trigger-workflow-dispatch: use return_run_details when available

As announced in the GitHub changelog at
https://github.blog/changelog/2026-02-19-workflow-dispatch-api-now-returns-run-ids/
the REST API's workflow dispatch endpoint now supports a boolean
`return_run_details` parameter that, when set to `true`, causes
the response to be a `200 OK` with a JSON body containing
`workflow_run_id`, `run_url`, and `html_url` instead of the
previous `204 No Content`.

This eliminates the need to poll for the workflow run after
triggering it, which was the root cause of the clock skew problems
that this branch set out to fix (the polling required a time-based
search window, and the response timestamp could come after the
workflow run's `created_at`).

The polling fallback is retained for robustness in case the API
regresses or the parameter is not honored. The test mock returns
the new `200` response for all dispatches except
`upload-snapshot.yml`, which still returns the `204`-style
response, so both code paths are exercised.

Assisted-by: Claude Opus 4.6
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

GitForWindowsHelper/trigger-workflow-dispatch.js

@@ -39,15 +39,19 @@ const triggerWorkflowDispatch = async (context, token, owner, repo, workflow_id,
     if ('true' === process.env.DO_NOT_TRIGGER_ANYTHING) {
         throw new Error(`Would have triggered workflow ${workflow_id} on ${owner}/${repo} with ref ${ref} and inputs ${JSON.stringify(inputs)}`)
     }
-    const { headers: { date } } = await githubApiRequest(
+    const response = await githubApiRequest(
         context,
         token,
         'POST',
         `/repos/${owner}/${repo}/actions/workflows/${workflow_id}/dispatches`,
-        { ref, inputs }
+        { ref, inputs, return_run_details: true }
     )
 
-    // to avoid any potential clock skew, we set the "after" time to 5 seconds before the current time
+    // If the API returned run details (200), use them directly
+    if (response.workflow_run_id) return response
+
+    // Fall back to polling if we got a 204 (no run details)
+    const date = response.headers?.date || new Date().toISOString()
     const after = new Date(Date.parse(date) - 5000).toISOString()
     const runs = await waitForWorkflowRun(context, owner, repo, workflow_id, after, token)
     return runs[0]

__tests__/index.test.js

@@ -91,6 +91,12 @@ let mockGitHubApiRequest = jest.fn((_context, _token, method, requestPath, paylo
             path: `.github/workflows/${match[1]}`,
             payload
         })
+        // Exercise the 204 fallback path for upload-snapshot.yml
+        if (payload?.return_run_details && match[1] !== 'upload-snapshot.yml') return {
+            workflow_run_id: 12345,
+            run_url: `https://api.github.com/repos/test/test/actions/runs/12345`,
+            html_url: `dispatched-workflow-${match[1]}`
+        }
         return {
             headers: {
                 date: (new Date()).toISOString()
@@ -338,14 +344,16 @@ The MINGW workflow run [was started](dispatched-workflow-open-pr.yml)`,
     expect(dispatchedWorkflows).toHaveLength(2)
     expect(dispatchedWorkflows.map(e => e.payload.inputs.package)).toEqual(['mingw-w64-gnutls', 'gnutls'])
     expect(mockGitHubApiRequest).toHaveBeenCalled()
-    const msysComment = mockGitHubApiRequest.mock.calls[mockGitHubApiRequest.mock.calls.length - 6]
+    const patchCalls = mockGitHubApiRequest.mock.calls.filter(c => c[2] === 'PATCH')
+    expect(patchCalls).toHaveLength(2)
+    const msysComment = patchCalls[0]
     expect(msysComment[3]).toEqual('/repos/git-for-windows/git/issues/comments/0')
     expect(msysComment[4]).toEqual({
         body: `existing comment body
 
 The MSYS workflow run [was started](dispatched-workflow-open-pr.yml)`
     })
-    const mingwComment = mockGitHubApiRequest.mock.calls[mockGitHubApiRequest.mock.calls.length - 1]
+    const mingwComment = patchCalls[1]
     expect(mingwComment[3]).toEqual('/repos/git-for-windows/git/issues/comments/0')
     expect(mingwComment[4]).toEqual({
         body: `existing comment body
@@ -834,7 +842,8 @@ The \`git-artifacts-aarch64\` workflow run [was started](dispatched-workflow-git
                 inputs: {
                     architecture: 'i686',
                     tag_git_workflow_run_id: "4322343196"
-                }
+                },
+                return_run_details: true
             }
         ])
     } catch (e) {
@@ -1041,7 +1050,8 @@ test('the third completed `git-artifacts-<arch>` check-run triggers an `upload-s
                     git_artifacts_aarch64_workflow_run_id: "13010016895",
                     git_artifacts_i686_workflow_run_id: "13010015938",
                     git_artifacts_x86_64_workflow_run_id: "13010015190"
-                }
+                },
+                return_run_details: true
             }
         ])
     } catch (e) {