[eslint-changed] Fatal error on Windows when using `--git`

[rznn7]

Impacted plugin

None / Other

Quick summary

The package fails on Windows systems when running with --git options, throwing a fatal Git error about paths existing on disk but not in the index.

Environment

• OS: Windows (confirmed on 2 different laptops)
• Package version: 2.1.4
• Git: Git CLI (native Windows installation)
• Context: Running via lint-staged in a pre-commit hook

Trace (run with lint-staged)

✔ Backed up original state in git stash (9bbcfe76e)
⚠ Running tasks for staged files...
  ❯ lint-staged.config.mjs — 1 file
    ❯ *.ts — 1 file
      ✔ node scripts/eslint-fix-silent.js
      ✖ npx @automattic/eslint-changed --git --ext .ts [FAILED]
      ◼ prettier --write
    ↓ *.html — no files
    ↓ *.{json,css,scss,md} — no files
↓ Skipped because of errors from tasks.
✔ Reverting to original state because of errors...
✔ Cleaning up temporary files...
 
✖ npx @automattic/eslint-changed --git --ext .ts:
fatal: path 'app\src\app\path\to\file.ts' exists on disk, but not in the index
error: git exited with status 128
Error: lint-staged failed
husky - pre-commit script failed (code 1)

Steps to reproduce

1. On a Windows system, create or modify a TypeScript file in a Git repository
2. Stage the file: git add path/to/file.ts
3. Run the command: npx @automattic/eslint-changed --git --git-unstaged --ext .ts

Expected Behavior

The tool should successfully lint the staged changes without errors, as it does on Linux.

Actual Behavior

The command fails with:

fatal: path 'app\src\app\path\to\file.ts' exists on disk, but not in the index
error: git exited with status 128

Site owner impact

Fewer than 20% of the total website/platform users

Severity

Minor

What other impact(s) does this issue have?

No revenue impact

Additional information

• The same setup works perfectly on Linux
• The error specifically occurs when Git is asked to interact with a path that uses Windows-style backslashes (\)
• Git on Windows uses forward slashes (/) in its output, but the error message shows the path with backslashes
• This suggests a path separator normalization issue between Git's output format and Windows file system operations

Platform (Simple and/or Atomic)

No response

[anomiex]

I don't have access to Windows, so I'm unable to test this.

The error message quoted is from git itself, but it's not clear which git command it was trying to run. You might try running it with the --debug flag to get some additional output.

[rznn7]

Thanks for your answer, here is the same run with --debug flag.

PS C:\Users\user\Documents\dev\project-name\app> git commit -m "TEST" 
✔ Backed up original state in git stash (abc123def) 
✔ Hiding unstaged changes to partially staged files... 
⚠ Running tasks for staged files...   
  ❯ lint-staged.config.mjs — 1 file     
    ❯ *.ts — 1 file       
      ✔ node scripts/eslint-fix-silent.js       
      ✖ npx @automattic/eslint-changed --git --ext .ts --debug [FAILED]       
      ◼ prettier --write     
    ↓ *.html — no files     
    ↓ *.{json,css,scss,md} — no files 
↓ Skipped because of errors from tasks. 
↓ Skipped because of errors from tasks. 
✔ Reverting to original state because of errors... 
✔ Cleaning up temporary files...
 
✖ npx @automattic/eslint-changed --git --ext .ts --debug: 
fatal: path 'app\src\app\modules\feature-module\services\service-name.service.ts' exists on disk, but not in the index 
error: git exited with status 128 
Using ESLint version 8.57.1 
Using git version 2.51.0.windows.1 
Getting git top level: git rev-parse --show-toplevel 
Running git diff command: git diff --staged -- C:/Users/user/Documents/dev/project-name/app/src/app/modules/feature-module/services/service-name.service.ts 
Determined files from command line: app\src\app\modules\feature-module\services\service-name.service.ts 
Testing if file is new: git cat-file -e HEAD:app\src\app\modules\feature-module\services\service-name.service.ts 
It's new, so no orig ESLint data. 
Fetching new file contents: git show :0:app\src\app\modules\feature-module\services\service-name.service.ts 
Error: lint-staged failed 
husky - pre-commit script failed (code 1)

[anomiex]

Looks like your code is actually running something like npx @automattic/eslint-changed --git --ext .ts --debug C:/Users/user/Documents/dev/project-name/app/src/app/modules/feature-module/services/service-name.service.ts. Which is fine.

One more thing before I can make an attempt at a patch here. Can you run the git diff command from the output there and let me know the output?

Running git diff command: git diff --staged -- C:/Users/user/Documents/dev/project-name/app/src/app/modules/feature-module/services/service-name.service.ts

The contents of the change don't really matter if you want to make a dummy file that reproduces the problem instead of using live code.

[rznn7]

Here it is (also executed others commands listed in debug logs)

✖ npx @automattic/eslint-changed --git --ext .ts --debug:

fatal: path 'app\src\app\modules\feature-module\services\data-manager.service.ts' exists on disk, but not in the index
fatal: path 'app\src\app\modules\feature-module\services\data-manager.service.ts' exists on disk, but not in the index
error: git exited with status 128
Using ESLint version 8.57.1
Using git version 2.51.0.windows.1
Getting git top level: git rev-parse --show-toplevel
Running git diff command: git diff --staged -- C:/Users/jdoe/Documents/dev/my-project/app/src/app/modules/feature-module/services/data-manager.service.ts
Determined files from command line: app\src\app\modules\feature-module\services\data-manager.service.ts
Testing if file is new: git cat-file -e HEAD:app\src\app\modules\feature-module\services\data-manager.service.ts
It's new, so no orig ESLint data.
Fetching new file contents: git show :0:app\src\app\modules\feature-module\services\data-manager.service.ts
Error: lint-staged failed
husky - pre-commit script failed (code 1)

PS C:\Users\jdoe\Documents\dev\my-project> git diff --staged -- C:/Users/jdoe/Documents/dev/my-project/app/src/app/modules/feature-module/services/data-manager.service.ts
diff --git a/app/src/app/modules/feature-module/services/data-manager.service.ts b/app/src/app/modules/feature-module/services/data-manager.service.ts
index 56e7f1977..628ecefe8 100644
--- a/app/src/app/modules/feature-module/services/data-manager.service.ts
+++ b/app/src/app/modules/feature-module/services/data-manager.service.ts
@@ -281,6 +281,7 @@ export class DataManagerService {
     private readonly schemaServiceV2: SchemaServiceV2,
     private readonly nodePropertiesService: NodePropertiesService
   ) {
+    console.log('test')
     this.profilePictureEventBusService.profilePictureUpdated$.pipe(takeUntilDestroyed()).subscribe((event) => {
       this.updateNodePicture(event.entity, event.image);
     });

PS C:\Users\jdoe\Documents\dev\my-project> git rev-parse --show-toplevel
C:/Users/jdoe/Documents/dev/my-project

PS C:\Users\jdoe\Documents\dev\my-project> git cat-file -e HEAD:app\src\app\modules\feature-module\services\data-manager.service.ts
fatal: path 'app\src\app\modules\feature-module\services\data-manager.service.ts' exists on disk, but not in 'HEAD'

PS C:\Users\jdoe\Documents\dev\my-project> git show :0:app\src\app\modules\feature-module\services\data-manager.service.ts
fatal: path 'app\src\app\modules\feature-module\services\data-manager.service.ts' exists on disk, but not in the index

[anomiex]

Good, git diff is outputting forward-slashed names.

Can you see if #46180 fixes it for you?