Respect Both `.gitignore` and `.prettierignore` Files

[GoodbyeNJN]

Preflight Checklist

• I have searched existing issues and this is not a duplicate
• This is a feature for the VS Code extension, not for Prettier's formatting behavior

Problem Description

When using this extension to format code, it only respects patterns in the .prettierignore file and ignores patterns from .gitignore. While you can specify an ignore file via the prettier.ignorePath setting, this doesn't allow both files to be considered simultaneously.

Proposed Solution

By default, respect patterns from both .gitignore and .prettierignore files. When patterns exist in both files, they should both be applied.

Alternatives Considered

Update the prettier.ignorePath setting to support multiple ignore file paths, for example:

{
    "prettier.ignorePath": [".gitignore", ".prettierignore"]
}

Additional Context

Since Prettier v3.0.0, it has respected both .gitignore and .prettierignore files by default (reference). However, this extension has only respected .prettierignore, creating an inconsistency in behavior. With the extension moving toward v12, this is a good opportunity to align it with Prettier's default behavior.

Related issue: #3361 and #3063

[saksham-sankhla04]

Hi, I would like to work on this

[exquz3me]

@saksham-sankhla04 any progress?

This is the same issue as #3063

[exquz3me]

PROPOSAL

Here's what I came up with:
the following changes have all tests passing and have backwards compatibility with V2.

Allow to use array format in ignorePath

// types.ts

export interface IExtensionConfig {
  //...
  ignorePath: string | string[];
  //...
}

Change default ignorePath setting to use array format

// package.json

"prettier.ignorePath": {
  //...
  "default": [
    ".gitignore",
    ".prettierignore"
  ],
  //...
}

// workspace.ts

if (!workspace.isTrusted) {
  const newConfig = {
      //...
      ignorePath: [".gitignore", ".prettierignore"],
      //...
    };
    return newConfig;
  }
}

Use a for of loop to populate resolvedIgnorePath, fallback to first index of array on V2

// PrettierEditService.ts

// Potential edge case here with user using ignorePath without `.gitignore`
const gitIgnoreWatcher = workspace.createFileSystemWatcher("**/.gitignore");
gitIgnoreWatcher.onDidChange(this.prettierConfigChanged);
gitIgnoreWatcher.onDidCreate(this.prettierConfigChanged);
gitIgnoreWatcher.onDidDelete(this.prettierConfigChanged);

//...

let resolvedIgnorePath: string | string[] | undefined;
if (vscodeConfig.ignorePath) {
  if (Array.isArray(vscodeConfig.ignorePath)) {
    if (isAboveV3(prettierInstance.version)) {
      // Prettier v3+ supports array of ignorePath
      resolvedIgnorePath = [];
      for (const ignorePath of vscodeConfig.ignorePath) {
        const resolved = await this.moduleResolver.getResolvedIgnorePath(
          fileName,
          ignorePath,
        );
        if (resolved) {
          resolvedIgnorePath.push(resolved);
        }
      }
    } else {
      // Prettier v2 only supports a single ignorePath
      this.loggingService.logError(
        "Multiple ignorePath values are not supported in Prettier v2. Using only the first ignorePath.",
      );
      const firstIgnorePath = vscodeConfig.ignorePath[0];
      resolvedIgnorePath = await this.moduleResolver.getResolvedIgnorePath(
        fileName,
        firstIgnorePath,
      );
    }
  } else {
    resolvedIgnorePath = await this.moduleResolver.getResolvedIgnorePath(
      fileName,
      vscodeConfig.ignorePath,
    );
  }

  if (resolvedIgnorePath) {
    if (Array.isArray(resolvedIgnorePath)) {
      if (resolvedIgnorePath.length > 0) {
        for (const ignorePath of resolvedIgnorePath) {
          this.loggingService.logInfo(
            `Using ignore file (if present) at ${ignorePath}`,
          );
        }
      }
    } else {
      this.loggingService.logInfo(
        `Using ignore file (if present) at ${resolvedIgnorePath}`,
      );
    }
  }
}