectName: string | undefined): void {
+  for (const file of files) {
+    const hashName = projectName ? `${projectName} [${label}]` : `[${label}]`
+    file.id = generateFileHash(file.name, hashName)
+    file.meta = { ...file.meta, blobLabel: label }
+    // Recompute all child task IDs derived positionally from file.id
+    calculateSuiteHash(file)
+  }
+}
diff --git a/packages/vitest/src/node/pools/rpc.ts b/packages/vitest/src/node/pools/rpc.ts
index 1d09a45b87c5..149c0132f910 100644
--- a/packages/vitest/src/node/pools/rpc.ts
+++ b/packages/vitest/src/node/pools/rpc.ts
@@ -7,6 +7,7 @@ import { cleanUrl } from '@vitest/utils/helpers'
 import { isBuiltin, toBuiltin } from '../../utils/modules'
 import { handleRollupError } from '../environments/fetchModule'
 import { normalizeResolvedIdToUrl } from '../environments/normalizeUrl'
+import { applyBlobLabel } from './applyBlobLabel'
 
 interface MethodsOptions {
   cacheFs?: boolean
@@ -103,6 +104,10 @@ export function createMethodsRPC(project: TestProject, methodsOptions: MethodsOp
       return { code: result?.code }
     },
     async onQueued(file) {
+      const label = project.config.blobLabel
+      if (label) {
+        applyBlobLabel([file], label, project.name)
+      }
       if (methodsOptions.collect) {
         vitest.state.collectFiles(project, [file])
       }
@@ -111,6 +116,10 @@ export function createMethodsRPC(project: TestProject, methodsOptions: MethodsOp
       }
     },
     async onCollected(files) {
+      const label = project.config.blobLabel
+      if (label) {
+        applyBlobLabel(files, label, project.name)
+      }
       if (methodsOptions.collect) {
         vitest.state.collectFiles(project, files)
       }
diff --git a/packages/vitest/src/node/state.ts b/packages/vitest/src/node/state.ts
index 89159941c1ba..c34dffa1d6e8 100644
--- a/packages/vitest/src/node/state.ts
+++ b/packages/vitest/src/node/state.ts
@@ -146,10 +146,10 @@ export class StateManager {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
       const otherFiles = existing.filter(
-        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck,
+        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck || i.meta.blobLabel !== file.meta.blobLabel,
       )
       const currentFile = existing.find(
-        i => i.projectName === file.projectName,
+        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.blobLabel === file.meta.blobLabel,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index 3f6ec9ece2db..7d95d2501e2f 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -1107,6 +1107,15 @@ export interface UserConfig extends InlineConfig {
    * Log all available tags instead of running tests.
    */
   listTags?: boolean | 'json'
+
+  // TODO:
+  // move to blob reporter level option? but this influences the entire test run.
+  /**
+   * Label to disambiguate the same test file when run under different conditions
+   * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and
+   * `File.meta.blobLabel` so that state treats each label as a distinct entry.
+   */
+  blobLabel?: string
 }
 
 export type OnUnhandledErrorCallback = (error: (TestError | Error) & { type: string }) => boolean | void
@@ -1211,6 +1220,7 @@ export interface ResolvedConfig
   vmMemoryLimit?: UserConfig['vmMemoryLimit']
   dumpDir?: string
   tagsFilter?: string[]
+  blobLabel?: string
 
   experimental: Omit<Required<UserConfig>['experimental'], 'importDurations'> & {
     importDurations: {
diff --git a/packages/vitest/src/types/global.ts b/packages/vitest/src/types/global.ts
index 53297e36e85e..fe9c595440cf 100644
--- a/packages/vitest/src/types/global.ts
+++ b/packages/vitest/src/types/global.ts
@@ -110,6 +110,7 @@ declare module '@vitest/runner' {
   interface TaskMeta {
     typecheck?: boolean
     benchmark?: boolean
+    blobLabel?: string
   }
 
   interface File {
diff --git a/packages/ws-client/src/state.ts b/packages/ws-client/src/state.ts
index 4c93940c044c..eba136a043aa 100644
--- a/packages/ws-client/src/state.ts
+++ b/packages/ws-client/src/state.ts
@@ -48,10 +48,10 @@ export class StateManager {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
       const otherProject = existing.filter(
-        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck,
+        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck || i.meta.blobLabel !== file.meta.blobLabel,
       )
       const currentFile = existing.find(
-        i => i.projectName === file.projectName,
+        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.blobLabel === file.meta.blobLabel,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/test/config/test/blob-label.test.ts b/test/config/test/blob-label.test.ts
new file mode 100644
index 000000000000..da5270888e2c
--- /dev/null
+++ b/test/config/test/blob-label.test.ts
@@ -0,0 +1,41 @@
+import { expect, test } from 'vitest'
+import { generateFileHash } from '@vitest/runner/utils'
+import { runInlineTests } from '../../test-utils'
+
+const BASIC_TEST = `
+import { test } from 'vitest'
+test('t', () => {})
+`
+
+test('no blobLabel: file has no meta.blobLabel and normal id', async () => {
+  const { ctx } = await runInlineTests({
+    'a.test.ts': BASIC_TEST,
+  })
+  const files = ctx!.state.getFiles()
+  expect(files).toHaveLength(1)
+  expect(files[0].meta.blobLabel).toBeUndefined()
+  expect(files[0].id).toBe(generateFileHash('a.test.ts', undefined))
+})
+
+test('blobLabel: file.meta.blobLabel is set and id uses label-salted hash', async () => {
+  const { ctx } = await runInlineTests(
+    { 'a.test.ts': BASIC_TEST },
+    { blobLabel: 'linux' },
+  )
+  const files = ctx!.state.getFiles()
+  expect(files).toHaveLength(1)
+  expect(files[0].meta.blobLabel).toBe('linux')
+  expect(files[0].id).toBe(generateFileHash('a.test.ts', '[linux]'))
+})
+
+test('blobLabel: child task ids derived from new file.id', async () => {
+  const { ctx: noLabel } = await runInlineTests({ 'a.test.ts': BASIC_TEST })
+  const { ctx: withLabel } = await runInlineTests(
+    { 'a.test.ts': BASIC_TEST },
+    { blobLabel: 'linux' },
+  )
+  const taskNoLabel = noLabel!.state.getFiles()[0].tasks[0]
+  const taskWithLabel = withLabel!.state.getFiles()[0].tasks[0]
+  expect(taskWithLabel.id).not.toBe(taskNoLabel.id)
+  expect(taskWithLabel.id).toBe(`${withLabel!.state.getFiles()[0].id}_0`)
+})

From 54ebad41f5c126be92863dcb98f733c7645f715f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:10:21 +0900
Subject: [PATCH 02/65] wip: cleanup

---
 .../vitest/src/node/pools/applyBlobLabel.ts   | 22 -------------------
 packages/vitest/src/node/pools/rpc.ts         |  9 --------
 2 files changed, 31 deletions(-)
 delete mode 100644 packages/vitest/src/node/pools/applyBlobLabel.ts

diff --git a/packages/vitest/src/node/pools/applyBlobLabel.ts b/packages/vitest/src/node/pools/applyBlobLabel.ts
deleted file mode 100644
index 7b6873f1a595..000000000000
--- a/packages/vitest/src/node/pools/applyBlobLabel.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-import type { File } from '@vitest/runner'
-import { calculateSuiteHash, generateFileHash } from '@vitest/runner/utils'
-
-/**
- * Rewrite file.id and all child task IDs so that the same test file run under
- * different blob labels produces a distinct entry in state.filesMap.
- *
- * Mirrors the `__typecheck__` pattern in typecheck/collect.ts:
- *   hash key = `${projectName}:__typecheck__`, file.meta.typecheck = true
- *
- * For blob labels:
- *   hash key = `${projectName} [${label}]`, file.meta.blobLabel = label
- */
-export function applyBlobLabel(files: File[], label: string, projectName: string | undefined): void {
-  for (const file of files) {
-    const hashName = projectName ? `${projectName} [${label}]` : `[${label}]`
-    file.id = generateFileHash(file.name, hashName)
-    file.meta = { ...file.meta, blobLabel: label }
-    // Recompute all child task IDs derived positionally from file.id
-    calculateSuiteHash(file)
-  }
-}
diff --git a/packages/vitest/src/node/pools/rpc.ts b/packages/vitest/src/node/pools/rpc.ts
index 149c0132f910..1d09a45b87c5 100644
--- a/packages/vitest/src/node/pools/rpc.ts
+++ b/packages/vitest/src/node/pools/rpc.ts
@@ -7,7 +7,6 @@ import { cleanUrl } from '@vitest/utils/helpers'
 import { isBuiltin, toBuiltin } from '../../utils/modules'
 import { handleRollupError } from '../environments/fetchModule'
 import { normalizeResolvedIdToUrl } from '../environments/normalizeUrl'
-import { applyBlobLabel } from './applyBlobLabel'
 
 interface MethodsOptions {
   cacheFs?: boolean
@@ -104,10 +103,6 @@ export function createMethodsRPC(project: TestProject, methodsOptions: MethodsOp
       return { code: result?.code }
     },
     async onQueued(file) {
-      const label = project.config.blobLabel
-      if (label) {
-        applyBlobLabel([file], label, project.name)
-      }
       if (methodsOptions.collect) {
         vitest.state.collectFiles(project, [file])
       }
@@ -116,10 +111,6 @@ export function createMethodsRPC(project: TestProject, methodsOptions: MethodsOp
       }
     },
     async onCollected(files) {
-      const label = project.config.blobLabel
-      if (label) {
-        applyBlobLabel(files, label, project.name)
-      }
       if (methodsOptions.collect) {
         vitest.state.collectFiles(project, files)
       }

From f4ca239ee1039b2eda5986d4038304618acfb386 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:22:40 +0900
Subject: [PATCH 03/65] wip: idSeed on runner

---
 packages/runner/src/collect.ts                     | 2 +-
 packages/runner/src/types/runner.ts                | 1 +
 packages/runner/src/utils/collect.ts               | 6 ++++--
 packages/vitest/src/node/cli/cli-config.ts         | 4 ++++
 packages/vitest/src/node/config/serializeConfig.ts | 2 ++
 packages/vitest/src/node/types/config.ts           | 1 +
 packages/vitest/src/runtime/config.ts              | 1 +
 packages/vitest/src/runtime/runners/test.ts        | 4 ++++
 8 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/packages/runner/src/collect.ts b/packages/runner/src/collect.ts
index b422a3079400..7240cbaed0a8 100644
--- a/packages/runner/src/collect.ts
+++ b/packages/runner/src/collect.ts
@@ -47,7 +47,7 @@ export async function collectTests(
 
         const fileTags: string[] = typeof spec === 'string' ? [] : (spec.fileTags || [])
 
-        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment)
+        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, config.idSeed)
         file.tags = fileTags
         file.shuffle = config.sequence.shuffle
 
diff --git a/packages/runner/src/types/runner.ts b/packages/runner/src/types/runner.ts
index d05ab8056004..3298c736c515 100644
--- a/packages/runner/src/types/runner.ts
+++ b/packages/runner/src/types/runner.ts
@@ -45,6 +45,7 @@ export interface VitestRunnerConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
+  idSeed?: string
 }
 
 /**
diff --git a/packages/runner/src/utils/collect.ts b/packages/runner/src/utils/collect.ts
index 4c741ac2f478..624194657fde 100644
--- a/packages/runner/src/utils/collect.ts
+++ b/packages/runner/src/utils/collect.ts
@@ -199,10 +199,11 @@ export function createFileTask(
   projectName: string | undefined,
   pool?: string,
   viteEnvironment?: string,
+  idSeed?: string,
 ): File {
   const path = relative(root, filepath)
   const file: File = {
-    id: generateFileHash(path, projectName),
+    id: generateFileHash(path, projectName, idSeed),
     name: path,
     fullName: path,
     type: 'suite',
@@ -228,8 +229,9 @@ export function createFileTask(
 export function generateFileHash(
   file: string,
   projectName: string | undefined,
+  idSeed?: string,
 ): string {
-  return /* @__PURE__ */ generateHash(`${file}${projectName || ''}`)
+  return /* @__PURE__ */ generateHash(`${file}${projectName || ''}${idSeed ? `\0${idSeed}` : ''}`)
 }
 
 export function findTestFileStackTrace(testFilePath: string, error: string): ParsedStack | undefined {
diff --git a/packages/vitest/src/node/cli/cli-config.ts b/packages/vitest/src/node/cli/cli-config.ts
index 852372f76824..b5f8fc5c7a6f 100644
--- a/packages/vitest/src/node/cli/cli-config.ts
+++ b/packages/vitest/src/node/cli/cli-config.ts
@@ -830,6 +830,10 @@ export const cliOptionsConfig: VitestCLIOptions = {
     description: 'List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.',
     argument: '[type]',
   },
+  blobLabel: {
+    description: 'Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--blob-label=linux`).',
+    argument: '<label>',
+  },
   clearCache: {
     description: 'Delete all Vitest caches, including `experimental.fsModuleCache`, without running any tests. This will reduce the performance in the subsequent test run.',
   },
diff --git a/packages/vitest/src/node/config/serializeConfig.ts b/packages/vitest/src/node/config/serializeConfig.ts
index ca0115c32eb8..8f251b2eb89a 100644
--- a/packages/vitest/src/node/config/serializeConfig.ts
+++ b/packages/vitest/src/node/config/serializeConfig.ts
@@ -143,6 +143,8 @@ export function serializeConfig(project: TestProject): SerializedConfig {
     tags: config.tags || [],
     tagsFilter: config.tagsFilter,
     strictTags: config.strictTags ?? true,
+    // TODO
+    idSeed: config.blobLabel,
     slowTestThreshold:
       config.slowTestThreshold
       ?? globalConfig.slowTestThreshold
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index 7d95d2501e2f..42f2b264c29c 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -1149,6 +1149,7 @@ export interface ResolvedConfig
     | 'vmMemoryLimit'
     | 'fileParallelism'
     | 'tagsFilter'
+    | 'blobLabel'
   > {
   mode: VitestRunMode
 
diff --git a/packages/vitest/src/runtime/config.ts b/packages/vitest/src/runtime/config.ts
index f2e2cbbf8304..c8e0c332d3b1 100644
--- a/packages/vitest/src/runtime/config.ts
+++ b/packages/vitest/src/runtime/config.ts
@@ -145,6 +145,7 @@ export interface SerializedConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
+  idSeed: string | undefined
   slowTestThreshold: number | undefined
   isAgent: boolean
 }
diff --git a/packages/vitest/src/runtime/runners/test.ts b/packages/vitest/src/runtime/runners/test.ts
index e0986b83ddf1..c12814f1eabf 100644
--- a/packages/vitest/src/runtime/runners/test.ts
+++ b/packages/vitest/src/runtime/runners/test.ts
@@ -77,6 +77,10 @@ export class TestRunner implements VitestTestRunner {
 
   onCollectStart(file: File): void {
     this.workerState.current = file
+    // TODO: review
+    if (this.config.idSeed) {
+      file.meta.blobLabel = this.config.idSeed
+    }
   }
 
   onCleanupWorkerContext(listener: () => unknown): void {

From 2fd6d657abe2d7321da670c114ecf616d6f13814 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:24:08 +0900
Subject: [PATCH 04/65] chore: no slop

---
 test/config/test/blob-label.test.ts | 41 -----------------------------
 1 file changed, 41 deletions(-)
 delete mode 100644 test/config/test/blob-label.test.ts

diff --git a/test/config/test/blob-label.test.ts b/test/config/test/blob-label.test.ts
deleted file mode 100644
index da5270888e2c..000000000000
--- a/test/config/test/blob-label.test.ts
+++ /dev/null
@@ -1,41 +0,0 @@
-import { expect, test } from 'vitest'
-import { generateFileHash } from '@vitest/runner/utils'
-import { runInlineTests } from '../../test-utils'
-
-const BASIC_TEST = `
-import { test } from 'vitest'
-test('t', () => {})
-`
-
-test('no blobLabel: file has no meta.blobLabel and normal id', async () => {
-  const { ctx } = await runInlineTests({
-    'a.test.ts': BASIC_TEST,
-  })
-  const files = ctx!.state.getFiles()
-  expect(files).toHaveLength(1)
-  expect(files[0].meta.blobLabel).toBeUndefined()
-  expect(files[0].id).toBe(generateFileHash('a.test.ts', undefined))
-})
-
-test('blobLabel: file.meta.blobLabel is set and id uses label-salted hash', async () => {
-  const { ctx } = await runInlineTests(
-    { 'a.test.ts': BASIC_TEST },
-    { blobLabel: 'linux' },
-  )
-  const files = ctx!.state.getFiles()
-  expect(files).toHaveLength(1)
-  expect(files[0].meta.blobLabel).toBe('linux')
-  expect(files[0].id).toBe(generateFileHash('a.test.ts', '[linux]'))
-})
-
-test('blobLabel: child task ids derived from new file.id', async () => {
-  const { ctx: noLabel } = await runInlineTests({ 'a.test.ts': BASIC_TEST })
-  const { ctx: withLabel } = await runInlineTests(
-    { 'a.test.ts': BASIC_TEST },
-    { blobLabel: 'linux' },
-  )
-  const taskNoLabel = noLabel!.state.getFiles()[0].tasks[0]
-  const taskWithLabel = withLabel!.state.getFiles()[0].tasks[0]
-  expect(taskWithLabel.id).not.toBe(taskNoLabel.id)
-  expect(taskWithLabel.id).toBe(`${withLabel!.state.getFiles()[0].id}_0`)
-})

From 1a542426789587654ebe7b2a0d1c94481f37e8cc Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:27:22 +0900
Subject: [PATCH 05/65] chore: todo

---
 packages/ws-client/src/state.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/ws-client/src/state.ts b/packages/ws-client/src/state.ts
index eba136a043aa..36d00fbd904a 100644
--- a/packages/ws-client/src/state.ts
+++ b/packages/ws-client/src/state.ts
@@ -47,6 +47,7 @@ export class StateManager {
   collectFiles(files: File[] = []): void {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
+      // TODO
       const otherProject = existing.filter(
         i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck || i.meta.blobLabel !== file.meta.blobLabel,
       )

From 0401f210aa8a2c4c9f7d0e37558da9260bfe3394 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:40:20 +0900
Subject: [PATCH 06/65] refactor: move meta to createFileTask

---
 packages/runner/src/collect.ts                     |  2 +-
 packages/runner/src/types/runner.ts                |  2 +-
 packages/runner/src/utils/collect.ts               | 14 ++++++++------
 packages/vitest/src/node/config/serializeConfig.ts |  3 +--
 packages/vitest/src/node/test-specification.ts     |  9 ++-------
 packages/vitest/src/runtime/config.ts              |  2 +-
 packages/vitest/src/runtime/runners/test.ts        |  4 ----
 packages/vitest/src/typecheck/collect.ts           |  5 ++---
 8 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/packages/runner/src/collect.ts b/packages/runner/src/collect.ts
index 7240cbaed0a8..6bb5002c7207 100644
--- a/packages/runner/src/collect.ts
+++ b/packages/runner/src/collect.ts
@@ -47,7 +47,7 @@ export async function collectTests(
 
         const fileTags: string[] = typeof spec === 'string' ? [] : (spec.fileTags || [])
 
-        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, config.idSeed)
+        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, { blobLabel: config.blobLabel })
         file.tags = fileTags
         file.shuffle = config.sequence.shuffle
 
diff --git a/packages/runner/src/types/runner.ts b/packages/runner/src/types/runner.ts
index 3298c736c515..2a0180fceae2 100644
--- a/packages/runner/src/types/runner.ts
+++ b/packages/runner/src/types/runner.ts
@@ -45,7 +45,7 @@ export interface VitestRunnerConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  idSeed?: string
+  blobLabel?: string
 }
 
 /**
diff --git a/packages/runner/src/utils/collect.ts b/packages/runner/src/utils/collect.ts
index 624194657fde..9ad7a9086026 100644
--- a/packages/runner/src/utils/collect.ts
+++ b/packages/runner/src/utils/collect.ts
@@ -1,5 +1,5 @@
 import type { ParsedStack } from '@vitest/utils'
-import type { File, Suite, TaskBase } from '../types/tasks'
+import type { File, Suite, TaskBase, TaskMeta } from '../types/tasks'
 import { processError } from '@vitest/utils/error'
 import { parseSingleStack } from '@vitest/utils/source-map'
 import { relative } from 'pathe'
@@ -199,18 +199,18 @@ export function createFileTask(
   projectName: string | undefined,
   pool?: string,
   viteEnvironment?: string,
-  idSeed?: string,
+  meta?: { typecheck?: boolean, blobLabel?: string },
 ): File {
   const path = relative(root, filepath)
   const file: File = {
-    id: generateFileHash(path, projectName, idSeed),
+    id: generateFileHash(path, projectName, meta),
     name: path,
     fullName: path,
     type: 'suite',
     mode: 'queued',
     filepath,
     tasks: [],
-    meta: Object.create(null),
+    meta: Object.assign(Object.create(null), meta) as TaskMeta,
     projectName,
     file: undefined!,
     pool,
@@ -229,9 +229,11 @@ export function createFileTask(
 export function generateFileHash(
   file: string,
   projectName: string | undefined,
-  idSeed?: string,
+  meta?: { typecheck?: boolean, blobLabel?: string },
 ): string {
-  return /* @__PURE__ */ generateHash(`${file}${projectName || ''}${idSeed ? `\0${idSeed}` : ''}`)
+  return /* @__PURE__ */ generateHash(
+    `${file}${projectName || ''}${meta?.typecheck ? ':__typecheck__' : ''}${meta?.blobLabel ? `\0${meta.blobLabel}` : ''}`,
+  )
 }
 
 export function findTestFileStackTrace(testFilePath: string, error: string): ParsedStack | undefined {
diff --git a/packages/vitest/src/node/config/serializeConfig.ts b/packages/vitest/src/node/config/serializeConfig.ts
index 8f251b2eb89a..69625aa68b70 100644
--- a/packages/vitest/src/node/config/serializeConfig.ts
+++ b/packages/vitest/src/node/config/serializeConfig.ts
@@ -143,8 +143,7 @@ export function serializeConfig(project: TestProject): SerializedConfig {
     tags: config.tags || [],
     tagsFilter: config.tagsFilter,
     strictTags: config.strictTags ?? true,
-    // TODO
-    idSeed: config.blobLabel,
+    blobLabel: config.blobLabel,
     slowTestThreshold:
       config.slowTestThreshold
       ?? globalConfig.slowTestThreshold
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index 6ac1c9f7cadb..a712db07ffe7 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -57,15 +57,10 @@ export class TestSpecification {
     testLinesOrOptions?: number[] | TestSpecificationOptions | undefined,
   ) {
     const projectName = project.config.name
-    const hashName = pool !== 'typescript'
-      ? projectName
-      : projectName
-      // https://github.com/vitest-dev/vitest/blob/main/packages/vitest/src/typecheck/collect.ts#L58
-        ? `${projectName}:__typecheck__`
-        : '__typecheck__'
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
-      hashName,
+      projectName,
+      { typecheck: pool === 'typescript' },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/packages/vitest/src/runtime/config.ts b/packages/vitest/src/runtime/config.ts
index c8e0c332d3b1..b37417eb2f59 100644
--- a/packages/vitest/src/runtime/config.ts
+++ b/packages/vitest/src/runtime/config.ts
@@ -145,7 +145,7 @@ export interface SerializedConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  idSeed: string | undefined
+  blobLabel: string | undefined
   slowTestThreshold: number | undefined
   isAgent: boolean
 }
diff --git a/packages/vitest/src/runtime/runners/test.ts b/packages/vitest/src/runtime/runners/test.ts
index c12814f1eabf..e0986b83ddf1 100644
--- a/packages/vitest/src/runtime/runners/test.ts
+++ b/packages/vitest/src/runtime/runners/test.ts
@@ -77,10 +77,6 @@ export class TestRunner implements VitestTestRunner {
 
   onCollectStart(file: File): void {
     this.workerState.current = file
-    // TODO: review
-    if (this.config.idSeed) {
-      file.meta.blobLabel = this.config.idSeed
-    }
   }
 
   onCleanupWorkerContext(listener: () => unknown): void {
diff --git a/packages/vitest/src/typecheck/collect.ts b/packages/vitest/src/typecheck/collect.ts
index c6c5e571d90d..d228f4bb1736 100644
--- a/packages/vitest/src/typecheck/collect.ts
+++ b/packages/vitest/src/typecheck/collect.ts
@@ -4,7 +4,7 @@ import type { TestProject } from '../node/project'
 import {
   calculateSuiteHash,
   createTaskName,
-  generateHash,
+  generateFileHash,
   interpretTaskModes,
   someTasksAreOnly,
 } from '@vitest/runner/utils'
@@ -55,11 +55,10 @@ export async function collectTests(
   const ast = await parseAstAsync(request.code)
   const testFilepath = relative(ctx.config.root, filepath)
   const projectName = ctx.name
-  const typecheckSubprojectName = projectName ? `${projectName}:__typecheck__` : '__typecheck__'
   const file: ParsedFile = {
     filepath,
     type: 'suite',
-    id: generateHash(`${testFilepath}${typecheckSubprojectName}`),
+    id: generateFileHash(testFilepath, projectName, { typecheck: true }),
     name: testFilepath,
     fullName: testFilepath,
     mode: 'run',

From ed59ffc94036b3814c559f515091a332f9ae5f9a Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 12:43:33 +0900
Subject: [PATCH 07/65] refactor: nit

---
 packages/runner/src/utils/collect.ts | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/packages/runner/src/utils/collect.ts b/packages/runner/src/utils/collect.ts
index 9ad7a9086026..19b5b28ca7d1 100644
--- a/packages/runner/src/utils/collect.ts
+++ b/packages/runner/src/utils/collect.ts
@@ -1,5 +1,5 @@
 import type { ParsedStack } from '@vitest/utils'
-import type { File, Suite, TaskBase, TaskMeta } from '../types/tasks'
+import type { File, Suite, TaskBase } from '../types/tasks'
 import { processError } from '@vitest/utils/error'
 import { parseSingleStack } from '@vitest/utils/source-map'
 import { relative } from 'pathe'
@@ -199,7 +199,7 @@ export function createFileTask(
   projectName: string | undefined,
   pool?: string,
   viteEnvironment?: string,
-  meta?: { typecheck?: boolean, blobLabel?: string },
+  meta?: { typecheck?: boolean; blobLabel?: string },
 ): File {
   const path = relative(root, filepath)
   const file: File = {
@@ -210,7 +210,7 @@ export function createFileTask(
     mode: 'queued',
     filepath,
     tasks: [],
-    meta: Object.assign(Object.create(null), meta) as TaskMeta,
+    meta: Object.assign(Object.create(null), meta),
     projectName,
     file: undefined!,
     pool,
@@ -229,11 +229,15 @@ export function createFileTask(
 export function generateFileHash(
   file: string,
   projectName: string | undefined,
-  meta?: { typecheck?: boolean, blobLabel?: string },
+  meta?: { typecheck?: boolean; blobLabel?: string },
 ): string {
-  return /* @__PURE__ */ generateHash(
-    `${file}${projectName || ''}${meta?.typecheck ? ':__typecheck__' : ''}${meta?.blobLabel ? `\0${meta.blobLabel}` : ''}`,
-  )
+  const seed = [
+    file,
+    projectName || '',
+    meta?.typecheck ? '__typecheck__' : '',
+    meta?.blobLabel || '',
+  ].join('\0')
+  return generateHash(seed)
 }
 
 export function findTestFileStackTrace(testFilePath: string, error: string): ParsedStack | undefined {

From 71cb47b921a538cf43c8af0c55a2c6049b88efb0 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:07:29 +0900
Subject: [PATCH 08/65] refactor: nit

---
 packages/vitest/src/node/state.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/vitest/src/node/state.ts b/packages/vitest/src/node/state.ts
index c34dffa1d6e8..853b93065f1d 100644
--- a/packages/vitest/src/node/state.ts
+++ b/packages/vitest/src/node/state.ts
@@ -145,17 +145,17 @@ export class StateManager {
   collectFiles(project: TestProject, files: File[] = []): void {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
-      const otherFiles = existing.filter(
-        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck || i.meta.blobLabel !== file.meta.blobLabel,
-      )
       const currentFile = existing.find(
-        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.blobLabel === file.meta.blobLabel,
+        i => i.projectName === file.projectName
+          && i.meta.typecheck === file.meta.typecheck
+          && i.meta.blobLabel === file.meta.blobLabel,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
       if (currentFile) {
         file.logs = currentFile.logs
       }
+      const otherFiles = existing.filter(i => i !== currentFile)
       otherFiles.push(file)
       this.filesMap.set(file.filepath, otherFiles)
       this.updateId(file, project)

From ebc5fddda46592b5753d05eb9cff24b2b9617186 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:11:05 +0900
Subject: [PATCH 09/65] chore: todo

---
 packages/vitest/src/node/types/config.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index 42f2b264c29c..b6fef4473929 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -1110,6 +1110,7 @@ export interface UserConfig extends InlineConfig {
 
   // TODO:
   // move to blob reporter level option? but this influences the entire test run.
+  // or just label: string?
   /**
    * Label to disambiguate the same test file when run under different conditions
    * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and

From 408b84ba7a3d50d2e2076e57c9f137363e6dd3bb Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:12:00 +0900
Subject: [PATCH 10/65] refactor: nit

---
 packages/ws-client/src/state.ts | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/packages/ws-client/src/state.ts b/packages/ws-client/src/state.ts
index 36d00fbd904a..e1e9f8ca3492 100644
--- a/packages/ws-client/src/state.ts
+++ b/packages/ws-client/src/state.ts
@@ -47,10 +47,6 @@ export class StateManager {
   collectFiles(files: File[] = []): void {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
-      // TODO
-      const otherProject = existing.filter(
-        i => i.projectName !== file.projectName || i.meta.typecheck !== file.meta.typecheck || i.meta.blobLabel !== file.meta.blobLabel,
-      )
       const currentFile = existing.find(
         i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.blobLabel === file.meta.blobLabel,
       )
@@ -59,8 +55,9 @@ export class StateManager {
       if (currentFile) {
         file.logs = currentFile.logs
       }
-      otherProject.push(file)
-      this.filesMap.set(file.filepath, otherProject)
+      const otherFiles = existing.filter(i => i !== currentFile)
+      otherFiles.push(file)
+      this.filesMap.set(file.filepath, otherFiles)
       this.updateId(file)
     })
   }

From 4505799c1d3e7c49a7ce2383535d0fe3cdbea8f4 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:13:00 +0900
Subject: [PATCH 11/65] chore: still thinking

---
 packages/vitest/src/types/global.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/vitest/src/types/global.ts b/packages/vitest/src/types/global.ts
index fe9c595440cf..918d59fa7d06 100644
--- a/packages/vitest/src/types/global.ts
+++ b/packages/vitest/src/types/global.ts
@@ -110,6 +110,7 @@ declare module '@vitest/runner' {
   interface TaskMeta {
     typecheck?: boolean
     benchmark?: boolean
+    // TODO: rename it `label`? also accomodate `label: "__typecheck__"`?
     blobLabel?: string
   }
 

From ea56508e601de95831ffef04b9c616f406f0b94f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:17:12 +0900
Subject: [PATCH 12/65] chore: lint

---
 docs/guide/cli-generated.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/guide/cli-generated.md b/docs/guide/cli-generated.md
index ddf59427ce05..cdc565068c84 100644
--- a/docs/guide/cli-generated.md
+++ b/docs/guide/cli-generated.md
@@ -875,6 +875,13 @@ Start Vitest without running tests. Tests will be running only on change. If bro
 
 List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.
 
+### blobLabel
+
+- **CLI:** `--blobLabel <label>`
+- **Config:** [blobLabel](/config/bloblabel)
+
+Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--blob-label=linux`).
+
 ### clearCache
 
 - **CLI:** `--clearCache`

From 183ede543ee7c7df9d939b86ca4ab4cf3f6c6cbe Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 13:50:31 +0900
Subject: [PATCH 13/65] chore: todo

---
 packages/vitest/src/typecheck/collect.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/vitest/src/typecheck/collect.ts b/packages/vitest/src/typecheck/collect.ts
index d228f4bb1736..67912e72ac52 100644
--- a/packages/vitest/src/typecheck/collect.ts
+++ b/packages/vitest/src/typecheck/collect.ts
@@ -55,6 +55,7 @@ export async function collectTests(
   const ast = await parseAstAsync(request.code)
   const testFilepath = relative(ctx.config.root, filepath)
   const projectName = ctx.name
+  // TODO: use createFileTask directly?
   const file: ParsedFile = {
     filepath,
     type: 'suite',

From 31d2e960535c1e109b5cf28afb1cc4ecc951a3bf Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:00:20 +0900
Subject: [PATCH 14/65] test: e2e

---
 test/cli/test/reporters/merge-reports.test.ts | 79 ++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 2f445b5c20f9..f0b1ef6e6ba7 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -2,7 +2,7 @@ import type { File, Test } from '@vitest/runner/types'
 import type { TestUserConfig, Vitest } from 'vitest/node'
 import { rmSync } from 'node:fs'
 import { resolve } from 'node:path'
-import { runVitest } from '#test-utils'
+import { runVitest, useFS } from '#test-utils'
 import { playwright } from '@vitest/browser-playwright'
 import { createFileTask } from '@vitest/runner/utils'
 import { beforeEach, expect, test } from 'vitest'
@@ -481,3 +481,80 @@ function createTest(name: string, file: File): Test {
     context: {} as any,
   }
 }
+
+// TODO:
+// - with projects
+// - with browser mode
+// - with browser mode multiple instances
+test('merge reports of different results with labels', async () => {
+  const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
+  useFS(root, {
+    'first.test.ts': `
+test("always good", () => {})
+
+test("works on linux", () => {
+  expect(process.env.TEST_LABEL_ENV === 'linux').toBe(true)
+})
+
+test("works on macos", () => {
+  expect(process.env.TEST_LABEL_ENV === 'macos').toBe(true)
+})
+`,
+    'second.test.ts': `
+test("linux only", () => {})
+`,
+    'third.test.ts': `
+test("macos only", () => {})
+`,
+  })
+  process.env.TEST_LABEL_ENV = 'linux'
+  const result1 = await runVitest({
+    root,
+    globals: true,
+    blobLabel: 'linux',
+    reporters: 'blob',
+  }, ['first', 'second'])
+  expect(result1.stderr).toMatchInlineSnapshot(`""`)
+  expect(result1.errorTree()).toMatchInlineSnapshot(`
+    {
+      "first.test.ts": {
+        "always good": "passed",
+        "works on linux": "passed",
+        "works on macos": [
+          "expected false to be true // Object.is equality",
+        ],
+      },
+      "second.test.ts": {
+        "linux only": "passed",
+      },
+    }
+  `)
+  process.env.TEST_LABEL_ENV = 'macos'
+  const result2 = await runVitest({
+    root,
+    globals: true,
+    blobLabel: 'macos',
+    reporters: 'blob',
+  }, ['first', 'third'])
+  expect(result2.stderr).toMatchInlineSnapshot(`""`)
+  expect(result2.errorTree()).toMatchInlineSnapshot(`
+    {
+      "first.test.ts": {
+        "always good": "passed",
+        "works on linux": [
+          "expected false to be true // Object.is equality",
+        ],
+        "works on macos": "passed",
+      },
+      "third.test.ts": {
+        "macos only": "passed",
+      },
+    }
+  `)
+  // TODO: different labels
+  const result = await runVitest({
+    root,
+    mergeReports: resolve(root, '.vitest-reports'),
+  })
+  expect(result.errorTree()).toMatchInlineSnapshot(`{}`)
+})

From ec104cc2512d56ba3ea989705d9eee1292f1d89b Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:05:32 +0900
Subject: [PATCH 15/65] wip: blob label as suffix

---
 packages/vitest/src/node/reporters/blob.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index 32dd65948bd7..f2c793806fe1 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -50,9 +50,9 @@ export class BlobReporter implements Reporter {
       = this.options.outputFile ?? getOutputFile(this.ctx.config, 'blob')
     if (!outputFile) {
       const shard = this.ctx.config.shard
-      outputFile = shard
-        ? `.vitest-reports/blob-${shard.index}-${shard.count}.json`
-        : '.vitest-reports/blob.json'
+      const label = this.ctx.config.blobLabel ?? process.env.VITEST_BLOB_LABEL
+      const suffix = [label, shard && `${shard.index}-${shard.count}`].filter(Boolean).join('-')
+      outputFile = suffix ? `.vitest-reports/blob-${suffix}.json` : '.vitest-reports/blob.json'
     }
 
     const environmentModules: MergeReportEnvironmentModules = {}

From 57260d640898bfbd58cd666f13fce317e735cb6b Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:10:10 +0900
Subject: [PATCH 16/65] fix: TestSpecification taskId with blobLabel

---
 .../vitest/src/node/test-specification.ts     |  2 +-
 test/cli/test/reporters/merge-reports.test.ts | 20 +++++++++++++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index a712db07ffe7..7a8b33bcb176 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -60,7 +60,7 @@ export class TestSpecification {
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      { typecheck: pool === 'typescript' },
+      { typecheck: pool === 'typescript', blobLabel: project.config.blobLabel },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index f0b1ef6e6ba7..8d3d441fa01c 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -551,10 +551,26 @@ test("macos only", () => {})
       },
     }
   `)
-  // TODO: different labels
+  // TODO: support meta split for `errorTree` helper
   const result = await runVitest({
     root,
     mergeReports: resolve(root, '.vitest-reports'),
   })
-  expect(result.errorTree()).toMatchInlineSnapshot(`{}`)
+  expect(result.errorTree()).toMatchInlineSnapshot(`
+    {
+      "first.test.ts": {
+        "always good": "passed",
+        "works on linux": [
+          "expected false to be true // Object.is equality",
+        ],
+        "works on macos": "passed",
+      },
+      "second.test.ts": {
+        "linux only": "passed",
+      },
+      "third.test.ts": {
+        "macos only": "passed",
+      },
+    }
+  `)
 })

From b04a95a20903b591e65734674847038057bcff42 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:21:29 +0900
Subject: [PATCH 17/65] test: support errorTree({ fileLabel: true })

---
 test/cli/test/reporters/merge-reports.test.ts | 16 +++++++++++-----
 test/test-utils/index.ts                      | 19 +++++++++++++------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 8d3d441fa01c..c481bd156451 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -551,24 +551,30 @@ test("macos only", () => {})
       },
     }
   `)
-  // TODO: support meta split for `errorTree` helper
   const result = await runVitest({
     root,
     mergeReports: resolve(root, '.vitest-reports'),
   })
-  expect(result.errorTree()).toMatchInlineSnapshot(`
+  expect(result.errorTree({ fileLabel: true })).toMatchInlineSnapshot(`
     {
-      "first.test.ts": {
+      "first.test.ts (linux)": {
+        "always good": "passed",
+        "works on linux": "passed",
+        "works on macos": [
+          "expected false to be true // Object.is equality",
+        ],
+      },
+      "first.test.ts (macos)": {
         "always good": "passed",
         "works on linux": [
           "expected false to be true // Object.is equality",
         ],
         "works on macos": "passed",
       },
-      "second.test.ts": {
+      "second.test.ts (linux)": {
         "linux only": "passed",
       },
-      "third.test.ts": {
+      "third.test.ts (macos)": {
         "macos only": "passed",
       },
     }
diff --git a/test/test-utils/index.ts b/test/test-utils/index.ts
index de9ad68d35df..65ef410c49f5 100644
--- a/test/test-utils/index.ts
+++ b/test/test-utils/index.ts
@@ -1,6 +1,6 @@
 import type { Options } from 'tinyexec'
 import type { UserConfig as ViteUserConfig } from 'vite'
-import type { SerializedConfig, TestContext, WorkerGlobalState } from 'vitest'
+import type { ParsedStack, SerializedConfig, TestContext, WorkerGlobalState } from 'vitest'
 import type { TestProjectConfiguration } from 'vitest/config'
 import type {
   TestCase,
@@ -242,7 +242,7 @@ export async function runVitest(
     get results() {
       return ctx?.state.getTestModules() || []
     },
-    errorTree(options?: { project?: boolean; stackTrace?: boolean }) {
+    errorTree(options?: BuildErrorTreeOptions & { project?: boolean }) {
       const modules = ctx?.state.getTestModules() || []
       const tree = options?.project
         ? buildErrorProjectTree(modules, options)
@@ -571,10 +571,15 @@ export class StableTestFileOrderSorter {
   }
 }
 
-export function buildErrorTree(testModules: TestModule[], options?: { stackTrace?: boolean }) {
+interface BuildErrorTreeOptions {
+  stackTrace?: boolean
+  fileLabel?: boolean
+}
+
+export function buildErrorTree(testModules: TestModule[], options?: BuildErrorTreeOptions) {
   const root = testModules[0]?.project.config.root
 
-  function mapError(e: { message: string; stacks?: { file: string; line: number; column: number; method: string }[] }) {
+  function mapError(e: { message: string; stacks?: ParsedStack[] }) {
     if (options?.stackTrace) {
       const stacks = (e.stacks || []).map((s) => {
         const loc = `${relative(root, s.file)}:${s.line}:${s.column}`
@@ -614,6 +619,7 @@ export function buildErrorTree(testModules: TestModule[], options?: { stackTrace
       }
       return moduleChildren
     },
+    options?.fileLabel ? module => `${module.relativeModuleId} (${module.meta().blobLabel})` : undefined,
   )
 }
 
@@ -622,6 +628,7 @@ export function buildTestTree(
   onTestCase?: (result: TestCase) => unknown,
   onTestSuite?: (testSuite: TestSuite, suiteChildren: Record<string, any>) => unknown,
   onTestModule?: (testModule: TestModule, moduleChildren: Record<string, any>) => unknown,
+  onTestModuleKey?: (testModule: TestModule) => string,
 ) {
   type TestTree = Record<string, any>
 
@@ -652,7 +659,7 @@ export function buildTestTree(
 
   for (const module of testModules) {
     // Use relative module ID for cleaner output
-    const key = module.relativeModuleId
+    const key = onTestModuleKey ? onTestModuleKey(module) : module.relativeModuleId
     const moduleChildren = walkCollection(module.children)
     tree[key] = onTestModule ? onTestModule(module, moduleChildren) : moduleChildren
   }
@@ -674,7 +681,7 @@ export function buildTestProjectTree(testModules: TestModule[], onTestCase?: (re
   return projectTree
 }
 
-export function buildErrorProjectTree(testModules: TestModule[], options?: { stackTrace?: boolean }) {
+export function buildErrorProjectTree(testModules: TestModule[], options?: BuildErrorTreeOptions) {
   const projectTree: Record<string, Record<string, any>> = {}
 
   for (const testModule of testModules) {

From 41ab8295fd8e277910b2ecb0c96eb80da41feb93 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:26:13 +0900
Subject: [PATCH 18/65] chore: todo

---
 test/cli/test/reporters/merge-reports.test.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index c481bd156451..9af16782332a 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -555,6 +555,15 @@ test("macos only", () => {})
     root,
     mergeReports: resolve(root, '.vitest-reports'),
   })
+  // TODO: what...
+  expect(result.stderr).toMatchInlineSnapshot(`
+    "No test files found, exiting with code 1
+
+    include: **/*.{test,spec}.?(c|m)[jt]s?(x)
+    exclude:  **/node_modules/**, **/.git/**
+
+    "
+  `)
   expect(result.errorTree({ fileLabel: true })).toMatchInlineSnapshot(`
     {
       "first.test.ts (linux)": {

From 799bb54641a3b46a94314fa8fa3e30c73c03eb64 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:34:51 +0900
Subject: [PATCH 19/65] fix: fix meta task id on merge-reports

---
 packages/vitest/src/node/core.ts              |  2 +-
 packages/vitest/src/node/project.ts           |  4 ++
 .../vitest/src/node/test-specification.ts     |  4 +-
 test/cli/test/reporters/merge-reports.test.ts | 43 +++++++++++++++++--
 4 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/packages/vitest/src/node/core.ts b/packages/vitest/src/node/core.ts
index 60ce250c24bb..d99e1c93df98 100644
--- a/packages/vitest/src/node/core.ts
+++ b/packages/vitest/src/node/core.ts
@@ -613,7 +613,7 @@ export class Vitest {
       const specifications: TestSpecification[] = []
       for (const file of files) {
         const project = this.getProjectByName(file.projectName || '')
-        const specification = project.createSpecification(file.filepath, undefined, file.pool)
+        const specification = project.createSpecification(file.filepath, undefined, file.pool, file.meta)
         specifications.push(specification)
       }
 
diff --git a/packages/vitest/src/node/project.ts b/packages/vitest/src/node/project.ts
index b6f687db692e..f18ea92e7638 100644
--- a/packages/vitest/src/node/project.ts
+++ b/packages/vitest/src/node/project.ts
@@ -1,3 +1,4 @@
+import type { TaskMeta } from '@vitest/runner/types'
 import type { GlobOptions } from 'tinyglobby'
 import type { DevEnvironment, ViteDevServer, InlineConfig as ViteInlineConfig } from 'vite'
 import type { ModuleRunner } from 'vite/module-runner'
@@ -152,12 +153,15 @@ export class TestProject {
     locationsOrOptions?: number[] | TestSpecificationOptions | undefined,
     /** @internal */
     pool?: string,
+    /** @internal */
+    meta?: TaskMeta,
   ): TestSpecification {
     return new TestSpecification(
       this,
       moduleId,
       pool || getFilePoolName(this),
       locationsOrOptions,
+      meta,
     )
   }
 
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index 7a8b33bcb176..af0094acf338 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -1,3 +1,4 @@
+import type { TaskMeta } from '@vitest/runner/types'
 import type { SerializedTestSpecification } from '../runtime/types/utils'
 import type { TestProject } from './project'
 import type { TestModule } from './reporters/reported-tasks'
@@ -55,12 +56,13 @@ export class TestSpecification {
     moduleId: string,
     pool: Pool,
     testLinesOrOptions?: number[] | TestSpecificationOptions | undefined,
+    meta?: TaskMeta,
   ) {
     const projectName = project.config.name
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      { typecheck: pool === 'typescript', blobLabel: project.config.blobLabel },
+      meta ?? { typecheck: pool === 'typescript', blobLabel: project.config.blobLabel },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 9af16782332a..57ee3f8f158c 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -555,12 +555,47 @@ test("macos only", () => {})
     root,
     mergeReports: resolve(root, '.vitest-reports'),
   })
-  // TODO: what...
   expect(result.stderr).toMatchInlineSnapshot(`
-    "No test files found, exiting with code 1
+    "
+    ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 2 ⎯⎯⎯⎯⎯⎯⎯
+
+     FAIL  first.test.ts > works on macos
+    AssertionError: expected false to be true // Object.is equality
+
+    - Expected
+    + Received
+
+    - true
+    + false
+
+     ❯ first.test.ts:9:50
+          7|
+          8| test("works on macos", () => {
+          9|   expect(process.env.TEST_LABEL_ENV === 'macos').toBe(true)
+           |                                                  ^
+         10| })
+         11|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/2]⎯
+
+     FAIL  first.test.ts > works on linux
+    AssertionError: expected false to be true // Object.is equality
+
+    - Expected
+    + Received
+
+    - true
+    + false
+
+     ❯ first.test.ts:5:50
+          3|
+          4| test("works on linux", () => {
+          5|   expect(process.env.TEST_LABEL_ENV === 'linux').toBe(true)
+           |                                                  ^
+          6| })
+          7|
 
-    include: **/*.{test,spec}.?(c|m)[jt]s?(x)
-    exclude:  **/node_modules/**, **/.git/**
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[2/2]⎯
 
     "
   `)

From e99860027230db33039d59460e920c01617790b3 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:43:20 +0900
Subject: [PATCH 20/65] test: update with new hash

---
 test/cli/test/reported-tasks.test.ts      | 24 ++++++++++++++---------
 test/cli/test/test-specifications.test.ts | 18 ++++++++++++++---
 2 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/test/cli/test/reported-tasks.test.ts b/test/cli/test/reported-tasks.test.ts
index d5248674c291..4769fe082b27 100644
--- a/test/cli/test/reported-tasks.test.ts
+++ b/test/cli/test/reported-tasks.test.ts
@@ -320,20 +320,26 @@ it('can create new test specifications', ({ testModule }) => {
   const testSuite = [...testModule.children.suites()][0]
   const suiteSpec = testSuite.toTestSpecification()
   expect(suiteSpec.moduleId).toBe(testModule.moduleId)
-  expect(suiteSpec.testIds).toEqual([
-    '-1008553841_11_0',
-    '-1008553841_11_1',
-    '-1008553841_11_2_0',
-    '-1008553841_11_2_1',
-    '-1008553841_11_2_2',
-    '-1008553841_11_2_3',
-  ])
+  expect(suiteSpec.testIds).toMatchInlineSnapshot(`
+    [
+      "1763725585_11_0",
+      "1763725585_11_1",
+      "1763725585_11_2_0",
+      "1763725585_11_2_1",
+      "1763725585_11_2_2",
+      "1763725585_11_2_3",
+    ]
+  `)
   expect(suiteSpec.project).toBe(testModule.project)
 
   const testCase = testSuite.children.at(0) as TestCase
   const caseSpec = testCase.toTestSpecification()
   expect(caseSpec.moduleId).toBe(testModule.moduleId)
-  expect(caseSpec.testIds).toEqual(['-1008553841_11_0'])
+  expect(caseSpec.testIds).toMatchInlineSnapshot(`
+    [
+      "1763725585_11_0",
+    ]
+  `)
   expect(caseSpec.project).toBe(testModule.project)
 })
 
diff --git a/test/cli/test/test-specifications.test.ts b/test/cli/test/test-specifications.test.ts
index f0f745ecccfd..0d5f05ee6e25 100644
--- a/test/cli/test/test-specifications.test.ts
+++ b/test/cli/test/test-specifications.test.ts
@@ -2,13 +2,13 @@ import type { TestSpecificationOptions } from 'vitest/node'
 import { expect, test } from 'vitest'
 import { runInlineTests } from '../../test-utils'
 
-test.each(
+test.for(
   [
     { testNamePattern: /two/ },
     { testLines: [8] },
-    { testIds: ['-109630875_1'] },
+    { testIds: ['-1838252165_1'] },
   ] satisfies TestSpecificationOptions[],
-)('runs with options %o', async (options) => {
+)('runs with options %o', async (options, { onTestFailed }) => {
   const { fs, ctx, errorTree } = await runInlineTests({
     'basic.test.js': /* js */ `
       import { test, expect } from 'vitest'
@@ -33,6 +33,18 @@ test.each(
   )
 
   await vitest.runTestSpecifications([specification])
+  onTestFailed(() => {
+    console.log('⚠️⚠️⚠️ Failed options', options)
+    for (const [id, task] of vitest.state.idMap.entries()) {
+      console.log({
+        id,
+        name: task.name,
+        mode: task.mode,
+        type: task.type,
+        location: task.location,
+      })
+    }
+  })
 
   expect(errorTree()).toEqual({
     'basic.test.js': {

From be8611c74f0f6d7ac1f12f3e4c45fdfade0e994d Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:49:03 +0900
Subject: [PATCH 21/65] wip: label in reporter

---
 packages/vitest/src/node/reporters/base.ts    | 4 ++++
 packages/vitest/src/node/reporters/summary.ts | 5 +++++
 test/cli/test/reporters/merge-reports.test.ts | 1 +
 3 files changed, 10 insertions(+)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index edd1fd63b5e2..d2e5a96ce045 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,6 +335,10 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
+    if (entity.meta().blobLabel) {
+      title += ` ${c.bgCyan(c.bold(` ${entity.meta().blobLabel} `))}`
+    }
+
     return title
   }
 
diff --git a/packages/vitest/src/node/reporters/summary.ts b/packages/vitest/src/node/reporters/summary.ts
index 26a236cd16ec..9b22e6eb0d28 100644
--- a/packages/vitest/src/node/reporters/summary.ts
+++ b/packages/vitest/src/node/reporters/summary.ts
@@ -38,7 +38,9 @@ interface RunningModule extends Pick<Counter, 'total' | 'completed'> {
   projectColor: TestModule['project']['color']
   hook?: Omit<SlowTask, 'hook'>
   tests: Map<TestCase['id'], SlowTask>
+  // TODO: keep it in one meta?
   typecheck: boolean
+  blobLabel?: string
 }
 
 /**
@@ -289,10 +291,12 @@ export class SummaryReporter implements Reporter {
 
     for (const testFile of Array.from(this.runningModules.values()).sort(sortRunningModules)) {
       const typecheck = testFile.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
+      const blobLabel = testFile.blobLabel ? `${c.bgCyan(c.bold(` ${testFile.blobLabel} `))} ` : ''
       summary.push(
         c.bold(c.yellow(` ${F_POINTER} `))
         + formatProjectName({ name: testFile.projectName, color: testFile.projectColor })
         + typecheck
+        + blobLabel
         + testFile.filename
         + c.dim(!testFile.completed && !testFile.total
           ? ' [queued]'
@@ -399,5 +403,6 @@ function initializeStats(module: TestModule): RunningModule {
     projectColor: module.project.color,
     tests: new Map(),
     typecheck: !!module.task.meta.typecheck,
+    blobLabel: module.task.meta.blobLabel,
   }
 }
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 57ee3f8f158c..5a4220e4db6b 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -486,6 +486,7 @@ function createTest(name: string, file: File): Test {
 // - with projects
 // - with browser mode
 // - with browser mode multiple instances
+// - reporter output
 test('merge reports of different results with labels', async () => {
   const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
   useFS(root, {

From c99178d25004ef991ac0f5c040ab5eb05a2edfff Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:50:18 +0900
Subject: [PATCH 22/65] wip: label in error summary

---
 packages/vitest/src/node/reporters/base.ts    | 3 ++-
 test/cli/test/reporters/merge-reports.test.ts | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index d2e5a96ce045..925a8c17b44f 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -933,6 +933,7 @@ export abstract class BaseReporter implements Reporter {
         const filepath = (task as File)?.filepath || ''
         const projectName = (task as File)?.projectName || task.file?.projectName || ''
         const project = this.ctx.projects.find(p => p.name === projectName)
+        const blobLabel = (task as File)?.meta?.blobLabel || task.file?.meta?.blobLabel
 
         let name = this.getFullName(task, separator)
 
@@ -941,7 +942,7 @@ export abstract class BaseReporter implements Reporter {
         }
 
         this.ctx.logger.error(
-          `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${name}`,
+          `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${blobLabel ? `${c.bgCyan(c.bold(` ${blobLabel} `))} ` : ''}${name}`,
         )
       }
 
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 5a4220e4db6b..f6a9dd03629b 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -560,7 +560,7 @@ test("macos only", () => {})
     "
     ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 2 ⎯⎯⎯⎯⎯⎯⎯
 
-     FAIL  first.test.ts > works on macos
+     FAIL   linux  first.test.ts > works on macos
     AssertionError: expected false to be true // Object.is equality
 
     - Expected
@@ -579,7 +579,7 @@ test("macos only", () => {})
 
     ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/2]⎯
 
-     FAIL  first.test.ts > works on linux
+     FAIL   macos  first.test.ts > works on linux
     AssertionError: expected false to be true // Object.is equality
 
     - Expected

From 29394706ca8914e7098faaa48d99ec4573c38797 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:52:16 +0900
Subject: [PATCH 23/65] test: update hash id

---
 test/cli/test/reporters/__snapshots__/html.test.ts.snap | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/cli/test/reporters/__snapshots__/html.test.ts.snap b/test/cli/test/reporters/__snapshots__/html.test.ts.snap
index 723134a6c4e5..7970f6317854 100644
--- a/test/cli/test/reporters/__snapshots__/html.test.ts.snap
+++ b/test/cli/test/reporters/__snapshots__/html.test.ts.snap
@@ -185,7 +185,7 @@ exports[`html reporter > resolves to "passing" status for test file "all-passing
           "file": [Circular],
           "fullName": "all-passing-or-skipped.test.ts > 3 + 3 = 6",
           "fullTestName": "3 + 3 = 6",
-          "id": "1111755131_1",
+          "id": "1804288165_1",
           "location": {
             "column": 6,
             "line": 7,

From 4ae0de81fad4950124e870cc788388652d62f225 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 14:54:50 +0900
Subject: [PATCH 24/65] chore: todo

---
 packages/vitest/src/node/reporters/base.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index 925a8c17b44f..116d2b360e25 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,6 +335,7 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
+    // TODO: tweak styles
     if (entity.meta().blobLabel) {
       title += ` ${c.bgCyan(c.bold(` ${entity.meta().blobLabel} `))}`
     }

From 028fde700535607450a3d4517c9121dbbe76de3e Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:16:31 +0900
Subject: [PATCH 25/65] fix: more label in reporter

---
 packages/vitest/src/node/reporters/base.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index 116d2b360e25..508a8b61e4ae 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,9 +335,9 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
-    // TODO: tweak styles
-    if (entity.meta().blobLabel) {
-      title += ` ${c.bgCyan(c.bold(` ${entity.meta().blobLabel} `))}`
+    const blobLabel = entity.task.file.meta.blobLabel
+    if (blobLabel) {
+      title += ` ${c.bgCyan(c.bold(` ${blobLabel} `))}`
     }
 
     return title
@@ -934,7 +934,6 @@ export abstract class BaseReporter implements Reporter {
         const filepath = (task as File)?.filepath || ''
         const projectName = (task as File)?.projectName || task.file?.projectName || ''
         const project = this.ctx.projects.find(p => p.name === projectName)
-        const blobLabel = (task as File)?.meta?.blobLabel || task.file?.meta?.blobLabel
 
         let name = this.getFullName(task, separator)
 
@@ -942,6 +941,7 @@ export abstract class BaseReporter implements Reporter {
           name += c.dim(` [ ${this.relative(filepath)} ]`)
         }
 
+        const blobLabel = task.file?.meta?.blobLabel
         this.ctx.logger.error(
           `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${blobLabel ? `${c.bgCyan(c.bold(` ${blobLabel} `))} ` : ''}${name}`,
         )

From 4980969c540e17c029e55d58618d71f4dfb5d708 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:17:20 +0900
Subject: [PATCH 26/65] test: update

---
 test/cli/test/reporters/merge-reports.test.ts | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index f6a9dd03629b..9ac8a515a3b6 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -556,6 +556,23 @@ test("macos only", () => {})
     root,
     mergeReports: resolve(root, '.vitest-reports'),
   })
+  expect(trimReporterOutput(result.stdout)).toMatchInlineSnapshot(`
+    "✓  linux  first.test.ts > always good <time>
+     ✓  linux  first.test.ts > works on linux <time>
+     ×  linux  first.test.ts > works on macos <time>
+       → expected false to be true // Object.is equality
+     ✓  linux  second.test.ts > linux only <time>
+     ✓  macos  first.test.ts > always good <time>
+     ×  macos  first.test.ts > works on linux <time>
+       → expected false to be true // Object.is equality
+     ✓  macos  first.test.ts > works on macos <time>
+     ✓  macos  third.test.ts > macos only <time>
+
+     Test Files  2 failed | 2 passed (4)
+          Tests  2 failed | 6 passed (8)
+       Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)
+       Per blob  <time> <time>"
+  `)
   expect(result.stderr).toMatchInlineSnapshot(`
     "
     ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 2 ⎯⎯⎯⎯⎯⎯⎯

From 7502f5e4b1695b236d9d35c4ddbcf46ebea4b00b Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:21:30 +0900
Subject: [PATCH 27/65] test: fix typecheck

---
 test/test-utils/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test-utils/index.ts b/test/test-utils/index.ts
index 65ef410c49f5..4f7ba358a470 100644
--- a/test/test-utils/index.ts
+++ b/test/test-utils/index.ts
@@ -571,7 +571,7 @@ export class StableTestFileOrderSorter {
   }
 }
 
-interface BuildErrorTreeOptions {
+export interface BuildErrorTreeOptions {
   stackTrace?: boolean
   fileLabel?: boolean
 }

From 570c7b14abba46b088c76b75faecefc05e805513 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:26:24 +0900
Subject: [PATCH 28/65] chore: fix ts exact property nonsense

---
 packages/runner/src/types/runner.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runner/src/types/runner.ts b/packages/runner/src/types/runner.ts
index 2a0180fceae2..d45645b008e4 100644
--- a/packages/runner/src/types/runner.ts
+++ b/packages/runner/src/types/runner.ts
@@ -45,7 +45,7 @@ export interface VitestRunnerConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  blobLabel?: string
+  blobLabel: string | undefined
 }
 
 /**

From b8f50f1e257ebddf731ec62eb2c9a77eed75e5c4 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:27:24 +0900
Subject: [PATCH 29/65] test: update

---
 test/cli/test/reporters/merge-reports.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 9ac8a515a3b6..4374079b12de 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -486,7 +486,7 @@ function createTest(name: string, file: File): Test {
 // - with projects
 // - with browser mode
 // - with browser mode multiple instances
-// - reporter output
+// - with typecheck
 test('merge reports of different results with labels', async () => {
   const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
   useFS(root, {

From 65c8f4c175cc31c8bce657737a45bb986404c596 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:28:15 +0900
Subject: [PATCH 30/65] feat: display blobLabel in UI reporter

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 packages/ui/client/components/FileDetails.vue           | 3 +++
 packages/ui/client/components/explorer/Explorer.vue     | 1 +
 packages/ui/client/components/explorer/ExplorerItem.vue | 3 +++
 packages/ui/client/components/views/ViewTestReport.vue  | 1 +
 packages/ui/client/composables/explorer/types.ts        | 1 +
 packages/ui/client/composables/explorer/utils.ts        | 2 ++
 6 files changed, 11 insertions(+)

diff --git a/packages/ui/client/components/FileDetails.vue b/packages/ui/client/components/FileDetails.vue
index 0c9e65a06f8e..4a85ef12344d 100644
--- a/packages/ui/client/components/FileDetails.vue
+++ b/packages/ui/client/components/FileDetails.vue
@@ -60,6 +60,8 @@ const isTypecheck = computed(() => {
   return !!current.value?.meta?.typecheck
 })
 
+const blobLabel = computed(() => current.value?.meta?.blobLabel)
+
 function open() {
   const filePath = current.value?.filepath
   if (filePath) {
@@ -206,6 +208,7 @@ const tags = computed(() => {
       <div p="2" h-10 flex="~ gap-2" items-center bg-header border="b base">
         <StatusIcon :state="current.result?.state" :mode="current.mode" :failed-snapshot="failedSnapshot" />
         <div v-if="isTypecheck" v-tooltip.bottom="'This is a typecheck test. It won\'t report results of the runtime tests'" class="i-logos:typescript-icon" flex-shrink-0 />
+        <span v-if="blobLabel" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ blobLabel }}</span>
         <span
           v-if="current?.file.projectName"
           class="rounded-full py-0.5 px-2 text-xs font-light"
diff --git a/packages/ui/client/components/explorer/Explorer.vue b/packages/ui/client/components/explorer/Explorer.vue
index 5a9227a15590..4bdd13ab7bae 100644
--- a/packages/ui/client/components/explorer/Explorer.vue
+++ b/packages/ui/client/components/explorer/Explorer.vue
@@ -331,6 +331,7 @@ const {
                 :indent="item.indent"
                 :name="item.name"
                 :typecheck="item.typecheck === true"
+                :blob-label="item.blobLabel"
                 :project-name="item.projectName ?? ''"
                 :project-name-color="item.projectNameColor ?? ''"
                 :state="item.state"
diff --git a/packages/ui/client/components/explorer/ExplorerItem.vue b/packages/ui/client/components/explorer/ExplorerItem.vue
index 4e7f93302f3f..007702d3a3a7 100644
--- a/packages/ui/client/components/explorer/ExplorerItem.vue
+++ b/packages/ui/client/components/explorer/ExplorerItem.vue
@@ -25,6 +25,7 @@ const {
   opened,
   expandable,
   typecheck,
+  blobLabel,
   type,
   disableTaskLocation,
   onItemClick,
@@ -35,6 +36,7 @@ const {
   name: string
   indent: number
   typecheck?: boolean
+  blobLabel?: string
   duration?: number
   slow?: boolean
   state?: TaskState
@@ -216,6 +218,7 @@ const tagsBgGradient = computed(() => {
     <StatusIcon :state="state" :mode="task.mode" :failed-snapshot="failedSnapshot" w-4 />
     <div flex items-baseline gap-2 overflow-hidden>
       <div v-if="type === 'file' && typecheck" v-tooltip.bottom="'This is a typecheck test. It won\'t report results of the runtime tests'" class="i-logos:typescript-icon" flex-shrink-0 />
+      <span v-if="type === 'file' && blobLabel" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ blobLabel }}</span>
       <span text-sm truncate font-light>
         <span v-if="type === 'file' && projectName" class="rounded-full py-0.5 px-2 mr-1 text-xs" :style="{ backgroundColor: projectNameColor, color: projectNameTextColor }">
           {{ projectName }}
diff --git a/packages/ui/client/components/views/ViewTestReport.vue b/packages/ui/client/components/views/ViewTestReport.vue
index 19e841bf6408..9c55351132b1 100644
--- a/packages/ui/client/components/views/ViewTestReport.vue
+++ b/packages/ui/client/components/views/ViewTestReport.vue
@@ -25,6 +25,7 @@ const failed = computed(() => {
 const kWellKnownMeta = new Set([
   'benchmark',
   'typecheck',
+  'blobLabel',
 ])
 const meta = computed(() => {
   return Object.entries(props.test.meta).filter(([name]) => {
diff --git a/packages/ui/client/composables/explorer/types.ts b/packages/ui/client/composables/explorer/types.ts
index a51056f3853e..585806b9afc2 100644
--- a/packages/ui/client/composables/explorer/types.ts
+++ b/packages/ui/client/composables/explorer/types.ts
@@ -63,6 +63,7 @@ export interface FileTreeNode extends ParentTreeNode {
   type: 'file'
   filepath: string
   typecheck: boolean | undefined
+  blobLabel?: string
   projectName?: string
   projectNameColor: string
   collectDuration?: number
diff --git a/packages/ui/client/composables/explorer/utils.ts b/packages/ui/client/composables/explorer/utils.ts
index 294ecb5a0026..82ced02fa47d 100644
--- a/packages/ui/client/composables/explorer/utils.ts
+++ b/packages/ui/client/composables/explorer/utils.ts
@@ -84,6 +84,7 @@ export function createOrUpdateFileNode(
 
   if (fileNode) {
     fileNode.typecheck = !!file.meta && 'typecheck' in file.meta
+    fileNode.blobLabel = file.meta?.blobLabel
     fileNode.state = file.result?.state
     fileNode.mode = file.mode
     fileNode.duration = typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined
@@ -106,6 +107,7 @@ export function createOrUpdateFileNode(
       children: new Set(),
       tasks: [],
       typecheck: !!file.meta && 'typecheck' in file.meta,
+      blobLabel: file.meta?.blobLabel,
       indent: 0,
       duration: typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined,
       slow: false,

From 79e78db3ad924a6a60d48e1fb0365d84658bb176 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:31:56 +0900
Subject: [PATCH 31/65] fix: remove VITEST_BLOB_LABEL

---
 packages/vitest/src/node/reporters/blob.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index f2c793806fe1..b4f3df28a6ce 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -50,7 +50,7 @@ export class BlobReporter implements Reporter {
       = this.options.outputFile ?? getOutputFile(this.ctx.config, 'blob')
     if (!outputFile) {
       const shard = this.ctx.config.shard
-      const label = this.ctx.config.blobLabel ?? process.env.VITEST_BLOB_LABEL
+      const label = this.ctx.config.blobLabel
       const suffix = [label, shard && `${shard.index}-${shard.count}`].filter(Boolean).join('-')
       outputFile = suffix ? `.vitest-reports/blob-${suffix}.json` : '.vitest-reports/blob.json'
     }

From 701a6d069be5236ae12e743bd113d4a595b84cce Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:44:22 +0900
Subject: [PATCH 32/65] fix: inline config

---
 packages/vitest/src/node/reporters/base.ts |  1 +
 packages/vitest/src/node/types/config.ts   | 20 ++++++++++----------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index 508a8b61e4ae..d2782ee1fcfc 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,6 +335,7 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
+    // TODO: show only during --merge-reports?
     const blobLabel = entity.task.file.meta.blobLabel
     if (blobLabel) {
       title += ` ${c.bgCyan(c.bold(` ${blobLabel} `))}`
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index b6fef4473929..50fbefac5607 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -961,6 +961,16 @@ export interface InlineConfig {
    * @default true
    */
   strictTags?: boolean
+
+  // TODO:
+  // move to blob reporter level option? but this influences the entire test run.
+  // or just label: string?
+  /**
+   * Label to disambiguate the same test file when run under different conditions
+   * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and
+   * `File.meta.blobLabel` so that state treats each label as a distinct entry.
+   */
+  blobLabel?: string
 }
 
 export interface TypecheckConfig {
@@ -1107,16 +1117,6 @@ export interface UserConfig extends InlineConfig {
    * Log all available tags instead of running tests.
    */
   listTags?: boolean | 'json'
-
-  // TODO:
-  // move to blob reporter level option? but this influences the entire test run.
-  // or just label: string?
-  /**
-   * Label to disambiguate the same test file when run under different conditions
-   * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and
-   * `File.meta.blobLabel` so that state treats each label as a distinct entry.
-   */
-  blobLabel?: string
 }
 
 export type OnUnhandledErrorCallback = (error: (TestError | Error) & { type: string }) => boolean | void

From 9e44f3ee44ae045ee5765fd6e155d236e396f57b Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 15:44:53 +0900
Subject: [PATCH 33/65] test: dogfood

---
 .github/workflows/ci.yml  | 54 +++++++++++++++++++++++++++++++++++++++
 test/cli/vitest.config.ts |  1 +
 test/core/vite.config.ts  |  1 +
 3 files changed, 56 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6ef6d0538d0b..35c388473a50 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -116,6 +116,8 @@ jobs:
 
       - name: Test
         run: pnpm run test:ci
+        env:
+          VITEST_CI_BLOB_LABEL: ${{ matrix.os }}-node-${{ matrix.node_version }}
 
       - name: Test Examples
         run: pnpm run test:examples
@@ -127,6 +129,17 @@ jobs:
           path: test/ui/test-results/
           retention-days: 30
 
+      - uses: actions/upload-artifact@v7
+        if: ${{ !cancelled() }}
+        with:
+          name: vitest-blob-${{ matrix.os }}-node-${{ matrix.node_version }}
+          path: |
+            README.md
+            test/core/.vitest-reports
+            test/cli/.vitest-reports
+          retention-days: 1
+          include-hidden-files: true
+
   test-cached:
     needs: changed
     name: 'Cache&Test: node-${{ matrix.node_version }}, ${{ matrix.os }}'
@@ -248,3 +261,44 @@ jobs:
           name: playwright-report-rolldown
           path: rolldown/test/ui/test-results/
           retention-days: 30
+
+  merge-reports:
+    needs: test
+    if: ${{ !cancelled() }}
+    runs-on: ubuntu-latest
+    name: Merge Reports
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: ./.github/actions/setup-and-cache
+
+      - name: Install
+        run: pnpm i
+
+      - name: Build
+        run: pnpm run build
+
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: vitest-blob-*
+          merge-multiple: true
+
+      - name: Merge reports
+        continue-on-error: true
+        run: |
+          pnpm --filter=./test/core --filter=./test/cli --no-bail --sequential test --merge-reports --reporter=html
+          mkdir -p html-merged
+          cp -rf test/core/html html-merged/core
+          cp -rf test/cli/html html-merged/cli
+
+      - uses: actions/upload-artifact@v7
+        id: upload-report
+        with:
+          name: vitest-merge-reports
+          path: html-merged
+          retention-days: 7
+
+      - name: Viewer link in summary
+        run: |
+          echo "[View HTML report](https://viewer.vitest.dev/?url=${{ steps.upload-report.outputs.artifact-url }})" >> $GITHUB_STEP_SUMMARY
diff --git a/test/cli/vitest.config.ts b/test/cli/vitest.config.ts
index 52442d43a4b2..2638758a48f7 100644
--- a/test/cli/vitest.config.ts
+++ b/test/cli/vitest.config.ts
@@ -25,6 +25,7 @@ export default defineConfig({
         return false
       }
     },
+    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
   },
   server: {
     watch: {
diff --git a/test/core/vite.config.ts b/test/core/vite.config.ts
index ab7e3aad425a..9094350188d1 100644
--- a/test/core/vite.config.ts
+++ b/test/core/vite.config.ts
@@ -195,6 +195,7 @@ export default defineConfig({
       project('forks', 'green'),
       project('vmThreads', 'blue'),
     ],
+    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
   },
 })
 

From e9dcb096a0546bead5e9500b8288b606b54ed1bf Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 16:18:38 +0900
Subject: [PATCH 34/65] test: fix merge report dogfooding

---
 .github/workflows/ci.yml  | 12 +++++++-----
 test/cli/vitest.config.ts |  9 +++++++--
 test/core/vite.config.ts  | 13 +++++++++----
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 35c388473a50..3c8246507d76 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -286,17 +286,19 @@ jobs:
 
       - name: Merge reports
         continue-on-error: true
+        run: pnpm --filter=./test/core --filter=./test/cli --no-bail --sequential test --merge-reports --reporter=html
+
+      - name: Merge reports html
         run: |
-          pnpm --filter=./test/core --filter=./test/cli --no-bail --sequential test --merge-reports --reporter=html
-          mkdir -p html-merged
-          cp -rf test/core/html html-merged/core
-          cp -rf test/cli/html html-merged/cli
+          mkdir -p html-all
+          cp -rf test/core/html html-all/core
+          cp -rf test/cli/html html-all/cli
 
       - uses: actions/upload-artifact@v7
         id: upload-report
         with:
           name: vitest-merge-reports
-          path: html-merged
+          path: html-all
           retention-days: 7
 
       - name: Viewer link in summary
diff --git a/test/cli/vitest.config.ts b/test/cli/vitest.config.ts
index 2638758a48f7..756799522835 100644
--- a/test/cli/vitest.config.ts
+++ b/test/cli/vitest.config.ts
@@ -4,7 +4,13 @@ export default defineConfig({
   test: {
     include: ['test/**/**.{test,spec}.ts'],
     includeTaskLocation: true,
-    reporters: ['verbose'],
+    reporters: [
+      'verbose',
+      ...(process.env.VITEST_CI_BLOB_LABEL
+        ? [['blob', {}] as any]
+        : []),
+    ],
+    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
     testTimeout: 60_000,
     isolate: false,
     fileParallelism: false,
@@ -25,7 +31,6 @@ export default defineConfig({
         return false
       }
     },
-    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
   },
   server: {
     watch: {
diff --git a/test/core/vite.config.ts b/test/core/vite.config.ts
index 9094350188d1..85d5d12c8a75 100644
--- a/test/core/vite.config.ts
+++ b/test/core/vite.config.ts
@@ -125,9 +125,15 @@ export default defineConfig({
       },
     },
     includeTaskLocation: true,
-    reporters: process.env.GITHUB_ACTIONS
-      ? ['default', ['github-actions', { displayAnnotations: false }]]
-      : [['default', { summary: true }], 'hanging-process'],
+    reporters: [
+      ...(process.env.GITHUB_ACTIONS
+        ? [['default'], ['github-actions', { displayAnnotations: false }] as any]
+        : [['default', { summary: true }], ['hanging-process']]),
+      ...(process.env.VITEST_CI_BLOB_LABEL
+        ? [['blob']]
+        : []),
+    ],
+    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
     testNamePattern: '^((?!does not include test that).)*$',
     coverage: {
       provider: 'istanbul',
@@ -195,7 +201,6 @@ export default defineConfig({
       project('forks', 'green'),
       project('vmThreads', 'blue'),
     ],
-    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
   },
 })
 

From af9d5482764390556a48e70ab7039e3867f6688e Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 16:57:15 +0900
Subject: [PATCH 35/65] ci: add short commit hash to merged report artifact
 name

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .github/workflows/ci.yml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3c8246507d76..ea24c1a1098e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -289,15 +289,17 @@ jobs:
         run: pnpm --filter=./test/core --filter=./test/cli --no-bail --sequential test --merge-reports --reporter=html
 
       - name: Merge reports html
+        id: merge-html
         run: |
           mkdir -p html-all
           cp -rf test/core/html html-all/core
           cp -rf test/cli/html html-all/cli
+          echo "short_sha=${GITHUB_SHA:0:7}" >> $GITHUB_OUTPUT
 
       - uses: actions/upload-artifact@v7
         id: upload-report
         with:
-          name: vitest-merge-reports
+          name: vitest-ci-report-${{ steps.merge-html.outputs.short_sha }}
           path: html-all
           retention-days: 7
 

From 173871c107b3ada92c79b69eb94cd055eb96a0f5 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 17:21:45 +0900
Subject: [PATCH 36/65] test: test projects and labels

---
 test/cli/test/reporters/merge-reports.test.ts | 223 +++++++++++++++++-
 1 file changed, 217 insertions(+), 6 deletions(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 4374079b12de..1f15068af3d5 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -1,3 +1,4 @@
+import type { RunVitestConfig } from '#test-utils'
 import type { File, Test } from '@vitest/runner/types'
 import type { TestUserConfig, Vitest } from 'vitest/node'
 import { rmSync } from 'node:fs'
@@ -482,12 +483,7 @@ function createTest(name: string, file: File): Test {
   }
 }
 
-// TODO:
-// - with projects
-// - with browser mode
-// - with browser mode multiple instances
-// - with typecheck
-test('merge reports of different results with labels', async () => {
+test('merge reports with labels', async () => {
   const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
   useFS(root, {
     'first.test.ts': `
@@ -642,3 +638,218 @@ test("macos only", () => {})
     }
   `)
 })
+
+test('merge reports with projects and labels', async () => {
+  const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
+  useFS(root, {
+    'first.test.ts': `
+import { test, expect } from "vitest";
+
+test("always good", () => {})
+
+test("works on node", () => {
+  expect(typeof window).toBe('undefined')
+})
+
+test("works on browser", () => {
+  expect(typeof window).not.toBe('undefined')
+})
+`,
+    'second.test.ts': `
+import { test, expect } from "vitest";
+
+test("also good", () => {})
+`,
+  })
+  const baseConfig: RunVitestConfig = {
+    root,
+    projects: [
+      {
+        extends: true,
+        test: {
+          name: 'node',
+        },
+      },
+      {
+        extends: true,
+        test: {
+          name: 'browser',
+          browser: {
+            enabled: true,
+            headless: true,
+            screenshotFailures: false,
+            provider: playwright(),
+            instances: [
+              {
+                browser: 'chromium',
+              },
+            ],
+          },
+        },
+      },
+    ],
+  }
+  const result1 = await runVitest({
+    ...baseConfig,
+    blobLabel: 'linux',
+    reporters: 'blob',
+  })
+  expect(result1.stderr).toMatchInlineSnapshot(`""`)
+  expect(result1.errorTree({ project: true })).toMatchInlineSnapshot(`
+    {
+      "browser (chromium)": {
+        "first.test.ts": {
+          "always good": "passed",
+          "works on browser": "passed",
+          "works on node": [
+            "expected 'object' to be 'undefined' // Object.is equality",
+          ],
+        },
+        "second.test.ts": {
+          "also good": "passed",
+        },
+      },
+      "node": {
+        "first.test.ts": {
+          "always good": "passed",
+          "works on browser": [
+            "expected 'undefined' not to be 'undefined' // Object.is equality",
+          ],
+          "works on node": "passed",
+        },
+        "second.test.ts": {
+          "also good": "passed",
+        },
+      },
+    }
+  `)
+  const result2 = await runVitest({
+    ...baseConfig,
+    blobLabel: 'macos',
+    reporters: 'blob',
+  })
+  expect(result2.stderr).toMatchInlineSnapshot(`""`)
+  expect(result2.errorTree({ project: true })).toMatchInlineSnapshot(`
+    {
+      "browser (chromium)": {
+        "first.test.ts": {
+          "always good": "passed",
+          "works on browser": "passed",
+          "works on node": [
+            "expected 'object' to be 'undefined' // Object.is equality",
+          ],
+        },
+        "second.test.ts": {
+          "also good": "passed",
+        },
+      },
+      "node": {
+        "first.test.ts": {
+          "always good": "passed",
+          "works on browser": [
+            "expected 'undefined' not to be 'undefined' // Object.is equality",
+          ],
+          "works on node": "passed",
+        },
+        "second.test.ts": {
+          "also good": "passed",
+        },
+      },
+    }
+  `)
+  const result = await runVitest({
+    ...baseConfig,
+    mergeReports: resolve(root, '.vitest-reports'),
+  })
+  expect(trimReporterOutput(result.stdout)).toMatchInlineSnapshot(`
+    "✓ |node| first.test.ts > always good <time>
+     ✓ |node| first.test.ts > works on node <time>
+     × |node| first.test.ts > works on browser <time>
+       → expected 'undefined' not to be 'undefined' // Object.is equality
+     ✓ |node| second.test.ts > also good <time>
+     ✓ |browser (chromium)| first.test.ts > always good <time>
+     × |browser (chromium)| first.test.ts > works on node <time>
+       → expected 'object' to be 'undefined' // Object.is equality
+     ✓ |browser (chromium)| first.test.ts > works on browser <time>
+     ✓ |browser (chromium)| second.test.ts > also good <time>
+     ✓ |node| first.test.ts > always good <time>
+     ✓ |node| first.test.ts > works on node <time>
+     × |node| first.test.ts > works on browser <time>
+       → expected 'undefined' not to be 'undefined' // Object.is equality
+     ✓ |node| second.test.ts > also good <time>
+     ✓ |browser (chromium)| second.test.ts > also good <time>
+     ✓ |browser (chromium)| first.test.ts > always good <time>
+     × |browser (chromium)| first.test.ts > works on node <time>
+       → expected 'object' to be 'undefined' // Object.is equality
+     ✓ |browser (chromium)| first.test.ts > works on browser <time>
+
+     Test Files  4 failed | 4 passed (8)
+          Tests  4 failed | 12 passed (16)
+       Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)
+       Per blob  <time> <time>"
+  `)
+  expect(result.stderr).toMatchInlineSnapshot(`
+    "
+    ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 4 ⎯⎯⎯⎯⎯⎯⎯
+
+     FAIL  |node| first.test.ts > works on browser
+     FAIL  |node| first.test.ts > works on browser
+    AssertionError: expected 'undefined' not to be 'undefined' // Object.is equality
+     ❯ first.test.ts:11:29
+          9|
+         10| test("works on browser", () => {
+         11|   expect(typeof window).not.toBe('undefined')
+           |                             ^
+         12| })
+         13|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/4]⎯
+
+     FAIL  |browser (chromium)| first.test.ts > works on node
+     FAIL  |browser (chromium)| first.test.ts > works on node
+    AssertionError: expected 'object' to be 'undefined' // Object.is equality
+
+    Expected: "undefined"
+    Received: "object"
+
+     ❯ first.test.ts:7:24
+          5|
+          6| test("works on node", () => {
+          7|   expect(typeof window).toBe('undefined')
+           |                        ^
+          8| })
+          9|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[2/4]⎯
+
+    "
+  `)
+  expect(result.errorTree({ project: true, fileLabel: true })).toMatchInlineSnapshot(`
+    {
+      "browser (chromium)": {
+        "first.test.ts (undefined)": {
+          "always good": "passed",
+          "works on browser": "passed",
+          "works on node": [
+            "expected 'object' to be 'undefined' // Object.is equality",
+          ],
+        },
+        "second.test.ts (undefined)": {
+          "also good": "passed",
+        },
+      },
+      "node": {
+        "first.test.ts (undefined)": {
+          "always good": "passed",
+          "works on browser": [
+            "expected 'undefined' not to be 'undefined' // Object.is equality",
+          ],
+          "works on node": "passed",
+        },
+        "second.test.ts (undefined)": {
+          "also good": "passed",
+        },
+      },
+    }
+  `)
+})

From 0cf50cfda89a59dcf55d0bb0c2631f60ffae87ec Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 17:42:32 +0900
Subject: [PATCH 37/65] fix: fix projects and labels

---
 packages/vitest/src/node/project.ts           |   1 +
 test/cli/test/reporters/merge-reports.test.ts | 114 ++++++++++--------
 2 files changed, 62 insertions(+), 53 deletions(-)

diff --git a/packages/vitest/src/node/project.ts b/packages/vitest/src/node/project.ts
index f18ea92e7638..db867f815b5e 100644
--- a/packages/vitest/src/node/project.ts
+++ b/packages/vitest/src/node/project.ts
@@ -555,6 +555,7 @@ export class TestProject {
       server.config,
     )
     this._config.api.token = this.vitest.config.api.token
+    this._config.blobLabel = this.vitest.config.blobLabel
     this._setHash()
     for (const _providedKey in this.config.provide) {
       const providedKey = _providedKey as keyof ProvidedContext
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 1f15068af3d5..6ac90820fecf 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -642,7 +642,7 @@ test("macos only", () => {})
 test('merge reports with projects and labels', async () => {
   const root = resolve(process.cwd(), `vitest-test-${crypto.randomUUID()}`)
   useFS(root, {
-    'first.test.ts': `
+    'basic.test.ts': `
 import { test, expect } from "vitest";
 
 test("always good", () => {})
@@ -654,12 +654,7 @@ test("works on node", () => {
 test("works on browser", () => {
   expect(typeof window).not.toBe('undefined')
 })
-`,
-    'second.test.ts': `
-import { test, expect } from "vitest";
-
-test("also good", () => {})
-`,
+`
   })
   const baseConfig: RunVitestConfig = {
     root,
@@ -668,12 +663,18 @@ test("also good", () => {})
         extends: true,
         test: {
           name: 'node',
+          sequence: {
+            groupOrder: 0,
+          },
         },
       },
       {
         extends: true,
         test: {
           name: 'browser',
+          sequence: {
+            groupOrder: 1,
+          },
           browser: {
             enabled: true,
             headless: true,
@@ -698,28 +699,22 @@ test("also good", () => {})
   expect(result1.errorTree({ project: true })).toMatchInlineSnapshot(`
     {
       "browser (chromium)": {
-        "first.test.ts": {
+        "basic.test.ts": {
           "always good": "passed",
           "works on browser": "passed",
           "works on node": [
             "expected 'object' to be 'undefined' // Object.is equality",
           ],
         },
-        "second.test.ts": {
-          "also good": "passed",
-        },
       },
       "node": {
-        "first.test.ts": {
+        "basic.test.ts": {
           "always good": "passed",
           "works on browser": [
             "expected 'undefined' not to be 'undefined' // Object.is equality",
           ],
           "works on node": "passed",
         },
-        "second.test.ts": {
-          "also good": "passed",
-        },
       },
     }
   `)
@@ -732,28 +727,22 @@ test("also good", () => {})
   expect(result2.errorTree({ project: true })).toMatchInlineSnapshot(`
     {
       "browser (chromium)": {
-        "first.test.ts": {
+        "basic.test.ts": {
           "always good": "passed",
           "works on browser": "passed",
           "works on node": [
             "expected 'object' to be 'undefined' // Object.is equality",
           ],
         },
-        "second.test.ts": {
-          "also good": "passed",
-        },
       },
       "node": {
-        "first.test.ts": {
+        "basic.test.ts": {
           "always good": "passed",
           "works on browser": [
             "expected 'undefined' not to be 'undefined' // Object.is equality",
           ],
           "works on node": "passed",
         },
-        "second.test.ts": {
-          "also good": "passed",
-        },
       },
     }
   `)
@@ -762,29 +751,25 @@ test("also good", () => {})
     mergeReports: resolve(root, '.vitest-reports'),
   })
   expect(trimReporterOutput(result.stdout)).toMatchInlineSnapshot(`
-    "✓ |node| first.test.ts > always good <time>
-     ✓ |node| first.test.ts > works on node <time>
-     × |node| first.test.ts > works on browser <time>
+    "✓ |node|  linux  basic.test.ts > always good <time>
+     ✓ |node|  linux  basic.test.ts > works on node <time>
+     × |node|  linux  basic.test.ts > works on browser <time>
        → expected 'undefined' not to be 'undefined' // Object.is equality
-     ✓ |node| second.test.ts > also good <time>
-     ✓ |browser (chromium)| first.test.ts > always good <time>
-     × |browser (chromium)| first.test.ts > works on node <time>
+     ✓ |browser (chromium)|  linux  basic.test.ts > always good <time>
+     × |browser (chromium)|  linux  basic.test.ts > works on node <time>
        → expected 'object' to be 'undefined' // Object.is equality
-     ✓ |browser (chromium)| first.test.ts > works on browser <time>
-     ✓ |browser (chromium)| second.test.ts > also good <time>
-     ✓ |node| first.test.ts > always good <time>
-     ✓ |node| first.test.ts > works on node <time>
-     × |node| first.test.ts > works on browser <time>
+     ✓ |browser (chromium)|  linux  basic.test.ts > works on browser <time>
+     ✓ |node|  macos  basic.test.ts > always good <time>
+     ✓ |node|  macos  basic.test.ts > works on node <time>
+     × |node|  macos  basic.test.ts > works on browser <time>
        → expected 'undefined' not to be 'undefined' // Object.is equality
-     ✓ |node| second.test.ts > also good <time>
-     ✓ |browser (chromium)| second.test.ts > also good <time>
-     ✓ |browser (chromium)| first.test.ts > always good <time>
-     × |browser (chromium)| first.test.ts > works on node <time>
+     ✓ |browser (chromium)|  macos  basic.test.ts > always good <time>
+     × |browser (chromium)|  macos  basic.test.ts > works on node <time>
        → expected 'object' to be 'undefined' // Object.is equality
-     ✓ |browser (chromium)| first.test.ts > works on browser <time>
+     ✓ |browser (chromium)|  macos  basic.test.ts > works on browser <time>
 
-     Test Files  4 failed | 4 passed (8)
-          Tests  4 failed | 12 passed (16)
+     Test Files  4 failed (4)
+          Tests  4 failed | 8 passed (12)
        Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)
        Per blob  <time> <time>"
   `)
@@ -792,10 +777,10 @@ test("also good", () => {})
     "
     ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 4 ⎯⎯⎯⎯⎯⎯⎯
 
-     FAIL  |node| first.test.ts > works on browser
-     FAIL  |node| first.test.ts > works on browser
+     FAIL  |node|  linux  basic.test.ts > works on browser
+     FAIL  |node|  macos  basic.test.ts > works on browser
     AssertionError: expected 'undefined' not to be 'undefined' // Object.is equality
-     ❯ first.test.ts:11:29
+     ❯ basic.test.ts:11:29
           9|
          10| test("works on browser", () => {
          11|   expect(typeof window).not.toBe('undefined')
@@ -805,14 +790,13 @@ test("also good", () => {})
 
     ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/4]⎯
 
-     FAIL  |browser (chromium)| first.test.ts > works on node
-     FAIL  |browser (chromium)| first.test.ts > works on node
+     FAIL  |browser (chromium)|  linux  basic.test.ts > works on node
     AssertionError: expected 'object' to be 'undefined' // Object.is equality
 
     Expected: "undefined"
     Received: "object"
 
-     ❯ first.test.ts:7:24
+     ❯ basic.test.ts:7:24
           5|
           6| test("works on node", () => {
           7|   expect(typeof window).toBe('undefined')
@@ -822,32 +806,56 @@ test("also good", () => {})
 
     ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[2/4]⎯
 
+     FAIL  |browser (chromium)|  macos  basic.test.ts > works on node
+    AssertionError: expected 'object' to be 'undefined' // Object.is equality
+
+    Expected: "undefined"
+    Received: "object"
+
+     ❯ basic.test.ts:7:24
+          5|
+          6| test("works on node", () => {
+          7|   expect(typeof window).toBe('undefined')
+           |                        ^
+          8| })
+          9|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[3/4]⎯
+
     "
   `)
   expect(result.errorTree({ project: true, fileLabel: true })).toMatchInlineSnapshot(`
     {
       "browser (chromium)": {
-        "first.test.ts (undefined)": {
+        "basic.test.ts (linux)": {
           "always good": "passed",
           "works on browser": "passed",
           "works on node": [
             "expected 'object' to be 'undefined' // Object.is equality",
           ],
         },
-        "second.test.ts (undefined)": {
-          "also good": "passed",
+        "basic.test.ts (macos)": {
+          "always good": "passed",
+          "works on browser": "passed",
+          "works on node": [
+            "expected 'object' to be 'undefined' // Object.is equality",
+          ],
         },
       },
       "node": {
-        "first.test.ts (undefined)": {
+        "basic.test.ts (linux)": {
           "always good": "passed",
           "works on browser": [
             "expected 'undefined' not to be 'undefined' // Object.is equality",
           ],
           "works on node": "passed",
         },
-        "second.test.ts (undefined)": {
-          "also good": "passed",
+        "basic.test.ts (macos)": {
+          "always good": "passed",
+          "works on browser": [
+            "expected 'undefined' not to be 'undefined' // Object.is equality",
+          ],
+          "works on node": "passed",
         },
       },
     }

From 24eb786f9595eb1630d08d5f1a6d4591f083f355 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:03:32 +0900
Subject: [PATCH 38/65] docs: add blobLabel docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/.vitepress/config.ts           |  4 +++
 docs/config/blob-label.md           | 45 +++++++++++++++++++++++++++++
 docs/guide/cli.md                   |  2 +-
 docs/guide/improving-performance.md |  9 +++---
 docs/guide/reporters.md             |  9 ++++--
 5 files changed, 62 insertions(+), 7 deletions(-)
 create mode 100644 docs/config/blob-label.md

diff --git a/docs/.vitepress/config.ts b/docs/.vitepress/config.ts
index d57f189de1f6..751b7f2778f4 100644
--- a/docs/.vitepress/config.ts
+++ b/docs/.vitepress/config.ts
@@ -336,6 +336,10 @@ export default ({ mode }: { mode: string }) => {
                 text: 'reporters',
                 link: '/config/reporters',
               },
+              {
+                text: 'blobLabel',
+                link: '/config/blob-label',
+              },
               {
                 text: 'outputFile',
                 link: '/config/outputfile',
diff --git a/docs/config/blob-label.md b/docs/config/blob-label.md
new file mode 100644
index 000000000000..b9b1f5c5683c
--- /dev/null
+++ b/docs/config/blob-label.md
@@ -0,0 +1,45 @@
+---
+title: blobLabel | Config
+---
+
+# blobLabel <CRoot />
+
+- **Type:** `string`
+- **CLI:** `--blobLabel=<label>`
+
+Label for the current test run. When set, the label is displayed alongside test results in the reporter output, and stored in the blob when using [`--reporter=blob`](/guide/reporters#blob-reporter).
+
+During [`--merge-reports`](/guide/cli#merge-reports), results from the same test files with different labels are kept as separate entries. The label is also included in the default blob output filename (e.g. `blob-linux.json`) to avoid collisions between runs on different machines.
+
+## Example
+
+::: code-group
+```bash [CLI]
+# on linux
+vitest run --reporter=blob --blobLabel=linux
+
+# on macos
+vitest run --reporter=blob --blobLabel=macos
+```
+```ts [vitest.config.ts]
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    blobLabel: process.env.OS_LABEL,
+    reporters: ['blob'],
+  },
+})
+```
+:::
+
+When merging, each label is displayed as a separate entry in the reporter output:
+
+```sh
+vitest --merge-reports
+
+ ✓  linux  src/basic.test.ts (2 tests)
+ ✓  macos  src/basic.test.ts (2 tests)
+```
+
+See [Blob Reporter](/guide/reporters#blob-reporter) and the [CI setup guide](/guide/improving-performance#cross-platform-sharding) for a full example.
diff --git a/docs/guide/cli.md b/docs/guide/cli.md
index e1a16c45193b..992621645e4b 100644
--- a/docs/guide/cli.md
+++ b/docs/guide/cli.md
@@ -225,7 +225,7 @@ You cannot use this option with `--watch` enabled (enabled in dev by default).
 :::
 
 ::: tip
-If `--reporter=blob` is used without an output file, the default path will include the current shard config to avoid collisions with other Vitest processes.
+If `--reporter=blob` is used without an output file, the default path will include the current shard config and [`blobLabel`](/config/blob-label) to avoid collisions with other Vitest processes.
 :::
 
 ### merge-reports
diff --git a/docs/guide/improving-performance.md b/docs/guide/improving-performance.md
index efbbc804d3ac..d9835b23b40d 100644
--- a/docs/guide/improving-performance.md
+++ b/docs/guide/improving-performance.md
@@ -144,9 +144,10 @@ on:
       - main
 jobs:
   tests:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ubuntu-latest, macos-latest]
         shardIndex: [1, 2, 3, 4]
         shardTotal: [4]
     steps:
@@ -162,13 +163,13 @@ jobs:
         run: pnpm i
 
       - name: Run tests
-        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }}
+        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --blobLabel=${{ matrix.os }}
 
       - name: Upload blob report to GitHub Actions Artifacts
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@v4
         with:
-          name: blob-report-${{ matrix.shardIndex }}
+          name: blob-report-${{ matrix.os }}-${{ matrix.shardIndex }}
           path: .vitest-reports/*
           include-hidden-files: true
           retention-days: 1
@@ -177,7 +178,7 @@ jobs:
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@v4
         with:
-          name: blob-attachments-${{ matrix.shardIndex }}
+          name: blob-attachments-${{ matrix.os }}-${{ matrix.shardIndex }}
           path: .vitest-attachments/**
           include-hidden-files: true
           retention-days: 1
diff --git a/docs/guide/reporters.md b/docs/guide/reporters.md
index 95612f070208..aa8a53d21720 100644
--- a/docs/guide/reporters.md
+++ b/docs/guide/reporters.md
@@ -670,13 +670,18 @@ By default, stores all results in `.vitest-reports` folder, but can be overridde
 npx vitest --reporter=blob --outputFile=reports/blob-1.json
 ```
 
-We recommend using this reporter if you are running Vitest on different machines with the [`--shard`](/guide/cli#shard) flag.
-All blob reports can be merged into any report by using `--merge-reports` command at the end of your CI pipeline:
+We recommend using this reporter if you are running Vitest on different machines with the [`--shard`](/guide/cli#shard) flag or across multiple environments (e.g., linux/macos/windows). All blob reports can be merged into any report by using `--merge-reports` command at the end of your CI pipeline:
 
 ```bash
 npx vitest --merge-reports=reports --reporter=json --reporter=default
 ```
 
+When running the same tests across multiple environments, use the `--blobLabel` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
+
+```bash
+vitest run --reporter=blob --blobLabel=linux
+```
+
 Blob reporter output doesn't include file-based [attachments](/api/advanced/artifacts.html#testattachment).
 Make sure to merge [`attachmentsDir`](/config/attachmentsdir) separately alongside blob reports on CI when using this feature.
 

From 40aa216ef250081139478c3425d02301b7c32784 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:05:21 +0900
Subject: [PATCH 39/65] docs: fix anchor link in blob-label.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/config/blob-label.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/config/blob-label.md b/docs/config/blob-label.md
index b9b1f5c5683c..833a2b6d47d6 100644
--- a/docs/config/blob-label.md
+++ b/docs/config/blob-label.md
@@ -42,4 +42,4 @@ vitest --merge-reports
  ✓  macos  src/basic.test.ts (2 tests)
 ```
 
-See [Blob Reporter](/guide/reporters#blob-reporter) and the [CI setup guide](/guide/improving-performance#cross-platform-sharding) for a full example.
+See [Blob Reporter](/guide/reporters#blob-reporter) and the [CI setup guide](/guide/improving-performance#sharding) for a full example.

From 1da3f5cf9ac9815dba93bf9b1b1cc2eded22b8f8 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:11:10 +0900
Subject: [PATCH 40/65] chore: lint

---
 docs/config/blob-label.md                     | 5 ++++-
 test/cli/test/reporters/merge-reports.test.ts | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/docs/config/blob-label.md b/docs/config/blob-label.md
index 833a2b6d47d6..2663a0fcc379 100644
--- a/docs/config/blob-label.md
+++ b/docs/config/blob-label.md
@@ -14,6 +14,7 @@ During [`--merge-reports`](/guide/cli#merge-reports), results from the same test
 ## Example
 
 ::: code-group
+
 ```bash [CLI]
 # on linux
 vitest run --reporter=blob --blobLabel=linux
@@ -21,16 +22,18 @@ vitest run --reporter=blob --blobLabel=linux
 # on macos
 vitest run --reporter=blob --blobLabel=macos
 ```
+
 ```ts [vitest.config.ts]
 import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
   test: {
-    blobLabel: process.env.OS_LABEL,
+    blobLabel: `${process.platform}-${process.versions.node}`,
     reporters: ['blob'],
   },
 })
 ```
+
 :::
 
 When merging, each label is displayed as a separate entry in the reporter output:
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 6ac90820fecf..de0cc870883b 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -654,7 +654,7 @@ test("works on node", () => {
 test("works on browser", () => {
   expect(typeof window).not.toBe('undefined')
 })
-`
+`,
   })
   const baseConfig: RunVitestConfig = {
     root,

From a6dc75cb01219b611aee0028ada603291c4efacf Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:11:37 +0900
Subject: [PATCH 41/65] docs: tweak

---
 docs/config/blob-label.md | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/docs/config/blob-label.md b/docs/config/blob-label.md
index 2663a0fcc379..141db6287d4c 100644
--- a/docs/config/blob-label.md
+++ b/docs/config/blob-label.md
@@ -13,16 +13,15 @@ During [`--merge-reports`](/guide/cli#merge-reports), results from the same test
 
 ## Example
 
-::: code-group
+Run with a label on each platform:
 
-```bash [CLI]
-# on linux
+```bash
 vitest run --reporter=blob --blobLabel=linux
-
-# on macos
 vitest run --reporter=blob --blobLabel=macos
 ```
 
+Or set it via config, typically driven by an environment variable in CI:
+
 ```ts [vitest.config.ts]
 import { defineConfig } from 'vitest/config'
 
@@ -34,8 +33,6 @@ export default defineConfig({
 })
 ```
 
-:::
-
 When merging, each label is displayed as a separate entry in the reporter output:
 
 ```sh

From 296f3c7edf2b9458c123ec6a75747ede2f36f45c Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:15:05 +0900
Subject: [PATCH 42/65] refactor: rename blobLabel -> label

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 packages/runner/src/collect.ts                         |  2 +-
 packages/runner/src/types/runner.ts                    |  2 +-
 packages/runner/src/utils/collect.ts                   |  6 +++---
 packages/ui/client/components/FileDetails.vue          |  4 ++--
 packages/ui/client/components/explorer/Explorer.vue    |  2 +-
 .../ui/client/components/explorer/ExplorerItem.vue     |  6 +++---
 packages/ui/client/components/views/ViewTestReport.vue |  2 +-
 packages/ui/client/composables/explorer/types.ts       |  2 +-
 packages/ui/client/composables/explorer/utils.ts       |  4 ++--
 packages/vitest/src/node/cli/cli-config.ts             |  4 ++--
 packages/vitest/src/node/config/serializeConfig.ts     |  2 +-
 packages/vitest/src/node/project.ts                    |  2 +-
 packages/vitest/src/node/reporters/base.ts             | 10 +++++-----
 packages/vitest/src/node/reporters/blob.ts             |  2 +-
 packages/vitest/src/node/reporters/summary.ts          |  8 ++++----
 packages/vitest/src/node/state.ts                      |  2 +-
 packages/vitest/src/node/test-specification.ts         |  2 +-
 packages/vitest/src/node/types/config.ts               |  8 ++++----
 packages/vitest/src/runtime/config.ts                  |  2 +-
 packages/vitest/src/types/global.ts                    |  2 +-
 packages/ws-client/src/state.ts                        |  2 +-
 test/cli/test/reporters/merge-reports.test.ts          |  8 ++++----
 test/cli/vitest.config.ts                              |  2 +-
 test/core/vite.config.ts                               |  2 +-
 test/test-utils/index.ts                               |  2 +-
 25 files changed, 45 insertions(+), 45 deletions(-)

diff --git a/packages/runner/src/collect.ts b/packages/runner/src/collect.ts
index 6bb5002c7207..dc872eed8a52 100644
--- a/packages/runner/src/collect.ts
+++ b/packages/runner/src/collect.ts
@@ -47,7 +47,7 @@ export async function collectTests(
 
         const fileTags: string[] = typeof spec === 'string' ? [] : (spec.fileTags || [])
 
-        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, { blobLabel: config.blobLabel })
+        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, { label: config.label })
         file.tags = fileTags
         file.shuffle = config.sequence.shuffle
 
diff --git a/packages/runner/src/types/runner.ts b/packages/runner/src/types/runner.ts
index d45645b008e4..05bd94b82fde 100644
--- a/packages/runner/src/types/runner.ts
+++ b/packages/runner/src/types/runner.ts
@@ -45,7 +45,7 @@ export interface VitestRunnerConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  blobLabel: string | undefined
+  label: string | undefined
 }
 
 /**
diff --git a/packages/runner/src/utils/collect.ts b/packages/runner/src/utils/collect.ts
index 19b5b28ca7d1..a7b9cea52e29 100644
--- a/packages/runner/src/utils/collect.ts
+++ b/packages/runner/src/utils/collect.ts
@@ -199,7 +199,7 @@ export function createFileTask(
   projectName: string | undefined,
   pool?: string,
   viteEnvironment?: string,
-  meta?: { typecheck?: boolean; blobLabel?: string },
+  meta?: { typecheck?: boolean; label?: string },
 ): File {
   const path = relative(root, filepath)
   const file: File = {
@@ -229,13 +229,13 @@ export function createFileTask(
 export function generateFileHash(
   file: string,
   projectName: string | undefined,
-  meta?: { typecheck?: boolean; blobLabel?: string },
+  meta?: { typecheck?: boolean; label?: string },
 ): string {
   const seed = [
     file,
     projectName || '',
     meta?.typecheck ? '__typecheck__' : '',
-    meta?.blobLabel || '',
+    meta?.label || '',
   ].join('\0')
   return generateHash(seed)
 }
diff --git a/packages/ui/client/components/FileDetails.vue b/packages/ui/client/components/FileDetails.vue
index 4a85ef12344d..40117e2fa514 100644
--- a/packages/ui/client/components/FileDetails.vue
+++ b/packages/ui/client/components/FileDetails.vue
@@ -60,7 +60,7 @@ const isTypecheck = computed(() => {
   return !!current.value?.meta?.typecheck
 })
 
-const blobLabel = computed(() => current.value?.meta?.blobLabel)
+const label = computed(() => current.value?.meta?.label)
 
 function open() {
   const filePath = current.value?.filepath
@@ -208,7 +208,7 @@ const tags = computed(() => {
       <div p="2" h-10 flex="~ gap-2" items-center bg-header border="b base">
         <StatusIcon :state="current.result?.state" :mode="current.mode" :failed-snapshot="failedSnapshot" />
         <div v-if="isTypecheck" v-tooltip.bottom="'This is a typecheck test. It won\'t report results of the runtime tests'" class="i-logos:typescript-icon" flex-shrink-0 />
-        <span v-if="blobLabel" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ blobLabel }}</span>
+        <span v-if="label" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ label }}</span>
         <span
           v-if="current?.file.projectName"
           class="rounded-full py-0.5 px-2 text-xs font-light"
diff --git a/packages/ui/client/components/explorer/Explorer.vue b/packages/ui/client/components/explorer/Explorer.vue
index 4bdd13ab7bae..e196c1bef592 100644
--- a/packages/ui/client/components/explorer/Explorer.vue
+++ b/packages/ui/client/components/explorer/Explorer.vue
@@ -331,7 +331,7 @@ const {
                 :indent="item.indent"
                 :name="item.name"
                 :typecheck="item.typecheck === true"
-                :blob-label="item.blobLabel"
+                :label="item.label"
                 :project-name="item.projectName ?? ''"
                 :project-name-color="item.projectNameColor ?? ''"
                 :state="item.state"
diff --git a/packages/ui/client/components/explorer/ExplorerItem.vue b/packages/ui/client/components/explorer/ExplorerItem.vue
index 007702d3a3a7..d237ba9c7ebb 100644
--- a/packages/ui/client/components/explorer/ExplorerItem.vue
+++ b/packages/ui/client/components/explorer/ExplorerItem.vue
@@ -25,7 +25,7 @@ const {
   opened,
   expandable,
   typecheck,
-  blobLabel,
+  label,
   type,
   disableTaskLocation,
   onItemClick,
@@ -36,7 +36,7 @@ const {
   name: string
   indent: number
   typecheck?: boolean
-  blobLabel?: string
+  label?: string
   duration?: number
   slow?: boolean
   state?: TaskState
@@ -218,7 +218,7 @@ const tagsBgGradient = computed(() => {
     <StatusIcon :state="state" :mode="task.mode" :failed-snapshot="failedSnapshot" w-4 />
     <div flex items-baseline gap-2 overflow-hidden>
       <div v-if="type === 'file' && typecheck" v-tooltip.bottom="'This is a typecheck test. It won\'t report results of the runtime tests'" class="i-logos:typescript-icon" flex-shrink-0 />
-      <span v-if="type === 'file' && blobLabel" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ blobLabel }}</span>
+      <span v-if="type === 'file' && label" class="rounded-sm px-1 text-xs font-light bg-cyan-500/20 text-cyan-700 dark:text-cyan-300" flex-shrink-0>{{ label }}</span>
       <span text-sm truncate font-light>
         <span v-if="type === 'file' && projectName" class="rounded-full py-0.5 px-2 mr-1 text-xs" :style="{ backgroundColor: projectNameColor, color: projectNameTextColor }">
           {{ projectName }}
diff --git a/packages/ui/client/components/views/ViewTestReport.vue b/packages/ui/client/components/views/ViewTestReport.vue
index 9c55351132b1..77c0146e1d4f 100644
--- a/packages/ui/client/components/views/ViewTestReport.vue
+++ b/packages/ui/client/components/views/ViewTestReport.vue
@@ -25,7 +25,7 @@ const failed = computed(() => {
 const kWellKnownMeta = new Set([
   'benchmark',
   'typecheck',
-  'blobLabel',
+  'label',
 ])
 const meta = computed(() => {
   return Object.entries(props.test.meta).filter(([name]) => {
diff --git a/packages/ui/client/composables/explorer/types.ts b/packages/ui/client/composables/explorer/types.ts
index 585806b9afc2..16cc9305d3b1 100644
--- a/packages/ui/client/composables/explorer/types.ts
+++ b/packages/ui/client/composables/explorer/types.ts
@@ -63,7 +63,7 @@ export interface FileTreeNode extends ParentTreeNode {
   type: 'file'
   filepath: string
   typecheck: boolean | undefined
-  blobLabel?: string
+  label?: string
   projectName?: string
   projectNameColor: string
   collectDuration?: number
diff --git a/packages/ui/client/composables/explorer/utils.ts b/packages/ui/client/composables/explorer/utils.ts
index 82ced02fa47d..9ad93af19053 100644
--- a/packages/ui/client/composables/explorer/utils.ts
+++ b/packages/ui/client/composables/explorer/utils.ts
@@ -84,7 +84,7 @@ export function createOrUpdateFileNode(
 
   if (fileNode) {
     fileNode.typecheck = !!file.meta && 'typecheck' in file.meta
-    fileNode.blobLabel = file.meta?.blobLabel
+    fileNode.label = file.meta?.label
     fileNode.state = file.result?.state
     fileNode.mode = file.mode
     fileNode.duration = typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined
@@ -107,7 +107,7 @@ export function createOrUpdateFileNode(
       children: new Set(),
       tasks: [],
       typecheck: !!file.meta && 'typecheck' in file.meta,
-      blobLabel: file.meta?.blobLabel,
+      label: file.meta?.label,
       indent: 0,
       duration: typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined,
       slow: false,
diff --git a/packages/vitest/src/node/cli/cli-config.ts b/packages/vitest/src/node/cli/cli-config.ts
index b5f8fc5c7a6f..8769704b5d09 100644
--- a/packages/vitest/src/node/cli/cli-config.ts
+++ b/packages/vitest/src/node/cli/cli-config.ts
@@ -830,8 +830,8 @@ export const cliOptionsConfig: VitestCLIOptions = {
     description: 'List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.',
     argument: '[type]',
   },
-  blobLabel: {
-    description: 'Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--blob-label=linux`).',
+  label: {
+    description: 'Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--label=linux`).',
     argument: '<label>',
   },
   clearCache: {
diff --git a/packages/vitest/src/node/config/serializeConfig.ts b/packages/vitest/src/node/config/serializeConfig.ts
index 69625aa68b70..6d388bc9b253 100644
--- a/packages/vitest/src/node/config/serializeConfig.ts
+++ b/packages/vitest/src/node/config/serializeConfig.ts
@@ -143,7 +143,7 @@ export function serializeConfig(project: TestProject): SerializedConfig {
     tags: config.tags || [],
     tagsFilter: config.tagsFilter,
     strictTags: config.strictTags ?? true,
-    blobLabel: config.blobLabel,
+    label: config.label,
     slowTestThreshold:
       config.slowTestThreshold
       ?? globalConfig.slowTestThreshold
diff --git a/packages/vitest/src/node/project.ts b/packages/vitest/src/node/project.ts
index db867f815b5e..d44970672b4e 100644
--- a/packages/vitest/src/node/project.ts
+++ b/packages/vitest/src/node/project.ts
@@ -555,7 +555,7 @@ export class TestProject {
       server.config,
     )
     this._config.api.token = this.vitest.config.api.token
-    this._config.blobLabel = this.vitest.config.blobLabel
+    this._config.label = this.vitest.config.label
     this._setHash()
     for (const _providedKey in this.config.provide) {
       const providedKey = _providedKey as keyof ProvidedContext
diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index d2782ee1fcfc..9d2f32f7a935 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -336,9 +336,9 @@ export abstract class BaseReporter implements Reporter {
     }
 
     // TODO: show only during --merge-reports?
-    const blobLabel = entity.task.file.meta.blobLabel
-    if (blobLabel) {
-      title += ` ${c.bgCyan(c.bold(` ${blobLabel} `))}`
+    const label = entity.task.file.meta.label
+    if (label) {
+      title += ` ${c.bgCyan(c.bold(` ${label} `))}`
     }
 
     return title
@@ -942,9 +942,9 @@ export abstract class BaseReporter implements Reporter {
           name += c.dim(` [ ${this.relative(filepath)} ]`)
         }
 
-        const blobLabel = task.file?.meta?.blobLabel
+        const label = task.file?.meta?.label
         this.ctx.logger.error(
-          `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${blobLabel ? `${c.bgCyan(c.bold(` ${blobLabel} `))} ` : ''}${name}`,
+          `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${label ? `${c.bgCyan(c.bold(` ${label} `))} ` : ''}${name}`,
         )
       }
 
diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index b4f3df28a6ce..f352035124fe 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -50,7 +50,7 @@ export class BlobReporter implements Reporter {
       = this.options.outputFile ?? getOutputFile(this.ctx.config, 'blob')
     if (!outputFile) {
       const shard = this.ctx.config.shard
-      const label = this.ctx.config.blobLabel
+      const label = this.ctx.config.label
       const suffix = [label, shard && `${shard.index}-${shard.count}`].filter(Boolean).join('-')
       outputFile = suffix ? `.vitest-reports/blob-${suffix}.json` : '.vitest-reports/blob.json'
     }
diff --git a/packages/vitest/src/node/reporters/summary.ts b/packages/vitest/src/node/reporters/summary.ts
index 9b22e6eb0d28..414af88d1c78 100644
--- a/packages/vitest/src/node/reporters/summary.ts
+++ b/packages/vitest/src/node/reporters/summary.ts
@@ -40,7 +40,7 @@ interface RunningModule extends Pick<Counter, 'total' | 'completed'> {
   tests: Map<TestCase['id'], SlowTask>
   // TODO: keep it in one meta?
   typecheck: boolean
-  blobLabel?: string
+  label?: string
 }
 
 /**
@@ -291,12 +291,12 @@ export class SummaryReporter implements Reporter {
 
     for (const testFile of Array.from(this.runningModules.values()).sort(sortRunningModules)) {
       const typecheck = testFile.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
-      const blobLabel = testFile.blobLabel ? `${c.bgCyan(c.bold(` ${testFile.blobLabel} `))} ` : ''
+      const label = testFile.label ? `${c.bgCyan(c.bold(` ${testFile.label} `))} ` : ''
       summary.push(
         c.bold(c.yellow(` ${F_POINTER} `))
         + formatProjectName({ name: testFile.projectName, color: testFile.projectColor })
         + typecheck
-        + blobLabel
+        + label
         + testFile.filename
         + c.dim(!testFile.completed && !testFile.total
           ? ' [queued]'
@@ -403,6 +403,6 @@ function initializeStats(module: TestModule): RunningModule {
     projectColor: module.project.color,
     tests: new Map(),
     typecheck: !!module.task.meta.typecheck,
-    blobLabel: module.task.meta.blobLabel,
+    label: module.task.meta.label,
   }
 }
diff --git a/packages/vitest/src/node/state.ts b/packages/vitest/src/node/state.ts
index 853b93065f1d..0379976fa1dd 100644
--- a/packages/vitest/src/node/state.ts
+++ b/packages/vitest/src/node/state.ts
@@ -148,7 +148,7 @@ export class StateManager {
       const currentFile = existing.find(
         i => i.projectName === file.projectName
           && i.meta.typecheck === file.meta.typecheck
-          && i.meta.blobLabel === file.meta.blobLabel,
+          && i.meta.label === file.meta.label,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index af0094acf338..04312bf9ecb6 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -62,7 +62,7 @@ export class TestSpecification {
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      meta ?? { typecheck: pool === 'typescript', blobLabel: project.config.blobLabel },
+      meta ?? { typecheck: pool === 'typescript', label: project.config.label },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index 50fbefac5607..ece624b74c66 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -968,9 +968,9 @@ export interface InlineConfig {
   /**
    * Label to disambiguate the same test file when run under different conditions
    * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and
-   * `File.meta.blobLabel` so that state treats each label as a distinct entry.
+   * `File.meta.label` so that state treats each label as a distinct entry.
    */
-  blobLabel?: string
+  label?: string
 }
 
 export interface TypecheckConfig {
@@ -1150,7 +1150,7 @@ export interface ResolvedConfig
     | 'vmMemoryLimit'
     | 'fileParallelism'
     | 'tagsFilter'
-    | 'blobLabel'
+    | 'label'
   > {
   mode: VitestRunMode
 
@@ -1222,7 +1222,7 @@ export interface ResolvedConfig
   vmMemoryLimit?: UserConfig['vmMemoryLimit']
   dumpDir?: string
   tagsFilter?: string[]
-  blobLabel?: string
+  label?: string
 
   experimental: Omit<Required<UserConfig>['experimental'], 'importDurations'> & {
     importDurations: {
diff --git a/packages/vitest/src/runtime/config.ts b/packages/vitest/src/runtime/config.ts
index b37417eb2f59..f1b610d123fc 100644
--- a/packages/vitest/src/runtime/config.ts
+++ b/packages/vitest/src/runtime/config.ts
@@ -145,7 +145,7 @@ export interface SerializedConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  blobLabel: string | undefined
+  label: string | undefined
   slowTestThreshold: number | undefined
   isAgent: boolean
 }
diff --git a/packages/vitest/src/types/global.ts b/packages/vitest/src/types/global.ts
index 918d59fa7d06..5c62bf81efc7 100644
--- a/packages/vitest/src/types/global.ts
+++ b/packages/vitest/src/types/global.ts
@@ -111,7 +111,7 @@ declare module '@vitest/runner' {
     typecheck?: boolean
     benchmark?: boolean
     // TODO: rename it `label`? also accomodate `label: "__typecheck__"`?
-    blobLabel?: string
+    label?: string
   }
 
   interface File {
diff --git a/packages/ws-client/src/state.ts b/packages/ws-client/src/state.ts
index e1e9f8ca3492..981a25d7a823 100644
--- a/packages/ws-client/src/state.ts
+++ b/packages/ws-client/src/state.ts
@@ -48,7 +48,7 @@ export class StateManager {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
       const currentFile = existing.find(
-        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.blobLabel === file.meta.blobLabel,
+        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.label === file.meta.label,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index de0cc870883b..e59f7e746a5b 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -508,7 +508,7 @@ test("macos only", () => {})
   const result1 = await runVitest({
     root,
     globals: true,
-    blobLabel: 'linux',
+    label: 'linux',
     reporters: 'blob',
   }, ['first', 'second'])
   expect(result1.stderr).toMatchInlineSnapshot(`""`)
@@ -530,7 +530,7 @@ test("macos only", () => {})
   const result2 = await runVitest({
     root,
     globals: true,
-    blobLabel: 'macos',
+    label: 'macos',
     reporters: 'blob',
   }, ['first', 'third'])
   expect(result2.stderr).toMatchInlineSnapshot(`""`)
@@ -692,7 +692,7 @@ test("works on browser", () => {
   }
   const result1 = await runVitest({
     ...baseConfig,
-    blobLabel: 'linux',
+    label: 'linux',
     reporters: 'blob',
   })
   expect(result1.stderr).toMatchInlineSnapshot(`""`)
@@ -720,7 +720,7 @@ test("works on browser", () => {
   `)
   const result2 = await runVitest({
     ...baseConfig,
-    blobLabel: 'macos',
+    label: 'macos',
     reporters: 'blob',
   })
   expect(result2.stderr).toMatchInlineSnapshot(`""`)
diff --git a/test/cli/vitest.config.ts b/test/cli/vitest.config.ts
index 756799522835..e714487f3904 100644
--- a/test/cli/vitest.config.ts
+++ b/test/cli/vitest.config.ts
@@ -10,7 +10,7 @@ export default defineConfig({
         ? [['blob', {}] as any]
         : []),
     ],
-    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
+    label: process.env.VITEST_CI_BLOB_LABEL,
     testTimeout: 60_000,
     isolate: false,
     fileParallelism: false,
diff --git a/test/core/vite.config.ts b/test/core/vite.config.ts
index 85d5d12c8a75..4d072f8e6e16 100644
--- a/test/core/vite.config.ts
+++ b/test/core/vite.config.ts
@@ -133,7 +133,7 @@ export default defineConfig({
         ? [['blob']]
         : []),
     ],
-    blobLabel: process.env.VITEST_CI_BLOB_LABEL,
+    label: process.env.VITEST_CI_BLOB_LABEL,
     testNamePattern: '^((?!does not include test that).)*$',
     coverage: {
       provider: 'istanbul',
diff --git a/test/test-utils/index.ts b/test/test-utils/index.ts
index 4f7ba358a470..c22f53f4aadc 100644
--- a/test/test-utils/index.ts
+++ b/test/test-utils/index.ts
@@ -619,7 +619,7 @@ export function buildErrorTree(testModules: TestModule[], options?: BuildErrorTr
       }
       return moduleChildren
     },
-    options?.fileLabel ? module => `${module.relativeModuleId} (${module.meta().blobLabel})` : undefined,
+    options?.fileLabel ? module => `${module.relativeModuleId} (${module.meta().label})` : undefined,
   )
 }
 

From 01d4f352e07d4cfe65929ff40e74bf6ed90da86b Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:16:17 +0900
Subject: [PATCH 43/65] docs: rename blobLabel -> label

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/.vitepress/config.ts               |  4 ++--
 docs/config/{blob-label.md => label.md} | 12 ++++++------
 docs/guide/cli-generated.md             |  8 ++++----
 docs/guide/cli.md                       |  2 +-
 docs/guide/improving-performance.md     |  2 +-
 docs/guide/reporters.md                 |  4 ++--
 6 files changed, 16 insertions(+), 16 deletions(-)
 rename docs/config/{blob-label.md => label.md} (82%)

diff --git a/docs/.vitepress/config.ts b/docs/.vitepress/config.ts
index 751b7f2778f4..1cbeb73b5fc7 100644
--- a/docs/.vitepress/config.ts
+++ b/docs/.vitepress/config.ts
@@ -337,8 +337,8 @@ export default ({ mode }: { mode: string }) => {
                 link: '/config/reporters',
               },
               {
-                text: 'blobLabel',
-                link: '/config/blob-label',
+                text: 'label',
+                link: '/config/label',
               },
               {
                 text: 'outputFile',
diff --git a/docs/config/blob-label.md b/docs/config/label.md
similarity index 82%
rename from docs/config/blob-label.md
rename to docs/config/label.md
index 141db6287d4c..8e9954f19ffa 100644
--- a/docs/config/blob-label.md
+++ b/docs/config/label.md
@@ -1,11 +1,11 @@
 ---
-title: blobLabel | Config
+title: label | Config
 ---
 
-# blobLabel <CRoot />
+# label <CRoot />
 
 - **Type:** `string`
-- **CLI:** `--blobLabel=<label>`
+- **CLI:** `--label=<label>`
 
 Label for the current test run. When set, the label is displayed alongside test results in the reporter output, and stored in the blob when using [`--reporter=blob`](/guide/reporters#blob-reporter).
 
@@ -16,8 +16,8 @@ During [`--merge-reports`](/guide/cli#merge-reports), results from the same test
 Run with a label on each platform:
 
 ```bash
-vitest run --reporter=blob --blobLabel=linux
-vitest run --reporter=blob --blobLabel=macos
+vitest run --reporter=blob --label=linux
+vitest run --reporter=blob --label=macos
 ```
 
 Or set it via config, typically driven by an environment variable in CI:
@@ -27,7 +27,7 @@ import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
   test: {
-    blobLabel: `${process.platform}-${process.versions.node}`,
+    label: `${process.platform}-${process.versions.node}`,
     reporters: ['blob'],
   },
 })
diff --git a/docs/guide/cli-generated.md b/docs/guide/cli-generated.md
index cdc565068c84..27fcc9af7b05 100644
--- a/docs/guide/cli-generated.md
+++ b/docs/guide/cli-generated.md
@@ -875,12 +875,12 @@ Start Vitest without running tests. Tests will be running only on change. If bro
 
 List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.
 
-### blobLabel
+### label
 
-- **CLI:** `--blobLabel <label>`
-- **Config:** [blobLabel](/config/bloblabel)
+- **CLI:** `--label <label>`
+- **Config:** [label](/config/label)
 
-Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--blob-label=linux`).
+Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--label=linux`).
 
 ### clearCache
 
diff --git a/docs/guide/cli.md b/docs/guide/cli.md
index 992621645e4b..32fcfff11e3c 100644
--- a/docs/guide/cli.md
+++ b/docs/guide/cli.md
@@ -225,7 +225,7 @@ You cannot use this option with `--watch` enabled (enabled in dev by default).
 :::
 
 ::: tip
-If `--reporter=blob` is used without an output file, the default path will include the current shard config and [`blobLabel`](/config/blob-label) to avoid collisions with other Vitest processes.
+If `--reporter=blob` is used without an output file, the default path will include the current shard config and [`label`](/config/label) to avoid collisions with other Vitest processes.
 :::
 
 ### merge-reports
diff --git a/docs/guide/improving-performance.md b/docs/guide/improving-performance.md
index d9835b23b40d..d3b4b5e15a63 100644
--- a/docs/guide/improving-performance.md
+++ b/docs/guide/improving-performance.md
@@ -163,7 +163,7 @@ jobs:
         run: pnpm i
 
       - name: Run tests
-        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --blobLabel=${{ matrix.os }}
+        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --label=${{ matrix.os }}
 
       - name: Upload blob report to GitHub Actions Artifacts
         if: ${{ !cancelled() }}
diff --git a/docs/guide/reporters.md b/docs/guide/reporters.md
index aa8a53d21720..dade791f763e 100644
--- a/docs/guide/reporters.md
+++ b/docs/guide/reporters.md
@@ -676,10 +676,10 @@ We recommend using this reporter if you are running Vitest on different machines
 npx vitest --merge-reports=reports --reporter=json --reporter=default
 ```
 
-When running the same tests across multiple environments, use the `--blobLabel` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
+When running the same tests across multiple environments, use the `--label` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
 
 ```bash
-vitest run --reporter=blob --blobLabel=linux
+vitest run --reporter=blob --label=linux
 ```
 
 Blob reporter output doesn't include file-based [attachments](/api/advanced/artifacts.html#testattachment).

From 17f3a281fcc3b9642d70a53de0d5091b2f391f2d Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:47:48 +0900
Subject: [PATCH 44/65] chore: remove todo

---
 packages/vitest/src/node/types/config.ts | 7 +------
 packages/vitest/src/types/global.ts      | 1 -
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index ece624b74c66..92a2ecbdd52a 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -962,13 +962,8 @@ export interface InlineConfig {
    */
   strictTags?: boolean
 
-  // TODO:
-  // move to blob reporter level option? but this influences the entire test run.
-  // or just label: string?
   /**
-   * Label to disambiguate the same test file when run under different conditions
-   * (e.g. different OSes in a merge-reports workflow). Encoded into `File.id` and
-   * `File.meta.label` so that state treats each label as a distinct entry.
+   * Label to disambiguate the same test file when merging blob reports from different environments
    */
   label?: string
 }
diff --git a/packages/vitest/src/types/global.ts b/packages/vitest/src/types/global.ts
index 5c62bf81efc7..2397bdf2f6be 100644
--- a/packages/vitest/src/types/global.ts
+++ b/packages/vitest/src/types/global.ts
@@ -110,7 +110,6 @@ declare module '@vitest/runner' {
   interface TaskMeta {
     typecheck?: boolean
     benchmark?: boolean
-    // TODO: rename it `label`? also accomodate `label: "__typecheck__"`?
     label?: string
   }
 

From 41853bb6e83263ac55947e252fc170726a0ac773 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:48:45 +0900
Subject: [PATCH 45/65] chore: resolved todo

---
 packages/vitest/src/node/reporters/base.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index 9d2f32f7a935..3ce0258152a8 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,7 +335,6 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
-    // TODO: show only during --merge-reports?
     const label = entity.task.file.meta.label
     if (label) {
       title += ` ${c.bgCyan(c.bold(` ${label} `))}`

From 34de287ff8ea2b6d28bdf33e32cb749f03177e22 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:53:17 +0900
Subject: [PATCH 46/65] refactor: use task.meta directly in RunningModule

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 packages/vitest/src/node/reporters/summary.ts | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/packages/vitest/src/node/reporters/summary.ts b/packages/vitest/src/node/reporters/summary.ts
index 414af88d1c78..01c005c0d0b8 100644
--- a/packages/vitest/src/node/reporters/summary.ts
+++ b/packages/vitest/src/node/reporters/summary.ts
@@ -38,9 +38,7 @@ interface RunningModule extends Pick<Counter, 'total' | 'completed'> {
   projectColor: TestModule['project']['color']
   hook?: Omit<SlowTask, 'hook'>
   tests: Map<TestCase['id'], SlowTask>
-  // TODO: keep it in one meta?
-  typecheck: boolean
-  label?: string
+  meta: TestModule['task']['meta']
 }
 
 /**
@@ -290,8 +288,8 @@ export class SummaryReporter implements Reporter {
     const summary = ['']
 
     for (const testFile of Array.from(this.runningModules.values()).sort(sortRunningModules)) {
-      const typecheck = testFile.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
-      const label = testFile.label ? `${c.bgCyan(c.bold(` ${testFile.label} `))} ` : ''
+      const typecheck = testFile.meta.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
+      const label = testFile.meta.label ? `${c.bgCyan(c.bold(` ${testFile.meta.label} `))} ` : ''
       summary.push(
         c.bold(c.yellow(` ${F_POINTER} `))
         + formatProjectName({ name: testFile.projectName, color: testFile.projectColor })
@@ -402,7 +400,6 @@ function initializeStats(module: TestModule): RunningModule {
     projectName: module.project.name,
     projectColor: module.project.color,
     tests: new Map(),
-    typecheck: !!module.task.meta.typecheck,
-    label: module.task.meta.label,
+    meta: module.task.meta,
   }
 }

From a4c18a527870e5c4256514c2de0c93ac4436456c Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Tue, 31 Mar 2026 18:55:49 +0900
Subject: [PATCH 47/65] refactor: use createFileTask in typecheck collect

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 packages/vitest/src/typecheck/collect.ts | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/packages/vitest/src/typecheck/collect.ts b/packages/vitest/src/typecheck/collect.ts
index 67912e72ac52..213512002293 100644
--- a/packages/vitest/src/typecheck/collect.ts
+++ b/packages/vitest/src/typecheck/collect.ts
@@ -3,13 +3,12 @@ import type { Rollup } from 'vite'
 import type { TestProject } from '../node/project'
 import {
   calculateSuiteHash,
+  createFileTask,
   createTaskName,
-  generateFileHash,
   interpretTaskModes,
   someTasksAreOnly,
 } from '@vitest/runner/utils'
 import { ancestor as walkAst } from 'acorn-walk'
-import { relative } from 'pathe'
 import { parseAstAsync } from 'vite'
 
 interface ParsedFile extends File {
@@ -53,22 +52,19 @@ export async function collectTests(
     return null
   }
   const ast = await parseAstAsync(request.code)
-  const testFilepath = relative(ctx.config.root, filepath)
   const projectName = ctx.name
-  // TODO: use createFileTask directly?
   const file: ParsedFile = {
-    filepath,
-    type: 'suite',
-    id: generateFileHash(testFilepath, projectName, { typecheck: true }),
-    name: testFilepath,
-    fullName: testFilepath,
-    mode: 'run',
-    tasks: [],
+    ...createFileTask(
+      filepath,
+      ctx.config.root,
+      projectName,
+      undefined,
+      undefined,
+      { typecheck: true },
+    ),
     start: ast.start,
     end: ast.end,
-    projectName,
-    meta: { typecheck: true },
-    file: null!,
+    mode: 'run',
   }
   file.file = file
   const definitions: LocalCallDefinition[] = []

From 7b3cee82385720916a58b6641ead7c58f6e184ad Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 1 Apr 2026 08:40:07 +0900
Subject: [PATCH 48/65] fix: sanitizeFilePath

---
 packages/utils/src/helpers.ts              |  5 +++++
 packages/vitest/src/node/reporters/blob.ts | 10 +++++++---
 packages/vitest/src/node/test-run.ts       |  7 +------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/packages/utils/src/helpers.ts b/packages/utils/src/helpers.ts
index 7d2d74cca233..22f1c0f7f59a 100644
--- a/packages/utils/src/helpers.ts
+++ b/packages/utils/src/helpers.ts
@@ -429,3 +429,8 @@ export function deepMerge<T extends object = object>(
 export function unique<T>(array: T[]): T[] {
   return Array.from(new Set(array))
 }
+
+export function sanitizeFilePath(s: string): string {
+  // eslint-disable-next-line no-control-regex
+  return s.replace(/[\x00-\x2C\x2E\x2F\x3A-\x40\x5B-\x60\x7B-\x7F]+/g, '-')
+}
diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index f352035124fe..f2af337295dc 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -7,6 +7,7 @@ import type { Reporter } from '../types/reporter'
 import type { TestModule } from './reported-tasks'
 import { existsSync } from 'node:fs'
 import { mkdir, readdir, readFile, stat, writeFile } from 'node:fs/promises'
+import { sanitizeFilePath } from '@vitest/utils/helpers'
 import { parse, stringify } from 'flatted'
 import { dirname, resolve } from 'pathe'
 import { getOutputFile } from '../../utils/config-helpers'
@@ -50,9 +51,12 @@ export class BlobReporter implements Reporter {
       = this.options.outputFile ?? getOutputFile(this.ctx.config, 'blob')
     if (!outputFile) {
       const shard = this.ctx.config.shard
-      const label = this.ctx.config.label
-      const suffix = [label, shard && `${shard.index}-${shard.count}`].filter(Boolean).join('-')
-      outputFile = suffix ? `.vitest-reports/blob-${suffix}.json` : '.vitest-reports/blob.json'
+      const filename = [
+        'blob',
+        this.ctx.config.label,
+        shard && `${shard.index}-${shard.count}`
+      ].filter(Boolean).join('-')
+      outputFile = `.vitest-reports/${sanitizeFilePath(filename)}.json`
     }
 
     const environmentModules: MergeReportEnvironmentModules = {}
diff --git a/packages/vitest/src/node/test-run.ts b/packages/vitest/src/node/test-run.ts
index b130052dcfaa..6493627585dd 100644
--- a/packages/vitest/src/node/test-run.ts
+++ b/packages/vitest/src/node/test-run.ts
@@ -17,7 +17,7 @@ import assert from 'node:assert'
 import { createHash } from 'node:crypto'
 import { existsSync, readFileSync } from 'node:fs'
 import { copyFile, mkdir, writeFile } from 'node:fs/promises'
-import { isPrimitive } from '@vitest/utils/helpers'
+import { isPrimitive, sanitizeFilePath } from '@vitest/utils/helpers'
 import { serializeValue } from '@vitest/utils/serialize'
 import { parseErrorStacktrace } from '@vitest/utils/source-map'
 import { extractSourcemapFromFile } from '@vitest/utils/source-map/node'
@@ -311,8 +311,3 @@ export class TestRun {
     }
   }
 }
-
-function sanitizeFilePath(s: string): string {
-  // eslint-disable-next-line no-control-regex
-  return s.replace(/[\x00-\x2C\x2E\x2F\x3A-\x40\x5B-\x60\x7B-\x7F]+/g, '-')
-}

From 39043c983b5e87773632379a919e53558d19946f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 1 Apr 2026 18:33:43 +0900
Subject: [PATCH 49/65] chore: lint

---
 packages/vitest/src/node/reporters/blob.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index f2af337295dc..9fb7c63265b0 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -54,7 +54,7 @@ export class BlobReporter implements Reporter {
       const filename = [
         'blob',
         this.ctx.config.label,
-        shard && `${shard.index}-${shard.count}`
+        shard && `${shard.index}-${shard.count}`,
       ].filter(Boolean).join('-')
       outputFile = `.vitest-reports/${sanitizeFilePath(filename)}.json`
     }

From 4d25b87118ee7780df9134a8deeabf29055ea4f0 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 1 Apr 2026 18:38:05 +0900
Subject: [PATCH 50/65] docs: mark label config experimental

Co-authored-by: Codex <noreply@openai.com>
---
 docs/config/label.md                     | 2 +-
 packages/vitest/src/node/types/config.ts | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/config/label.md b/docs/config/label.md
index 8e9954f19ffa..1f722b61bcdc 100644
--- a/docs/config/label.md
+++ b/docs/config/label.md
@@ -2,7 +2,7 @@
 title: label | Config
 ---
 
-# label <CRoot />
+# label <CRoot /> <Badge type="warning">experimental</Badge> <Version>4.1.3</Version>
 
 - **Type:** `string`
 - **CLI:** `--label=<label>`
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index 92a2ecbdd52a..0c66f91d246b 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -964,6 +964,7 @@ export interface InlineConfig {
 
   /**
    * Label to disambiguate the same test file when merging blob reports from different environments
+   * @experimental
    */
   label?: string
 }

From 5adf4db4b6c6db2238a3428309251a3e72cfdc34 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 8 Apr 2026 10:29:26 +0900
Subject: [PATCH 51/65] chore: rename meta.label -> __vitest_label__

---
 packages/runner/src/collect.ts                   |  9 ++++++++-
 packages/runner/src/utils/collect.ts             | 11 ++++++++---
 packages/ui/client/components/FileDetails.vue    |  2 +-
 packages/ui/client/composables/explorer/utils.ts |  4 ++--
 packages/vitest/src/node/reporters/base.ts       |  4 ++--
 packages/vitest/src/node/reporters/summary.ts    |  2 +-
 packages/vitest/src/node/state.ts                |  2 +-
 packages/vitest/src/node/test-specification.ts   |  2 +-
 packages/vitest/src/types/global.ts              |  2 +-
 packages/ws-client/src/state.ts                  |  4 +++-
 test/test-utils/index.ts                         |  4 +++-
 11 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/packages/runner/src/collect.ts b/packages/runner/src/collect.ts
index dc872eed8a52..0b80d479f7f6 100644
--- a/packages/runner/src/collect.ts
+++ b/packages/runner/src/collect.ts
@@ -47,7 +47,14 @@ export async function collectTests(
 
         const fileTags: string[] = typeof spec === 'string' ? [] : (spec.fileTags || [])
 
-        const file = createFileTask(filepath, config.root, config.name, runner.pool, runner.viteEnvironment, { label: config.label })
+        const file = createFileTask(
+          filepath,
+          config.root,
+          config.name,
+          runner.pool,
+          runner.viteEnvironment,
+          { __vitest_label__: config.label },
+        )
         file.tags = fileTags
         file.shuffle = config.sequence.shuffle
 
diff --git a/packages/runner/src/utils/collect.ts b/packages/runner/src/utils/collect.ts
index a7b9cea52e29..0a727488708f 100644
--- a/packages/runner/src/utils/collect.ts
+++ b/packages/runner/src/utils/collect.ts
@@ -193,13 +193,18 @@ export function calculateSuiteHash(parent: Suite): void {
   })
 }
 
+interface HashMeta {
+  typecheck?: boolean
+  __vitest_label__?: string
+}
+
 export function createFileTask(
   filepath: string,
   root: string,
   projectName: string | undefined,
   pool?: string,
   viteEnvironment?: string,
-  meta?: { typecheck?: boolean; label?: string },
+  meta?: HashMeta,
 ): File {
   const path = relative(root, filepath)
   const file: File = {
@@ -229,13 +234,13 @@ export function createFileTask(
 export function generateFileHash(
   file: string,
   projectName: string | undefined,
-  meta?: { typecheck?: boolean; label?: string },
+  meta?: HashMeta,
 ): string {
   const seed = [
     file,
     projectName || '',
     meta?.typecheck ? '__typecheck__' : '',
-    meta?.label || '',
+    meta?.__vitest_label__ || '',
   ].join('\0')
   return generateHash(seed)
 }
diff --git a/packages/ui/client/components/FileDetails.vue b/packages/ui/client/components/FileDetails.vue
index 40117e2fa514..7b016cd542bc 100644
--- a/packages/ui/client/components/FileDetails.vue
+++ b/packages/ui/client/components/FileDetails.vue
@@ -60,7 +60,7 @@ const isTypecheck = computed(() => {
   return !!current.value?.meta?.typecheck
 })
 
-const label = computed(() => current.value?.meta?.label)
+const label = computed(() => current.value?.meta?.__vitest_label__)
 
 function open() {
   const filePath = current.value?.filepath
diff --git a/packages/ui/client/composables/explorer/utils.ts b/packages/ui/client/composables/explorer/utils.ts
index 9ad93af19053..2ff576033c80 100644
--- a/packages/ui/client/composables/explorer/utils.ts
+++ b/packages/ui/client/composables/explorer/utils.ts
@@ -84,7 +84,7 @@ export function createOrUpdateFileNode(
 
   if (fileNode) {
     fileNode.typecheck = !!file.meta && 'typecheck' in file.meta
-    fileNode.label = file.meta?.label
+    fileNode.label = file.meta?.__vitest_label__
     fileNode.state = file.result?.state
     fileNode.mode = file.mode
     fileNode.duration = typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined
@@ -107,7 +107,7 @@ export function createOrUpdateFileNode(
       children: new Set(),
       tasks: [],
       typecheck: !!file.meta && 'typecheck' in file.meta,
-      label: file.meta?.label,
+      label: file.meta?.__vitest_label__,
       indent: 0,
       duration: typeof file.result?.duration === 'number' ? Math.round(file.result.duration) : undefined,
       slow: false,
diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index 3ce0258152a8..aec64e2ec106 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,7 +335,7 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
-    const label = entity.task.file.meta.label
+    const label = entity.task.file.meta.__vitest_label__
     if (label) {
       title += ` ${c.bgCyan(c.bold(` ${label} `))}`
     }
@@ -941,7 +941,7 @@ export abstract class BaseReporter implements Reporter {
           name += c.dim(` [ ${this.relative(filepath)} ]`)
         }
 
-        const label = task.file?.meta?.label
+        const label = task.file?.meta?.__vitest_label__
         this.ctx.logger.error(
           `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${label ? `${c.bgCyan(c.bold(` ${label} `))} ` : ''}${name}`,
         )
diff --git a/packages/vitest/src/node/reporters/summary.ts b/packages/vitest/src/node/reporters/summary.ts
index 01c005c0d0b8..3d144edd5848 100644
--- a/packages/vitest/src/node/reporters/summary.ts
+++ b/packages/vitest/src/node/reporters/summary.ts
@@ -289,7 +289,7 @@ export class SummaryReporter implements Reporter {
 
     for (const testFile of Array.from(this.runningModules.values()).sort(sortRunningModules)) {
       const typecheck = testFile.meta.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
-      const label = testFile.meta.label ? `${c.bgCyan(c.bold(` ${testFile.meta.label} `))} ` : ''
+      const label = testFile.meta.__vitest_label__ ? `${c.bgCyan(c.bold(` ${testFile.meta.__vitest_label__} `))} ` : ''
       summary.push(
         c.bold(c.yellow(` ${F_POINTER} `))
         + formatProjectName({ name: testFile.projectName, color: testFile.projectColor })
diff --git a/packages/vitest/src/node/state.ts b/packages/vitest/src/node/state.ts
index 0379976fa1dd..76ea5b71ce4d 100644
--- a/packages/vitest/src/node/state.ts
+++ b/packages/vitest/src/node/state.ts
@@ -148,7 +148,7 @@ export class StateManager {
       const currentFile = existing.find(
         i => i.projectName === file.projectName
           && i.meta.typecheck === file.meta.typecheck
-          && i.meta.label === file.meta.label,
+          && i.meta.__vitest_label__ === file.meta.__vitest_label__,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index 04312bf9ecb6..d47543f54797 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -62,7 +62,7 @@ export class TestSpecification {
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      meta ?? { typecheck: pool === 'typescript', label: project.config.label },
+      meta ?? { typecheck: pool === 'typescript', __vitest_label__: project.config.label },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/packages/vitest/src/types/global.ts b/packages/vitest/src/types/global.ts
index 2397bdf2f6be..30140cf9a1bd 100644
--- a/packages/vitest/src/types/global.ts
+++ b/packages/vitest/src/types/global.ts
@@ -110,7 +110,7 @@ declare module '@vitest/runner' {
   interface TaskMeta {
     typecheck?: boolean
     benchmark?: boolean
-    label?: string
+    __vitest_label__?: string
   }
 
   interface File {
diff --git a/packages/ws-client/src/state.ts b/packages/ws-client/src/state.ts
index 981a25d7a823..b5a1d1762418 100644
--- a/packages/ws-client/src/state.ts
+++ b/packages/ws-client/src/state.ts
@@ -48,7 +48,9 @@ export class StateManager {
     files.forEach((file) => {
       const existing = this.filesMap.get(file.filepath) || []
       const currentFile = existing.find(
-        i => i.projectName === file.projectName && i.meta.typecheck === file.meta.typecheck && i.meta.label === file.meta.label,
+        i => i.projectName === file.projectName
+          && i.meta.typecheck === file.meta.typecheck
+          && i.meta.__vitest_label__ === file.meta.__vitest_label__,
       )
       // keep logs for the previous file because it should always be initiated before the collections phase
       // which means that all logs are collected during the collection and not inside tests
diff --git a/test/test-utils/index.ts b/test/test-utils/index.ts
index 2127ab6f450b..a6aaf8855f1e 100644
--- a/test/test-utils/index.ts
+++ b/test/test-utils/index.ts
@@ -620,7 +620,9 @@ export function buildErrorTree(testModules: TestModule[], options?: BuildErrorTr
       }
       return moduleChildren
     },
-    options?.fileLabel ? module => `${module.relativeModuleId} (${module.meta().label})` : undefined,
+    options?.fileLabel
+      ? module => `${module.relativeModuleId} (${module.meta().__vitest_label__})`
+      : undefined,
   )
 }
 

From f0f303ea3b85030362d03c35405ac24cfc2c469f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 8 Apr 2026 11:20:13 +0900
Subject: [PATCH 52/65] fix: align pre-parse file identity with specification
 meta

Co-authored-by: Codex <noreply@openai.com>
---
 packages/vitest/src/node/ast-collect.ts       | 23 +++++++++++++++----
 packages/vitest/src/node/core.ts              | 18 +++++++++++----
 .../vitest/src/node/test-specification.ts     | 11 ++++++++-
 3 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/packages/vitest/src/node/ast-collect.ts b/packages/vitest/src/node/ast-collect.ts
index 32f9bc72234b..ac438b1b2fe3 100644
--- a/packages/vitest/src/node/ast-collect.ts
+++ b/packages/vitest/src/node/ast-collect.ts
@@ -1,4 +1,4 @@
-import type { File, Suite, Task, Test } from '@vitest/runner'
+import type { File, Suite, Task, TaskMeta, Test } from '@vitest/runner'
 import type { SerializedConfig } from '../runtime/config'
 import type { TestError } from '../types/general'
 import type { TestProject } from './project'
@@ -7,7 +7,7 @@ import { originalPositionFor, TraceMap } from '@jridgewell/trace-mapping'
 import {
   calculateSuiteHash,
   createTaskName,
-  generateHash,
+  generateFileHash,
   validateTags,
 } from '@vitest/runner/utils'
 import { unique } from '@vitest/utils/helpers'
@@ -281,12 +281,16 @@ function astParseFile(filepath: string, code: string) {
   }
 }
 
-export function createFailedFileTask(project: TestProject, filepath: string, error: Error): File {
+export function createFailedFileTask(project: TestProject, filepath: string, error: Error, meta?: TaskMeta): File {
   const testFilepath = relative(project.config.root, filepath)
   const file: ParsedFile = {
     filepath,
     type: 'suite',
-    id: /* @__PURE__ */ generateHash(`${testFilepath}${project.config.name || ''}`),
+    id: /* @__PURE__ */ generateFileHash(
+      testFilepath,
+      project.config.name,
+      meta ?? { __vitest_label__: project.config.label },
+    ),
     name: testFilepath,
     fullName: testFilepath,
     mode: 'run',
@@ -335,12 +339,18 @@ function createFileTask(
   config: SerializedConfig,
   filepath: string,
   fileTags: string[] | undefined,
+  meta?: TaskMeta,
 ) {
   const { definitions, ast } = astParseFile(testFilepath, code)
+  // TODO: use createFileTask from packages/runner
   const file: ParsedFile = {
     filepath,
     type: 'suite',
-    id: /* @__PURE__ */ generateHash(`${testFilepath}${config.name || ''}`),
+    id: /* @__PURE__ */ generateFileHash(
+      testFilepath,
+      config.name,
+      meta ?? { __vitest_label__: config.label },
+    ),
     name: testFilepath,
     fullName: testFilepath,
     mode: 'run',
@@ -488,6 +498,7 @@ function createFileTask(
 export async function astCollectTests(
   project: TestProject,
   filepath: string,
+  meta?: TaskMeta,
 ): Promise<File> {
   const request = await transformSSR(project, filepath)
   const testFilepath = relative(project.config.root, filepath)
@@ -497,6 +508,7 @@ export async function astCollectTests(
       project,
       filepath,
       new Error(`Failed to parse ${testFilepath}. Vite didn't return anything.`),
+      meta,
     )
   }
   return createFileTask(
@@ -506,6 +518,7 @@ export async function astCollectTests(
     project.serializedConfig,
     filepath,
     request.fileTags,
+    meta,
   )
 }
 
diff --git a/packages/vitest/src/node/core.ts b/packages/vitest/src/node/core.ts
index 1a43ef498856..eff2dbbae538 100644
--- a/packages/vitest/src/node/core.ts
+++ b/packages/vitest/src/node/core.ts
@@ -1044,8 +1044,13 @@ export class Vitest {
     // Phase 1: parse all files in parallel (without mode interpretation)
     const results = await Promise.all(specifications.map(specification =>
       limit(async () => {
-        const file = await astCollectTests(specification.project, specification.moduleId).catch((error) => {
-          return createFailedFileTask(specification.project, specification.moduleId, error)
+        const file = await astCollectTests(specification.project, specification.moduleId, specification.meta).catch((error) => {
+          return createFailedFileTask(
+            specification.project,
+            specification.moduleId,
+            error,
+            specification.meta,
+          )
         })
         return { file, specification }
       }),
@@ -1078,8 +1083,13 @@ export class Vitest {
     if (this.mode !== 'test') {
       throw new Error(`The \`experimental_parseSpecification\` does not support "${this.mode}" mode.`)
     }
-    const file = await astCollectTests(specification.project, specification.moduleId).catch((error) => {
-      return createFailedFileTask(specification.project, specification.moduleId, error)
+    const file = await astCollectTests(specification.project, specification.moduleId, specification.meta).catch((error) => {
+      return createFailedFileTask(
+        specification.project,
+        specification.moduleId,
+        error,
+        specification.meta,
+      )
     })
     const config = specification.project.config
     const hasOnly = someTasksAreOnly(file)
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index d47543f54797..f3487d21d3df 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -30,6 +30,10 @@ export class TestSpecification {
    * The current test pool. It's possible to have multiple pools in a single test project with `typecheck.enabled`.
    */
   public readonly pool: Pool
+  /**
+   * Internal metadata used to derive the file task identity.
+   */
+  public readonly meta: TaskMeta
   /**
    * Line numbers of the test locations to run.
    */
@@ -59,14 +63,19 @@ export class TestSpecification {
     meta?: TaskMeta,
   ) {
     const projectName = project.config.name
+    const resolvedMeta = meta ?? {
+      typecheck: pool === 'typescript',
+      __vitest_label__: project.config.label,
+    }
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      meta ?? { typecheck: pool === 'typescript', __vitest_label__: project.config.label },
+      resolvedMeta,
     )
     this.project = project
     this.moduleId = moduleId
     this.pool = pool
+    this.meta = resolvedMeta
     if (Array.isArray(testLinesOrOptions)) {
       this.testLines = testLinesOrOptions
     }

From fb3ac414f91b7b3e80931462f89a47ffa33a5ae8 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 8 Apr 2026 11:38:44 +0900
Subject: [PATCH 53/65] refactor: de-slop

---
 packages/vitest/src/node/ast-collect.ts       | 65 +++++++------------
 packages/vitest/src/node/core.ts              | 18 ++---
 packages/vitest/src/node/project.ts           |  4 +-
 .../vitest/src/node/test-specification.ts     | 14 +---
 4 files changed, 34 insertions(+), 67 deletions(-)

diff --git a/packages/vitest/src/node/ast-collect.ts b/packages/vitest/src/node/ast-collect.ts
index ac438b1b2fe3..ffb4d91e240c 100644
--- a/packages/vitest/src/node/ast-collect.ts
+++ b/packages/vitest/src/node/ast-collect.ts
@@ -1,13 +1,12 @@
-import type { File, Suite, Task, TaskMeta, Test } from '@vitest/runner'
-import type { SerializedConfig } from '../runtime/config'
+import type { File, Suite, Task, Test } from '@vitest/runner'
 import type { TestError } from '../types/general'
 import type { TestProject } from './project'
 import { promises as fs } from 'node:fs'
 import { originalPositionFor, TraceMap } from '@jridgewell/trace-mapping'
 import {
   calculateSuiteHash,
+  createFileTask as createFileTaskOriginal,
   createTaskName,
-  generateFileHash,
   validateTags,
 } from '@vitest/runner/utils'
 import { unique } from '@vitest/utils/helpers'
@@ -281,26 +280,21 @@ function astParseFile(filepath: string, code: string) {
   }
 }
 
-export function createFailedFileTask(project: TestProject, filepath: string, error: Error, meta?: TaskMeta): File {
-  const testFilepath = relative(project.config.root, filepath)
-  const file: ParsedFile = {
+export function createFailedFileTask(project: TestProject, filepath: string, error: Error): File {
+  const config = project.serializedConfig
+  const baseFile = createFileTaskOriginal(
     filepath,
-    type: 'suite',
-    id: /* @__PURE__ */ generateFileHash(
-      testFilepath,
-      project.config.name,
-      meta ?? { __vitest_label__: project.config.label },
-    ),
-    name: testFilepath,
-    fullName: testFilepath,
+    config.root,
+    config.name,
+    config.pool,
+    undefined,
+    { typecheck: false, __vitest_label__: config.label },
+  )
+  const file: ParsedFile = {
+    ...baseFile,
     mode: 'run',
-    tasks: [],
     start: 0,
     end: 0,
-    projectName: project.name,
-    meta: {},
-    pool: project.browser ? 'browser' : project.config.pool,
-    file: null!,
     result: {
       state: 'fail',
       errors: serializeError(project, error),
@@ -333,34 +327,28 @@ function serializeError(ctx: TestProject, error: any): TestError[] {
 }
 
 function createFileTask(
+  project: TestProject,
   testFilepath: string,
   code: string,
   requestMap: any,
-  config: SerializedConfig,
   filepath: string,
   fileTags: string[] | undefined,
-  meta?: TaskMeta,
 ) {
   const { definitions, ast } = astParseFile(testFilepath, code)
-  // TODO: use createFileTask from packages/runner
-  const file: ParsedFile = {
+  const config = project.serializedConfig
+  const baseFile = createFileTaskOriginal(
     filepath,
-    type: 'suite',
-    id: /* @__PURE__ */ generateFileHash(
-      testFilepath,
-      config.name,
-      meta ?? { __vitest_label__: config.label },
-    ),
-    name: testFilepath,
-    fullName: testFilepath,
+    config.root,
+    config.name,
+    config.pool,
+    undefined,
+    { typecheck: false, __vitest_label__: config.label },
+  )
+  const file: ParsedFile = {
+    ...baseFile,
     mode: 'run',
-    tasks: [],
     start: ast.start,
     end: ast.end,
-    projectName: config.name,
-    meta: {},
-    pool: 'browser',
-    file: null!,
     tags: fileTags || [],
   }
   file.file = file
@@ -498,7 +486,6 @@ function createFileTask(
 export async function astCollectTests(
   project: TestProject,
   filepath: string,
-  meta?: TaskMeta,
 ): Promise<File> {
   const request = await transformSSR(project, filepath)
   const testFilepath = relative(project.config.root, filepath)
@@ -508,17 +495,15 @@ export async function astCollectTests(
       project,
       filepath,
       new Error(`Failed to parse ${testFilepath}. Vite didn't return anything.`),
-      meta,
     )
   }
   return createFileTask(
+    project,
     testFilepath,
     request.code,
     request.map,
-    project.serializedConfig,
     filepath,
     request.fileTags,
-    meta,
   )
 }
 
diff --git a/packages/vitest/src/node/core.ts b/packages/vitest/src/node/core.ts
index eff2dbbae538..1a43ef498856 100644
--- a/packages/vitest/src/node/core.ts
+++ b/packages/vitest/src/node/core.ts
@@ -1044,13 +1044,8 @@ export class Vitest {
     // Phase 1: parse all files in parallel (without mode interpretation)
     const results = await Promise.all(specifications.map(specification =>
       limit(async () => {
-        const file = await astCollectTests(specification.project, specification.moduleId, specification.meta).catch((error) => {
-          return createFailedFileTask(
-            specification.project,
-            specification.moduleId,
-            error,
-            specification.meta,
-          )
+        const file = await astCollectTests(specification.project, specification.moduleId).catch((error) => {
+          return createFailedFileTask(specification.project, specification.moduleId, error)
         })
         return { file, specification }
       }),
@@ -1083,13 +1078,8 @@ export class Vitest {
     if (this.mode !== 'test') {
       throw new Error(`The \`experimental_parseSpecification\` does not support "${this.mode}" mode.`)
     }
-    const file = await astCollectTests(specification.project, specification.moduleId, specification.meta).catch((error) => {
-      return createFailedFileTask(
-        specification.project,
-        specification.moduleId,
-        error,
-        specification.meta,
-      )
+    const file = await astCollectTests(specification.project, specification.moduleId).catch((error) => {
+      return createFailedFileTask(specification.project, specification.moduleId, error)
     })
     const config = specification.project.config
     const hasOnly = someTasksAreOnly(file)
diff --git a/packages/vitest/src/node/project.ts b/packages/vitest/src/node/project.ts
index d44970672b4e..e1b984cf7d89 100644
--- a/packages/vitest/src/node/project.ts
+++ b/packages/vitest/src/node/project.ts
@@ -154,14 +154,14 @@ export class TestProject {
     /** @internal */
     pool?: string,
     /** @internal */
-    meta?: TaskMeta,
+    metaOverride?: TaskMeta,
   ): TestSpecification {
     return new TestSpecification(
       this,
       moduleId,
       pool || getFilePoolName(this),
       locationsOrOptions,
-      meta,
+      metaOverride,
     )
   }
 
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index f3487d21d3df..d0bdc43c0090 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -30,10 +30,6 @@ export class TestSpecification {
    * The current test pool. It's possible to have multiple pools in a single test project with `typecheck.enabled`.
    */
   public readonly pool: Pool
-  /**
-   * Internal metadata used to derive the file task identity.
-   */
-  public readonly meta: TaskMeta
   /**
    * Line numbers of the test locations to run.
    */
@@ -60,22 +56,18 @@ export class TestSpecification {
     moduleId: string,
     pool: Pool,
     testLinesOrOptions?: number[] | TestSpecificationOptions | undefined,
-    meta?: TaskMeta,
+    // merge-reports uses the original `file.meta` from the test run
+    metaOverride?: TaskMeta,
   ) {
     const projectName = project.config.name
-    const resolvedMeta = meta ?? {
-      typecheck: pool === 'typescript',
-      __vitest_label__: project.config.label,
-    }
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      resolvedMeta,
+      metaOverride ?? { typecheck: pool === 'typescript', __vitest_label__: project.config.label },
     )
     this.project = project
     this.moduleId = moduleId
     this.pool = pool
-    this.meta = resolvedMeta
     if (Array.isArray(testLinesOrOptions)) {
       this.testLines = testLinesOrOptions
     }

From dd60c7bb8e7f57973585c92c1b042988833bbe79 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 8 Apr 2026 11:46:25 +0900
Subject: [PATCH 54/65] fix: handle meta.typecheck in ast-collect

---
 packages/vitest/src/node/ast-collect.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/vitest/src/node/ast-collect.ts b/packages/vitest/src/node/ast-collect.ts
index ffb4d91e240c..e3877882d767 100644
--- a/packages/vitest/src/node/ast-collect.ts
+++ b/packages/vitest/src/node/ast-collect.ts
@@ -288,7 +288,7 @@ export function createFailedFileTask(project: TestProject, filepath: string, err
     config.name,
     config.pool,
     undefined,
-    { typecheck: false, __vitest_label__: config.label },
+    { typecheck: config.pool === 'typescript', __vitest_label__: config.label },
   )
   const file: ParsedFile = {
     ...baseFile,
@@ -342,7 +342,7 @@ function createFileTask(
     config.name,
     config.pool,
     undefined,
-    { typecheck: false, __vitest_label__: config.label },
+    { typecheck: config.pool === 'typescript', __vitest_label__: config.label },
   )
   const file: ParsedFile = {
     ...baseFile,

From 3efd0845c00922de6268b96929968d89071a223c Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Wed, 8 Apr 2026 11:48:15 +0900
Subject: [PATCH 55/65] test: update static-collect task id

---
 test/cli/test/static-collect.test.ts | 192 +++++++++++++--------------
 1 file changed, 96 insertions(+), 96 deletions(-)

diff --git a/test/cli/test/static-collect.test.ts b/test/cli/test/static-collect.test.ts
index 423172c0a26c..07f931cc42ef 100644
--- a/test/cli/test/static-collect.test.ts
+++ b/test/cli/test/static-collect.test.ts
@@ -24,7 +24,7 @@ test('correctly collects a simple test', async () => {
         "adds numbers": {
           "errors": [],
           "fullName": "math operations > adds numbers",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -32,7 +32,7 @@ test('correctly collects a simple test', async () => {
         "subtracts numbers": {
           "errors": [],
           "fullName": "math operations > subtracts numbers",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "9:6",
           "mode": "skip",
           "state": "skipped",
@@ -57,7 +57,7 @@ test('collects tests starting with "test"', async () => {
         "works with testAnother": {
           "errors": [],
           "fullName": "custom test functions > works with testAnother",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -65,7 +65,7 @@ test('collects tests starting with "test"', async () => {
         "works with testSomething": {
           "errors": [],
           "fullName": "custom test functions > works with testSomething",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -90,7 +90,7 @@ test('collects tests ending with "Test"', async () => {
         "works with integrationTest": {
           "errors": [],
           "fullName": "custom test functions > works with integrationTest",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -98,7 +98,7 @@ test('collects tests ending with "Test"', async () => {
         "works with unitTest": {
           "errors": [],
           "fullName": "custom test functions > works with unitTest",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -124,7 +124,7 @@ test('collects tests with only modifier', async () => {
         "barTest with only": {
           "errors": [],
           "fullName": "only tests > barTest with only",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "run",
           "state": "pending",
@@ -132,7 +132,7 @@ test('collects tests with only modifier', async () => {
         "regular test with only": {
           "errors": [],
           "fullName": "only tests > regular test with only",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -140,7 +140,7 @@ test('collects tests with only modifier', async () => {
         "testFoo with only": {
           "errors": [],
           "fullName": "only tests > testFoo with only",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -166,7 +166,7 @@ test('collects tests with skip modifier', async () => {
         "barTest with skip": {
           "errors": [],
           "fullName": "skip tests > barTest with skip",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "skip",
           "state": "skipped",
@@ -174,7 +174,7 @@ test('collects tests with skip modifier', async () => {
         "regular test with skip": {
           "errors": [],
           "fullName": "skip tests > regular test with skip",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -182,7 +182,7 @@ test('collects tests with skip modifier', async () => {
         "testFoo with skip": {
           "errors": [],
           "fullName": "skip tests > testFoo with skip",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -208,7 +208,7 @@ test('collects tests with todo modifier', async () => {
         "barTest with todo": {
           "errors": [],
           "fullName": "todo tests > barTest with todo",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "todo",
           "state": "skipped",
@@ -216,7 +216,7 @@ test('collects tests with todo modifier', async () => {
         "regular test with todo": {
           "errors": [],
           "fullName": "todo tests > regular test with todo",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "todo",
           "state": "skipped",
@@ -224,7 +224,7 @@ test('collects tests with todo modifier', async () => {
         "testFoo with todo": {
           "errors": [],
           "fullName": "todo tests > testFoo with todo",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "todo",
           "state": "skipped",
@@ -258,7 +258,7 @@ test('collects nested suites with custom test functions', async () => {
             "integration test": {
               "errors": [],
               "fullName": "outer suite > inner suite > deeply nested > integration test",
-              "id": "-1732721377_0_1_1_0",
+              "id": "1709388417_0_1_1_0",
               "location": "11:10",
               "mode": "run",
               "state": "pending",
@@ -267,7 +267,7 @@ test('collects nested suites with custom test functions', async () => {
           "unit test": {
             "errors": [],
             "fullName": "outer suite > inner suite > unit test",
-            "id": "-1732721377_0_1_0",
+            "id": "1709388417_0_1_0",
             "location": "8:8",
             "mode": "run",
             "state": "pending",
@@ -276,7 +276,7 @@ test('collects nested suites with custom test functions', async () => {
         "regular test": {
           "errors": [],
           "fullName": "outer suite > regular test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -311,7 +311,7 @@ test('ignores test.scoped and test.override', async () => {
         "only extended test": {
           "errors": [],
           "fullName": "extended tests > only extended test",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "16:6",
           "mode": "run",
           "state": "pending",
@@ -319,7 +319,7 @@ test('ignores test.scoped and test.override', async () => {
         "skips extended test": {
           "errors": [],
           "fullName": "extended tests > skips extended test",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "15:6",
           "mode": "skip",
           "state": "skipped",
@@ -327,7 +327,7 @@ test('ignores test.scoped and test.override', async () => {
         "uses extended test": {
           "errors": [],
           "fullName": "extended tests > uses extended test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "14:6",
           "mode": "skip",
           "state": "skipped",
@@ -359,7 +359,7 @@ test('collects tests from test.extend', async () => {
         "only extended test": {
           "errors": [],
           "fullName": "extended tests > only extended test",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "13:6",
           "mode": "run",
           "state": "pending",
@@ -367,7 +367,7 @@ test('collects tests from test.extend', async () => {
         "skips extended test": {
           "errors": [],
           "fullName": "extended tests > skips extended test",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "12:6",
           "mode": "skip",
           "state": "skipped",
@@ -375,7 +375,7 @@ test('collects tests from test.extend', async () => {
         "uses extended test": {
           "errors": [],
           "fullName": "extended tests > uses extended test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "11:6",
           "mode": "skip",
           "state": "skipped",
@@ -401,7 +401,7 @@ test('collects tests imported from another file', async () => {
         "only imported test": {
           "errors": [],
           "fullName": "imported test function > only imported test",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "run",
           "state": "pending",
@@ -409,7 +409,7 @@ test('collects tests imported from another file', async () => {
         "skips imported test": {
           "errors": [],
           "fullName": "imported test function > skips imported test",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -417,7 +417,7 @@ test('collects tests imported from another file', async () => {
         "uses imported test": {
           "errors": [],
           "fullName": "imported test function > uses imported test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -444,7 +444,7 @@ test('collects mixed test function names', async () => {
         "classic it syntax": {
           "errors": [],
           "fullName": "mixed tests > classic it syntax",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -452,7 +452,7 @@ test('collects mixed test function names', async () => {
         "ends with Test": {
           "errors": [],
           "fullName": "mixed tests > ends with Test",
-          "id": "-1732721377_0_3",
+          "id": "1709388417_0_3",
           "location": "8:6",
           "mode": "run",
           "state": "pending",
@@ -460,7 +460,7 @@ test('collects mixed test function names', async () => {
         "standard test": {
           "errors": [],
           "fullName": "mixed tests > standard test",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -468,7 +468,7 @@ test('collects mixed test function names', async () => {
         "starts with test": {
           "errors": [],
           "fullName": "mixed tests > starts with test",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "run",
           "state": "pending",
@@ -495,7 +495,7 @@ test('collects tests with all modifiers on custom functions', async () => {
         "normal custom test": {
           "errors": [],
           "fullName": "custom test with modifiers > normal custom test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -503,7 +503,7 @@ test('collects tests with all modifiers on custom functions', async () => {
         "only custom test": {
           "errors": [],
           "fullName": "custom test with modifiers > only custom test",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "run",
           "state": "pending",
@@ -511,7 +511,7 @@ test('collects tests with all modifiers on custom functions', async () => {
         "skipped custom test": {
           "errors": [],
           "fullName": "custom test with modifiers > skipped custom test",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -519,7 +519,7 @@ test('collects tests with all modifiers on custom functions', async () => {
         "todo custom test": {
           "errors": [],
           "fullName": "custom test with modifiers > todo custom test",
-          "id": "-1732721377_0_3",
+          "id": "1709388417_0_3",
           "location": "8:6",
           "mode": "todo",
           "state": "skipped",
@@ -545,7 +545,7 @@ test('collects tests in skipped suites', async () => {
         "barTest in skipped suite": {
           "errors": [],
           "fullName": "skipped suite > barTest in skipped suite",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "skip",
           "state": "skipped",
@@ -553,7 +553,7 @@ test('collects tests in skipped suites', async () => {
         "regular test in skipped suite": {
           "errors": [],
           "fullName": "skipped suite > regular test in skipped suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -561,7 +561,7 @@ test('collects tests in skipped suites', async () => {
         "testFoo in skipped suite": {
           "errors": [],
           "fullName": "skipped suite > testFoo in skipped suite",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -587,7 +587,7 @@ test('collects tests in only suites', async () => {
         "barTest in only suite": {
           "errors": [],
           "fullName": "only suite > barTest in only suite",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "run",
           "state": "pending",
@@ -595,7 +595,7 @@ test('collects tests in only suites', async () => {
         "regular test in only suite": {
           "errors": [],
           "fullName": "only suite > regular test in only suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -603,7 +603,7 @@ test('collects tests in only suites', async () => {
         "testFoo in only suite": {
           "errors": [],
           "fullName": "only suite > testFoo in only suite",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -631,7 +631,7 @@ test('collects tests with each modifier', async () => {
           "each": true,
           "errors": [],
           "fullName": "each tests > barTest with each %i",
-          "id": "-1732721377_0_2-dynamic",
+          "id": "1709388417_0_2-dynamic",
           "location": "7:28",
           "mode": "run",
           "state": "pending",
@@ -641,7 +641,7 @@ test('collects tests with each modifier', async () => {
           "each": true,
           "errors": [],
           "fullName": "each tests > test with each %i",
-          "id": "-1732721377_0_0-dynamic",
+          "id": "1709388417_0_0-dynamic",
           "location": "5:25",
           "mode": "run",
           "state": "pending",
@@ -651,7 +651,7 @@ test('collects tests with each modifier', async () => {
           "each": true,
           "errors": [],
           "fullName": "each tests > testFoo with each %i",
-          "id": "-1732721377_0_1-dynamic",
+          "id": "1709388417_0_1-dynamic",
           "location": "6:28",
           "mode": "run",
           "state": "pending",
@@ -691,7 +691,7 @@ test('collects complex nested structure with custom functions', async () => {
           "first integration": {
             "errors": [],
             "fullName": "root suite > integration tests > first integration",
-            "id": "-1732721377_0_2_0",
+            "id": "1709388417_0_2_0",
             "location": "17:8",
             "mode": "run",
             "state": "pending",
@@ -699,7 +699,7 @@ test('collects complex nested structure with custom functions', async () => {
           "focused integration": {
             "errors": [],
             "fullName": "root suite > integration tests > focused integration",
-            "id": "-1732721377_0_2_1",
+            "id": "1709388417_0_2_1",
             "location": "18:8",
             "mode": "run",
             "state": "pending",
@@ -707,7 +707,7 @@ test('collects complex nested structure with custom functions', async () => {
           "planned integration": {
             "errors": [],
             "fullName": "root suite > integration tests > planned integration",
-            "id": "-1732721377_0_2_2",
+            "id": "1709388417_0_2_2",
             "location": "19:8",
             "mode": "run",
             "state": "pending",
@@ -716,7 +716,7 @@ test('collects complex nested structure with custom functions', async () => {
         "root test": {
           "errors": [],
           "fullName": "root suite > root test",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -725,7 +725,7 @@ test('collects complex nested structure with custom functions', async () => {
           "first unit test": {
             "errors": [],
             "fullName": "root suite > unit tests > first unit test",
-            "id": "-1732721377_0_1_0",
+            "id": "1709388417_0_1_0",
             "location": "8:8",
             "mode": "skip",
             "state": "skipped",
@@ -734,7 +734,7 @@ test('collects complex nested structure with custom functions', async () => {
             "test in skipped suite": {
               "errors": [],
               "fullName": "root suite > unit tests > skipped nested > test in skipped suite",
-              "id": "-1732721377_0_1_2_0",
+              "id": "1709388417_0_1_2_0",
               "location": "12:10",
               "mode": "skip",
               "state": "skipped",
@@ -743,7 +743,7 @@ test('collects complex nested structure with custom functions', async () => {
           "skipped unit test": {
             "errors": [],
             "fullName": "root suite > unit tests > skipped unit test",
-            "id": "-1732721377_0_1_1",
+            "id": "1709388417_0_1_1",
             "location": "9:8",
             "mode": "skip",
             "state": "skipped",
@@ -774,7 +774,7 @@ test('collects tests when test functions are globals', async () => {
         "it as global": {
           "errors": [],
           "fullName": "global test functions > it as global",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "4:6",
           "mode": "skip",
           "state": "skipped",
@@ -782,7 +782,7 @@ test('collects tests when test functions are globals', async () => {
         "myTest as global": {
           "errors": [],
           "fullName": "global test functions > myTest as global",
-          "id": "-1732721377_0_3",
+          "id": "1709388417_0_3",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -791,7 +791,7 @@ test('collects tests when test functions are globals', async () => {
           "skipped global test": {
             "errors": [],
             "fullName": "global test functions > nested > skipped global test",
-            "id": "-1732721377_0_4_0",
+            "id": "1709388417_0_4_0",
             "location": "9:8",
             "mode": "skip",
             "state": "skipped",
@@ -799,7 +799,7 @@ test('collects tests when test functions are globals', async () => {
           "testUnit.only as global": {
             "errors": [],
             "fullName": "global test functions > nested > testUnit.only as global",
-            "id": "-1732721377_0_4_1",
+            "id": "1709388417_0_4_1",
             "location": "10:8",
             "mode": "run",
             "state": "pending",
@@ -808,7 +808,7 @@ test('collects tests when test functions are globals', async () => {
         "test as global": {
           "errors": [],
           "fullName": "global test functions > test as global",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "3:6",
           "mode": "skip",
           "state": "skipped",
@@ -816,7 +816,7 @@ test('collects tests when test functions are globals', async () => {
         "testSomething as global": {
           "errors": [],
           "fullName": "global test functions > testSomething as global",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -839,7 +839,7 @@ test('remove .name from the function identifiers', async () => {
       "Service": {
         "errors": [],
         "fullName": "Service",
-        "id": "-1732721377_0",
+        "id": "1709388417_0",
         "location": "4:4",
         "mode": "run",
         "state": "pending",
@@ -863,7 +863,7 @@ test('collects tests with tags as a string', async () => {
         "test with single tag": {
           "errors": [],
           "fullName": "tagged tests > test with single tag",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -874,7 +874,7 @@ test('collects tests with tags as a string', async () => {
         "test without tags": {
           "errors": [],
           "fullName": "tagged tests > test without tags",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -899,7 +899,7 @@ test('collects tests with tags as an array', async () => {
         "test with empty tags": {
           "errors": [],
           "fullName": "tagged tests > test with empty tags",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -907,7 +907,7 @@ test('collects tests with tags as an array', async () => {
         "test with multiple tags": {
           "errors": [],
           "fullName": "tagged tests > test with multiple tags",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -935,7 +935,7 @@ test('collects suites with tags', async () => {
         "test in tagged suite": {
           "errors": [],
           "fullName": "tagged suite > test in tagged suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -968,7 +968,7 @@ test('inherits tags from parent suites', async () => {
           "test inherits both tags": {
             "errors": [],
             "fullName": "outer suite > inner suite > test inherits both tags",
-            "id": "-1732721377_0_1_0",
+            "id": "1709388417_0_1_0",
             "location": "8:8",
             "mode": "run",
             "state": "pending",
@@ -980,7 +980,7 @@ test('inherits tags from parent suites', async () => {
           "test with own tag": {
             "errors": [],
             "fullName": "outer suite > inner suite > test with own tag",
-            "id": "-1732721377_0_1_1",
+            "id": "1709388417_0_1_1",
             "location": "9:8",
             "mode": "run",
             "state": "pending",
@@ -994,7 +994,7 @@ test('inherits tags from parent suites', async () => {
         "test inherits parent tag": {
           "errors": [],
           "fullName": "outer suite > test inherits parent tag",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1022,7 +1022,7 @@ test('collects tags with other options', async () => {
         "skipped test with tags": {
           "errors": [],
           "fullName": "tests with options > skipped test with tags",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -1033,7 +1033,7 @@ test('collects tags with other options', async () => {
         "test with tags and timeout": {
           "errors": [],
           "fullName": "tests with options > test with tags and timeout",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1069,7 +1069,7 @@ test('sequential cancels inherited concurrent', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "concurrent suite > inherits concurrent",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1079,7 +1079,7 @@ test('sequential cancels inherited concurrent', async () => {
             "concurrent": true,
             "errors": [],
             "fullName": "concurrent suite > regular nested > still concurrent",
-            "id": "-1732721377_0_2_0",
+            "id": "1709388417_0_2_0",
             "location": "12:8",
             "mode": "run",
             "state": "pending",
@@ -1089,7 +1089,7 @@ test('sequential cancels inherited concurrent', async () => {
           "not concurrent": {
             "errors": [],
             "fullName": "concurrent suite > sequential nested > not concurrent",
-            "id": "-1732721377_0_1_0",
+            "id": "1709388417_0_1_0",
             "location": "8:8",
             "mode": "run",
             "state": "pending",
@@ -1116,7 +1116,7 @@ test('collects tests with sequential modifier', async () => {
         "test in sequential suite": {
           "errors": [],
           "fullName": "sequential suite > test in sequential suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1125,7 +1125,7 @@ test('collects tests with sequential modifier', async () => {
       "sequential test": {
         "errors": [],
         "fullName": "sequential test",
-        "id": "-1732721377_1",
+        "id": "1709388417_1",
         "location": "8:4",
         "mode": "run",
         "state": "pending",
@@ -1151,7 +1151,7 @@ test('collects tests with concurrent modifier in different order', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "concurrent suite > test in concurrent suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -1160,7 +1160,7 @@ test('collects tests with concurrent modifier in different order', async () => {
       "test outside concurrent suite": {
         "errors": [],
         "fullName": "test outside concurrent suite",
-        "id": "-1732721377_1",
+        "id": "1709388417_1",
         "location": "8:4",
         "mode": "run",
         "state": "pending",
@@ -1188,7 +1188,7 @@ test('collects tests with options object modifiers', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "options tests > concurrent via options",
-          "id": "-1732721377_0_3",
+          "id": "1709388417_0_3",
           "location": "8:6",
           "mode": "skip",
           "state": "skipped",
@@ -1196,7 +1196,7 @@ test('collects tests with options object modifiers', async () => {
         "only via options": {
           "errors": [],
           "fullName": "options tests > only via options",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "run",
           "state": "pending",
@@ -1205,7 +1205,7 @@ test('collects tests with options object modifiers', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "options tests > skip and concurrent via options",
-          "id": "-1732721377_0_4",
+          "id": "1709388417_0_4",
           "location": "9:6",
           "mode": "skip",
           "state": "skipped",
@@ -1213,7 +1213,7 @@ test('collects tests with options object modifiers', async () => {
         "skipped via options": {
           "errors": [],
           "fullName": "options tests > skipped via options",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "skip",
           "state": "skipped",
@@ -1221,7 +1221,7 @@ test('collects tests with options object modifiers', async () => {
         "todo via options": {
           "errors": [],
           "fullName": "options tests > todo via options",
-          "id": "-1732721377_0_2",
+          "id": "1709388417_0_2",
           "location": "7:6",
           "mode": "todo",
           "state": "skipped",
@@ -1249,7 +1249,7 @@ test('collects tests with concurrent modifier', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "concurrent suite > skipped in concurrent suite",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:6",
           "mode": "skip",
           "state": "skipped",
@@ -1258,7 +1258,7 @@ test('collects tests with concurrent modifier', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "concurrent suite > test in concurrent suite",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1268,7 +1268,7 @@ test('collects tests with concurrent modifier', async () => {
         "concurrent": true,
         "errors": [],
         "fullName": "concurrent test",
-        "id": "-1732721377_1",
+        "id": "1709388417_1",
         "location": "9:4",
         "mode": "run",
         "state": "pending",
@@ -1292,7 +1292,7 @@ test('collects tests with describe.concurrent.each', async () => {
           "concurrent": true,
           "errors": [],
           "fullName": "concurrent each %i > test inside concurrent each",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:6",
           "mode": "run",
           "state": "pending",
@@ -1319,7 +1319,7 @@ test('collects tests with test.concurrent.each', async () => {
           "each": true,
           "errors": [],
           "fullName": "suite > concurrent each test %i",
-          "id": "-1732721377_0_0-dynamic",
+          "id": "1709388417_0_0-dynamic",
           "location": "5:36",
           "mode": "run",
           "state": "pending",
@@ -1367,7 +1367,7 @@ test('@module-tag docs inject test tags', async () => {
         "test 1": {
           "errors": [],
           "fullName": "suite 1 > test 1",
-          "id": "492646822_0_0",
+          "id": "538223770_0_0",
           "location": "10:2",
           "mode": "run",
           "state": "pending",
@@ -1422,7 +1422,7 @@ test('collects tests with runIf modifier', async () => {
         "also conditional": {
           "errors": [],
           "fullName": "runIf tests > also conditional",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:22",
           "mode": "skip",
           "state": "skipped",
@@ -1430,7 +1430,7 @@ test('collects tests with runIf modifier', async () => {
         "runs conditionally": {
           "errors": [],
           "fullName": "runIf tests > runs conditionally",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:21",
           "mode": "skip",
           "state": "skipped",
@@ -1455,7 +1455,7 @@ test('collects tests with skipIf modifier', async () => {
         "also conditional skip": {
           "errors": [],
           "fullName": "skipIf tests > also conditional skip",
-          "id": "-1732721377_0_1",
+          "id": "1709388417_0_1",
           "location": "6:23",
           "mode": "skip",
           "state": "skipped",
@@ -1463,7 +1463,7 @@ test('collects tests with skipIf modifier', async () => {
         "skips conditionally": {
           "errors": [],
           "fullName": "skipIf tests > skips conditionally",
-          "id": "-1732721377_0_0",
+          "id": "1709388417_0_0",
           "location": "5:22",
           "mode": "skip",
           "state": "skipped",
@@ -1490,7 +1490,7 @@ test('collects tests with for modifier', async () => {
           "each": true,
           "errors": [],
           "fullName": "for tests > skipped for %i",
-          "id": "-1732721377_0_1-dynamic",
+          "id": "1709388417_0_1-dynamic",
           "location": "6:26",
           "mode": "skip",
           "state": "skipped",
@@ -1500,7 +1500,7 @@ test('collects tests with for modifier', async () => {
           "each": true,
           "errors": [],
           "fullName": "for tests > test with for %i",
-          "id": "-1732721377_0_0-dynamic",
+          "id": "1709388417_0_0-dynamic",
           "location": "5:24",
           "mode": "run",
           "state": "pending",
@@ -1527,7 +1527,7 @@ test('properties on test don\'t generate tests', async () => {
         "each": true,
         "errors": [],
         "fullName": "actual 2 test",
-        "id": "-1732721377_1-dynamic",
+        "id": "1709388417_1-dynamic",
         "location": "5:15",
         "mode": "run",
         "state": "pending",
@@ -1535,7 +1535,7 @@ test('properties on test don\'t generate tests', async () => {
       "actual 3 test": {
         "errors": [],
         "fullName": "actual 3 test",
-        "id": "-1732721377_2",
+        "id": "1709388417_2",
         "location": "6:4",
         "mode": "run",
         "state": "pending",
@@ -1543,7 +1543,7 @@ test('properties on test don\'t generate tests', async () => {
       "actual 4 test": {
         "errors": [],
         "fullName": "actual 4 test",
-        "id": "-1732721377_3",
+        "id": "1709388417_3",
         "location": "7:4",
         "mode": "run",
         "state": "pending",
@@ -1551,7 +1551,7 @@ test('properties on test don\'t generate tests', async () => {
       "actual test": {
         "errors": [],
         "fullName": "actual test",
-        "id": "-1732721377_0",
+        "id": "1709388417_0",
         "location": "4:4",
         "mode": "run",
         "state": "pending",

From 1e8e0a9f05072c7030171817a5a11ec2b3f94bd4 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:05:17 +0900
Subject: [PATCH 56/65] Wire blob reporter label option

Co-authored-by: Codex <noreply@openai.com>
---
 packages/runner/src/collect.ts                     |  2 +-
 packages/runner/src/types/runner.ts                |  2 +-
 packages/vitest/src/node/ast-collect.ts            |  4 ++--
 packages/vitest/src/node/config/resolveConfig.ts   |  9 +++++++++
 packages/vitest/src/node/config/serializeConfig.ts |  2 +-
 packages/vitest/src/node/project.ts                |  2 +-
 packages/vitest/src/node/reporters/blob.ts         |  3 ++-
 packages/vitest/src/node/test-specification.ts     |  2 +-
 packages/vitest/src/node/types/config.ts           |  8 +-------
 packages/vitest/src/runtime/config.ts              |  2 +-
 test/cli/test/reporters/merge-reports.test.ts      | 12 ++++--------
 11 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/packages/runner/src/collect.ts b/packages/runner/src/collect.ts
index 0b80d479f7f6..7d89da6a2915 100644
--- a/packages/runner/src/collect.ts
+++ b/packages/runner/src/collect.ts
@@ -53,7 +53,7 @@ export async function collectTests(
           config.name,
           runner.pool,
           runner.viteEnvironment,
-          { __vitest_label__: config.label },
+          { __vitest_label__: config.mergeReportsLabel },
         )
         file.tags = fileTags
         file.shuffle = config.sequence.shuffle
diff --git a/packages/runner/src/types/runner.ts b/packages/runner/src/types/runner.ts
index 05bd94b82fde..cd3fd571ab38 100644
--- a/packages/runner/src/types/runner.ts
+++ b/packages/runner/src/types/runner.ts
@@ -45,7 +45,7 @@ export interface VitestRunnerConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  label: string | undefined
+  mergeReportsLabel: string | undefined
 }
 
 /**
diff --git a/packages/vitest/src/node/ast-collect.ts b/packages/vitest/src/node/ast-collect.ts
index e3877882d767..8121d8e5ca80 100644
--- a/packages/vitest/src/node/ast-collect.ts
+++ b/packages/vitest/src/node/ast-collect.ts
@@ -288,7 +288,7 @@ export function createFailedFileTask(project: TestProject, filepath: string, err
     config.name,
     config.pool,
     undefined,
-    { typecheck: config.pool === 'typescript', __vitest_label__: config.label },
+    { typecheck: config.pool === 'typescript', __vitest_label__: config.mergeReportsLabel },
   )
   const file: ParsedFile = {
     ...baseFile,
@@ -342,7 +342,7 @@ function createFileTask(
     config.name,
     config.pool,
     undefined,
-    { typecheck: config.pool === 'typescript', __vitest_label__: config.label },
+    { typecheck: config.pool === 'typescript', __vitest_label__: config.mergeReportsLabel },
   )
   const file: ParsedFile = {
     ...baseFile,
diff --git a/packages/vitest/src/node/config/resolveConfig.ts b/packages/vitest/src/node/config/resolveConfig.ts
index fb2569c9db5e..f5eb49839e52 100644
--- a/packages/vitest/src/node/config/resolveConfig.ts
+++ b/packages/vitest/src/node/config/resolveConfig.ts
@@ -756,6 +756,15 @@ export function resolveConfig(
     }
   }
 
+  for (const reporter of resolved.reporters) {
+    if (Array.isArray(reporter) && reporter[0] === 'blob') {
+      const label = (reporter[1] as any)?.label
+      if (typeof label === 'string') {
+        resolved.mergeReportsLabel = label
+      }
+    }
+  }
+
   if (resolved.changed) {
     resolved.passWithNoTests ??= true
   }
diff --git a/packages/vitest/src/node/config/serializeConfig.ts b/packages/vitest/src/node/config/serializeConfig.ts
index dafeddb04129..1cb90dd6bfe4 100644
--- a/packages/vitest/src/node/config/serializeConfig.ts
+++ b/packages/vitest/src/node/config/serializeConfig.ts
@@ -144,7 +144,7 @@ export function serializeConfig(project: TestProject): SerializedConfig {
     tags: config.tags || [],
     tagsFilter: config.tagsFilter,
     strictTags: config.strictTags ?? true,
-    label: config.label,
+    mergeReportsLabel: config.mergeReportsLabel,
     slowTestThreshold:
       config.slowTestThreshold
       ?? globalConfig.slowTestThreshold
diff --git a/packages/vitest/src/node/project.ts b/packages/vitest/src/node/project.ts
index e1b984cf7d89..55d52853222e 100644
--- a/packages/vitest/src/node/project.ts
+++ b/packages/vitest/src/node/project.ts
@@ -555,7 +555,7 @@ export class TestProject {
       server.config,
     )
     this._config.api.token = this.vitest.config.api.token
-    this._config.label = this.vitest.config.label
+    this._config.mergeReportsLabel = this.vitest.config.mergeReportsLabel
     this._setHash()
     for (const _providedKey in this.config.provide) {
       const providedKey = _providedKey as keyof ProvidedContext
diff --git a/packages/vitest/src/node/reporters/blob.ts b/packages/vitest/src/node/reporters/blob.ts
index 9fb7c63265b0..036fbdbf5f62 100644
--- a/packages/vitest/src/node/reporters/blob.ts
+++ b/packages/vitest/src/node/reporters/blob.ts
@@ -14,6 +14,7 @@ import { getOutputFile } from '../../utils/config-helpers'
 
 export interface BlobOptions {
   outputFile?: string
+  label?: string
 }
 
 export class BlobReporter implements Reporter {
@@ -53,7 +54,7 @@ export class BlobReporter implements Reporter {
       const shard = this.ctx.config.shard
       const filename = [
         'blob',
-        this.ctx.config.label,
+        this.ctx.config.mergeReportsLabel,
         shard && `${shard.index}-${shard.count}`,
       ].filter(Boolean).join('-')
       outputFile = `.vitest-reports/${sanitizeFilePath(filename)}.json`
diff --git a/packages/vitest/src/node/test-specification.ts b/packages/vitest/src/node/test-specification.ts
index d0bdc43c0090..0d9cfaa85a75 100644
--- a/packages/vitest/src/node/test-specification.ts
+++ b/packages/vitest/src/node/test-specification.ts
@@ -63,7 +63,7 @@ export class TestSpecification {
     this.taskId = generateFileHash(
       relative(project.config.root, moduleId),
       projectName,
-      metaOverride ?? { typecheck: pool === 'typescript', __vitest_label__: project.config.label },
+      metaOverride ?? { typecheck: pool === 'typescript', __vitest_label__: project.config.mergeReportsLabel },
     )
     this.project = project
     this.moduleId = moduleId
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index a3ca9c739aa7..c8d552c850c5 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -968,11 +968,6 @@ export interface InlineConfig {
    */
   strictTags?: boolean
 
-  /**
-   * Label to disambiguate the same test file when merging blob reports from different environments
-   * @experimental
-   */
-  label?: string
 }
 
 export interface TypecheckConfig {
@@ -1152,7 +1147,6 @@ export interface ResolvedConfig
     | 'vmMemoryLimit'
     | 'fileParallelism'
     | 'tagsFilter'
-    | 'label'
   > {
   mode: VitestRunMode
 
@@ -1224,7 +1218,7 @@ export interface ResolvedConfig
   vmMemoryLimit?: UserConfig['vmMemoryLimit']
   dumpDir?: string
   tagsFilter?: string[]
-  label?: string
+  mergeReportsLabel?: string
 
   experimental: Omit<Required<UserConfig>['experimental'], 'importDurations'> & {
     importDurations: {
diff --git a/packages/vitest/src/runtime/config.ts b/packages/vitest/src/runtime/config.ts
index 7d2b7349c4e9..71d20844151f 100644
--- a/packages/vitest/src/runtime/config.ts
+++ b/packages/vitest/src/runtime/config.ts
@@ -146,7 +146,7 @@ export interface SerializedConfig {
   tags: TestTagDefinition[]
   tagsFilter: string[] | undefined
   strictTags: boolean
-  label: string | undefined
+  mergeReportsLabel: string | undefined
   slowTestThreshold: number | undefined
   isAgent: boolean
 }
diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index e59f7e746a5b..c0bd09ecebe1 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -508,8 +508,7 @@ test("macos only", () => {})
   const result1 = await runVitest({
     root,
     globals: true,
-    label: 'linux',
-    reporters: 'blob',
+    reporters: [['blob', { label: 'linux' }]],
   }, ['first', 'second'])
   expect(result1.stderr).toMatchInlineSnapshot(`""`)
   expect(result1.errorTree()).toMatchInlineSnapshot(`
@@ -530,8 +529,7 @@ test("macos only", () => {})
   const result2 = await runVitest({
     root,
     globals: true,
-    label: 'macos',
-    reporters: 'blob',
+    reporters: [['blob', { label: 'macos' }]],
   }, ['first', 'third'])
   expect(result2.stderr).toMatchInlineSnapshot(`""`)
   expect(result2.errorTree()).toMatchInlineSnapshot(`
@@ -692,8 +690,7 @@ test("works on browser", () => {
   }
   const result1 = await runVitest({
     ...baseConfig,
-    label: 'linux',
-    reporters: 'blob',
+    reporters: [['blob', { label: 'linux' }]],
   })
   expect(result1.stderr).toMatchInlineSnapshot(`""`)
   expect(result1.errorTree({ project: true })).toMatchInlineSnapshot(`
@@ -720,8 +717,7 @@ test("works on browser", () => {
   `)
   const result2 = await runVitest({
     ...baseConfig,
-    label: 'macos',
-    reporters: 'blob',
+    reporters: [['blob', { label: 'macos' }]],
   })
   expect(result2.stderr).toMatchInlineSnapshot(`""`)
   expect(result2.errorTree({ project: true })).toMatchInlineSnapshot(`

From d4be1881802ae395cb26fedf36761d53d5b7d30f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:10:15 +0900
Subject: [PATCH 57/65] Document blob reporter label option

Co-authored-by: Codex <noreply@openai.com>
---
 docs/.vitepress/config.ts                  |  4 --
 docs/config/label.md                       | 45 ----------------------
 docs/guide/cli-generated.md                |  7 ----
 docs/guide/cli.md                          |  3 +-
 docs/guide/improving-performance.md        | 18 ++++++++-
 docs/guide/reporters.md                    | 15 ++++++--
 packages/vitest/src/node/cli/cli-config.ts |  4 --
 7 files changed, 31 insertions(+), 65 deletions(-)
 delete mode 100644 docs/config/label.md

diff --git a/docs/.vitepress/config.ts b/docs/.vitepress/config.ts
index ceb6e2400cf1..67c88513bc74 100644
--- a/docs/.vitepress/config.ts
+++ b/docs/.vitepress/config.ts
@@ -336,10 +336,6 @@ export default ({ mode }: { mode: string }) => {
                 text: 'reporters',
                 link: '/config/reporters',
               },
-              {
-                text: 'label',
-                link: '/config/label',
-              },
               {
                 text: 'outputFile',
                 link: '/config/outputfile',
diff --git a/docs/config/label.md b/docs/config/label.md
deleted file mode 100644
index 1f722b61bcdc..000000000000
--- a/docs/config/label.md
+++ /dev/null
@@ -1,45 +0,0 @@
----
-title: label | Config
----
-
-# label <CRoot /> <Badge type="warning">experimental</Badge> <Version>4.1.3</Version>
-
-- **Type:** `string`
-- **CLI:** `--label=<label>`
-
-Label for the current test run. When set, the label is displayed alongside test results in the reporter output, and stored in the blob when using [`--reporter=blob`](/guide/reporters#blob-reporter).
-
-During [`--merge-reports`](/guide/cli#merge-reports), results from the same test files with different labels are kept as separate entries. The label is also included in the default blob output filename (e.g. `blob-linux.json`) to avoid collisions between runs on different machines.
-
-## Example
-
-Run with a label on each platform:
-
-```bash
-vitest run --reporter=blob --label=linux
-vitest run --reporter=blob --label=macos
-```
-
-Or set it via config, typically driven by an environment variable in CI:
-
-```ts [vitest.config.ts]
-import { defineConfig } from 'vitest/config'
-
-export default defineConfig({
-  test: {
-    label: `${process.platform}-${process.versions.node}`,
-    reporters: ['blob'],
-  },
-})
-```
-
-When merging, each label is displayed as a separate entry in the reporter output:
-
-```sh
-vitest --merge-reports
-
- ✓  linux  src/basic.test.ts (2 tests)
- ✓  macos  src/basic.test.ts (2 tests)
-```
-
-See [Blob Reporter](/guide/reporters#blob-reporter) and the [CI setup guide](/guide/improving-performance#sharding) for a full example.
diff --git a/docs/guide/cli-generated.md b/docs/guide/cli-generated.md
index 9617363ce678..633532489474 100644
--- a/docs/guide/cli-generated.md
+++ b/docs/guide/cli-generated.md
@@ -882,13 +882,6 @@ Start Vitest without running tests. Tests will be running only on change. If bro
 
 List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.
 
-### label
-
-- **CLI:** `--label <label>`
-- **Config:** [label](/config/label)
-
-Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--label=linux`).
-
 ### clearCache
 
 - **CLI:** `--clearCache`
diff --git a/docs/guide/cli.md b/docs/guide/cli.md
index 32fcfff11e3c..3ca490adbf78 100644
--- a/docs/guide/cli.md
+++ b/docs/guide/cli.md
@@ -224,8 +224,9 @@ vitest run --shard=3/3
 You cannot use this option with `--watch` enabled (enabled in dev by default).
 :::
 
+<!-- TODO: slop -->
 ::: tip
-If `--reporter=blob` is used without an output file, the default path will include the current shard config and [`label`](/config/label) to avoid collisions with other Vitest processes.
+If `--reporter=blob` is used without an output file, the default path will include the current shard config and blob reporter `label` option to avoid collisions with other Vitest processes.
 :::
 
 ### merge-reports
diff --git a/docs/guide/improving-performance.md b/docs/guide/improving-performance.md
index d3b4b5e15a63..696a17b6e731 100644
--- a/docs/guide/improving-performance.md
+++ b/docs/guide/improving-performance.md
@@ -132,6 +132,20 @@ Collect the results stored in `.vitest-reports` directory from each machine and
 vitest run --merge-reports
 ```
 
+When running the same shards across multiple environments, configure a blob reporter label so merged reports can display them separately:
+
+```ts [vitest.config.ts]
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    reporters: [
+      ['blob', { label: process.env.VITEST_BLOB_LABEL }],
+    ],
+  },
+})
+```
+
 ::: details GitHub Actions example
 This setup is also used at https://github.com/vitest-tests/test-sharding.
 
@@ -163,7 +177,9 @@ jobs:
         run: pnpm i
 
       - name: Run tests
-        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --label=${{ matrix.os }}
+        run: pnpm run test --reporter=blob --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }}
+        env:
+          VITEST_BLOB_LABEL: ${{ matrix.os }}
 
       - name: Upload blob report to GitHub Actions Artifacts
         if: ${{ !cancelled() }}
diff --git a/docs/guide/reporters.md b/docs/guide/reporters.md
index deaa83874124..5b908bce5c52 100644
--- a/docs/guide/reporters.md
+++ b/docs/guide/reporters.md
@@ -690,10 +690,19 @@ We recommend using this reporter if you are running Vitest on different machines
 npx vitest --merge-reports=reports --reporter=json --reporter=default
 ```
 
-When running the same tests across multiple environments, use the `--label` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
+<!-- TODO: slop. should we support VITEST_BLOB_LABEL? -->
+When running the same tests across multiple environments, use the blob reporter `label` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
 
-```bash
-vitest run --reporter=blob --label=linux
+```ts [vitest.config.ts]
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    reporters: [
+      ['blob', { label: process.env.VITEST_BLOB_LABEL }],
+    ],
+  },
+})
 ```
 
 Blob reporter output doesn't include file-based [attachments](/api/advanced/artifacts.html#testattachment).
diff --git a/packages/vitest/src/node/cli/cli-config.ts b/packages/vitest/src/node/cli/cli-config.ts
index 189033bf9590..a8823fa1c82b 100644
--- a/packages/vitest/src/node/cli/cli-config.ts
+++ b/packages/vitest/src/node/cli/cli-config.ts
@@ -845,10 +845,6 @@ export const cliOptionsConfig: VitestCLIOptions = {
     description: 'List all available tags instead of running tests. `--list-tags=json` will output tags in JSON format, unless there are no tags.',
     argument: '[type]',
   },
-  label: {
-    description: 'Label to disambiguate the same test file when merging blob reports from different environments (e.g. `--label=linux`).',
-    argument: '<label>',
-  },
   clearCache: {
     description: 'Delete all Vitest caches, including `experimental.fsModuleCache`, without running any tests. This will reduce the performance in the subsequent test run.',
   },

From 87782d61a90e4083e817d6879e44ff2a745be0e8 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:11:49 +0900
Subject: [PATCH 58/65] Use blob label option in test configs

Co-authored-by: Codex <noreply@openai.com>
---
 test/cli/vitest.config.ts | 3 +--
 test/core/vite.config.ts  | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/test/cli/vitest.config.ts b/test/cli/vitest.config.ts
index e714487f3904..0db8099139a6 100644
--- a/test/cli/vitest.config.ts
+++ b/test/cli/vitest.config.ts
@@ -7,10 +7,9 @@ export default defineConfig({
     reporters: [
       'verbose',
       ...(process.env.VITEST_CI_BLOB_LABEL
-        ? [['blob', {}] as any]
+        ? [['blob', { label: process.env.VITEST_CI_BLOB_LABEL }] as any]
         : []),
     ],
-    label: process.env.VITEST_CI_BLOB_LABEL,
     testTimeout: 60_000,
     isolate: false,
     fileParallelism: false,
diff --git a/test/core/vite.config.ts b/test/core/vite.config.ts
index 4d072f8e6e16..214ec64b35f5 100644
--- a/test/core/vite.config.ts
+++ b/test/core/vite.config.ts
@@ -130,10 +130,9 @@ export default defineConfig({
         ? [['default'], ['github-actions', { displayAnnotations: false }] as any]
         : [['default', { summary: true }], ['hanging-process']]),
       ...(process.env.VITEST_CI_BLOB_LABEL
-        ? [['blob']]
+        ? [['blob', { label: process.env.VITEST_CI_BLOB_LABEL }]]
         : []),
     ],
-    label: process.env.VITEST_CI_BLOB_LABEL,
     testNamePattern: '^((?!does not include test that).)*$',
     coverage: {
       provider: 'istanbul',

From 40e34d90cc1cc4492c6270164a394b0fa1076bee Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:13:25 +0900
Subject: [PATCH 59/65] chore: cleanup

---
 docs/guide/cli.md | 1 -
 1 file changed, 1 deletion(-)

diff --git a/docs/guide/cli.md b/docs/guide/cli.md
index 3ca490adbf78..ce33a27862ad 100644
--- a/docs/guide/cli.md
+++ b/docs/guide/cli.md
@@ -224,7 +224,6 @@ vitest run --shard=3/3
 You cannot use this option with `--watch` enabled (enabled in dev by default).
 :::
 
-<!-- TODO: slop -->
 ::: tip
 If `--reporter=blob` is used without an output file, the default path will include the current shard config and blob reporter `label` option to avoid collisions with other Vitest processes.
 :::

From ec698135397dc0736d463fac574903f1fa3add3f Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:17:40 +0900
Subject: [PATCH 60/65] Support VITEST_BLOB_LABEL

Co-authored-by: Codex <noreply@openai.com>
---
 docs/guide/cli.md                                |  2 +-
 docs/guide/improving-performance.md              | 14 +++-----------
 docs/guide/reporters.md                          | 11 ++++++++---
 packages/vitest/src/node/config/resolveConfig.ts | 10 ++++++++--
 4 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/docs/guide/cli.md b/docs/guide/cli.md
index ce33a27862ad..8434aaab3c67 100644
--- a/docs/guide/cli.md
+++ b/docs/guide/cli.md
@@ -225,7 +225,7 @@ You cannot use this option with `--watch` enabled (enabled in dev by default).
 :::
 
 ::: tip
-If `--reporter=blob` is used without an output file, the default path will include the current shard config and blob reporter `label` option to avoid collisions with other Vitest processes.
+If `--reporter=blob` is used without an output file, the default path will include the current shard config and blob label from `VITEST_BLOB_LABEL` or the blob reporter `label` option to avoid collisions with other Vitest processes.
 :::
 
 ### merge-reports
diff --git a/docs/guide/improving-performance.md b/docs/guide/improving-performance.md
index 696a17b6e731..82556b187f8a 100644
--- a/docs/guide/improving-performance.md
+++ b/docs/guide/improving-performance.md
@@ -132,18 +132,10 @@ Collect the results stored in `.vitest-reports` directory from each machine and
 vitest run --merge-reports
 ```
 
-When running the same shards across multiple environments, configure a blob reporter label so merged reports can display them separately:
+When running the same shards across multiple environments, set the `VITEST_BLOB_LABEL` environment variable so merged reports can display them separately:
 
-```ts [vitest.config.ts]
-import { defineConfig } from 'vitest/config'
-
-export default defineConfig({
-  test: {
-    reporters: [
-      ['blob', { label: process.env.VITEST_BLOB_LABEL }],
-    ],
-  },
-})
+```sh
+VITEST_BLOB_LABEL=linux vitest run --reporter=blob --shard=1/3
 ```
 
 ::: details GitHub Actions example
diff --git a/docs/guide/reporters.md b/docs/guide/reporters.md
index 5b908bce5c52..c80ce17fed73 100644
--- a/docs/guide/reporters.md
+++ b/docs/guide/reporters.md
@@ -690,8 +690,13 @@ We recommend using this reporter if you are running Vitest on different machines
 npx vitest --merge-reports=reports --reporter=json --reporter=default
 ```
 
-<!-- TODO: slop. should we support VITEST_BLOB_LABEL? -->
-When running the same tests across multiple environments, use the blob reporter `label` option to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
+When running the same tests across multiple environments, use the `VITEST_BLOB_LABEL` environment variable to distinguish each environment's blob. Vitest reads labels at merge time and displays results separately:
+
+```bash
+VITEST_BLOB_LABEL=linux vitest run --reporter=blob
+```
+
+You can also provide the label via the blob reporter option:
 
 ```ts [vitest.config.ts]
 import { defineConfig } from 'vitest/config'
@@ -699,7 +704,7 @@ import { defineConfig } from 'vitest/config'
 export default defineConfig({
   test: {
     reporters: [
-      ['blob', { label: process.env.VITEST_BLOB_LABEL }],
+      ['blob', { label: 'linux' }],
     ],
   },
 })
diff --git a/packages/vitest/src/node/config/resolveConfig.ts b/packages/vitest/src/node/config/resolveConfig.ts
index f5eb49839e52..47976c1e6587 100644
--- a/packages/vitest/src/node/config/resolveConfig.ts
+++ b/packages/vitest/src/node/config/resolveConfig.ts
@@ -756,14 +756,20 @@ export function resolveConfig(
     }
   }
 
+  let hasBlobReporter = false
+  let blobReporterLabel: string | undefined
   for (const reporter of resolved.reporters) {
     if (Array.isArray(reporter) && reporter[0] === 'blob') {
-      const label = (reporter[1] as any)?.label
+      hasBlobReporter = true
+      const { label } = reporter[1] as { label?: unknown }
       if (typeof label === 'string') {
-        resolved.mergeReportsLabel = label
+        blobReporterLabel = label
       }
     }
   }
+  if (hasBlobReporter) {
+    resolved.mergeReportsLabel = blobReporterLabel ?? process.env.VITEST_BLOB_LABEL
+  }
 
   if (resolved.changed) {
     resolved.passWithNoTests ??= true

From 717960f3e47aef66f2e6c3933f331a3636b4f312 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:18:57 +0900
Subject: [PATCH 61/65] deslop

---
 packages/vitest/src/node/config/resolveConfig.ts | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/packages/vitest/src/node/config/resolveConfig.ts b/packages/vitest/src/node/config/resolveConfig.ts
index 47976c1e6587..1527bdba8cc3 100644
--- a/packages/vitest/src/node/config/resolveConfig.ts
+++ b/packages/vitest/src/node/config/resolveConfig.ts
@@ -756,20 +756,15 @@ export function resolveConfig(
     }
   }
 
-  let hasBlobReporter = false
-  let blobReporterLabel: string | undefined
+  resolved.mergeReportsLabel = process.env.VITEST_BLOB_LABEL
   for (const reporter of resolved.reporters) {
     if (Array.isArray(reporter) && reporter[0] === 'blob') {
-      hasBlobReporter = true
-      const { label } = reporter[1] as { label?: unknown }
-      if (typeof label === 'string') {
-        blobReporterLabel = label
+      const options = reporter[1] as any
+      if (options && typeof options.label === 'string') {
+        resolved.mergeReportsLabel = options.label
       }
     }
   }
-  if (hasBlobReporter) {
-    resolved.mergeReportsLabel = blobReporterLabel ?? process.env.VITEST_BLOB_LABEL
-  }
 
   if (resolved.changed) {
     resolved.passWithNoTests ??= true

From 724e16818a83f31f86b53a70b9565d9ea05f7c32 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:34:28 +0900
Subject: [PATCH 62/65] deslop

---
 packages/vitest/src/node/types/config.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index c8d552c850c5..552423b6a476 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -967,7 +967,6 @@ export interface InlineConfig {
    * @default true
    */
   strictTags?: boolean
-
 }
 
 export interface TypecheckConfig {

From 51afc6efaeec65357f75a7cef76f1f7070e8b86d Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:37:16 +0900
Subject: [PATCH 63/65] Show blob labels only for merged reports

Co-authored-by: Codex <noreply@openai.com>
---
 packages/vitest/src/node/reporters/base.ts    | 4 ++--
 packages/vitest/src/node/reporters/summary.ts | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/vitest/src/node/reporters/base.ts b/packages/vitest/src/node/reporters/base.ts
index aec64e2ec106..132a83a9dd40 100644
--- a/packages/vitest/src/node/reporters/base.ts
+++ b/packages/vitest/src/node/reporters/base.ts
@@ -335,7 +335,7 @@ export abstract class BaseReporter implements Reporter {
       title += ` ${c.bgBlue(c.bold(' TS '))}`
     }
 
-    const label = entity.task.file.meta.__vitest_label__
+    const label = this.ctx.state.blobs && entity.task.file.meta.__vitest_label__
     if (label) {
       title += ` ${c.bgCyan(c.bold(` ${label} `))}`
     }
@@ -941,7 +941,7 @@ export abstract class BaseReporter implements Reporter {
           name += c.dim(` [ ${this.relative(filepath)} ]`)
         }
 
-        const label = task.file?.meta?.__vitest_label__
+        const label = this.ctx.state.blobs && task.file?.meta?.__vitest_label__
         this.ctx.logger.error(
           `${c.bgRed(c.bold(' FAIL '))} ${formatProjectName(project)}${label ? `${c.bgCyan(c.bold(` ${label} `))} ` : ''}${name}`,
         )
diff --git a/packages/vitest/src/node/reporters/summary.ts b/packages/vitest/src/node/reporters/summary.ts
index 3d144edd5848..11ac84ee6918 100644
--- a/packages/vitest/src/node/reporters/summary.ts
+++ b/packages/vitest/src/node/reporters/summary.ts
@@ -289,7 +289,7 @@ export class SummaryReporter implements Reporter {
 
     for (const testFile of Array.from(this.runningModules.values()).sort(sortRunningModules)) {
       const typecheck = testFile.meta.typecheck ? `${c.bgBlue(c.bold(' TS '))} ` : ''
-      const label = testFile.meta.__vitest_label__ ? `${c.bgCyan(c.bold(` ${testFile.meta.__vitest_label__} `))} ` : ''
+      const label = this.ctx.state.blobs && testFile.meta.__vitest_label__ ? `${c.bgCyan(c.bold(` ${testFile.meta.__vitest_label__} `))} ` : ''
       summary.push(
         c.bold(c.yellow(` ${F_POINTER} `))
         + formatProjectName({ name: testFile.projectName, color: testFile.projectColor })

From 39a13220e224de056b5d6720f443b33f8e936fa3 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 14:43:12 +0900
Subject: [PATCH 64/65] test: test new behavior of VITEST_BLOB_LABEL and
 original run reporter

---
 test/cli/test/reporters/merge-reports.test.ts | 46 ++++++++++++++++++-
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index c0bd09ecebe1..00c59746d40e 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -458,6 +458,7 @@ function trimReporterOutput(report: string) {
   // Trim start and end, capture just rendered tree
   rows.splice(0, 1 + rows.findIndex(row => row.includes('RUN  v')))
   rows.splice(rows.findIndex(row => row.includes('Start at')), 1)
+  rows.splice(rows.findIndex(row => row.includes('blob report written to')), 1)
 
   return rows.join('\n').trim()
 }
@@ -526,12 +527,53 @@ test("macos only", () => {})
     }
   `)
   process.env.TEST_LABEL_ENV = 'macos'
+  process.env.VITEST_BLOB_LABEL = 'macos' // test VITEST_BLOB_LABEL
   const result2 = await runVitest({
     root,
     globals: true,
-    reporters: [['blob', { label: 'macos' }]],
+    reporters: [
+      'blob',
+      // test the original run's reporter doesn't include label
+      'verbose',
+    ],
   }, ['first', 'third'])
-  expect(result2.stderr).toMatchInlineSnapshot(`""`)
+  delete process.env.VITEST_BLOB_LABEL
+  expect(trimReporterOutput(result2.stdout)).toMatchInlineSnapshot(`
+    "✓ first.test.ts > always good <time>
+     × first.test.ts > works on linux <time>
+       → expected false to be true // Object.is equality
+     ✓ first.test.ts > works on macos <time>
+     ✓ third.test.ts > macos only <time>
+
+     Test Files  1 failed | 1 passed (2)
+          Tests  1 failed | 3 passed (4)
+       Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)"
+  `)
+  expect(result2.stderr).toMatchInlineSnapshot(`
+    "
+    ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯
+
+     FAIL  first.test.ts > works on linux
+    AssertionError: expected false to be true // Object.is equality
+
+    - Expected
+    + Received
+
+    - true
+    + false
+
+     ❯ first.test.ts:5:50
+          3|
+          4| test("works on linux", () => {
+          5|   expect(process.env.TEST_LABEL_ENV === 'linux').toBe(true)
+           |                                                  ^
+          6| })
+          7|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯
+
+    "
+  `)
   expect(result2.errorTree()).toMatchInlineSnapshot(`
     {
       "first.test.ts": {

From 3c844537f38f15cef85a322395b53afdfbea424c Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 11 Apr 2026 15:20:51 +0900
Subject: [PATCH 65/65] test: cleanup logs

---
 test/cli/test/reporters/merge-reports.test.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/test/cli/test/reporters/merge-reports.test.ts b/test/cli/test/reporters/merge-reports.test.ts
index 00c59746d40e..ba70d3a32ea3 100644
--- a/test/cli/test/reporters/merge-reports.test.ts
+++ b/test/cli/test/reporters/merge-reports.test.ts
@@ -453,12 +453,12 @@ function trimReporterOutput(report: string) {
   const rows = report
     .replace(/\d+ms/g, '<time>')
     .replace(/\d+\.\d+s/g, '<time>')
+    .replace(/blob report written to (.*)/g, 'blob report written to <path>')
     .split('\n')
 
   // Trim start and end, capture just rendered tree
   rows.splice(0, 1 + rows.findIndex(row => row.includes('RUN  v')))
   rows.splice(rows.findIndex(row => row.includes('Start at')), 1)
-  rows.splice(rows.findIndex(row => row.includes('blob report written to')), 1)
 
   return rows.join('\n').trim()
 }
@@ -547,7 +547,9 @@ test("macos only", () => {})
 
      Test Files  1 failed | 1 passed (2)
           Tests  1 failed | 3 passed (4)
-       Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)"
+       Duration  <time> (transform <time>, setup <time>, import <time>, tests <time>, environment <time>)
+
+    blob report written to <path>"
   `)
   expect(result2.stderr).toMatchInlineSnapshot(`
     "