Codemod: Fix glob pattern handling on Windows

[kasperpeulen]

Closes #

What I did

Fixed a Windows-specific bug where runCodemod in @storybook/codemod failed to find files because tinyglobby requires forward slashes in glob patterns, but path.join() on Windows produces backslash-separated paths.

The Bug

When running codemods on Windows, files were silently not being transformed because:

1. User or code provides a path like C:\Users\...\file.stories.tsx (or uses path.join() to construct it)
2. tinyglobby requires forward slashes for glob patterns
3. The backslash path doesn't match any files
4. Codemod reports "0 files" and does nothing

Root Cause

The cli-storybook version of runCodemod already handles this correctly using the slash package:

// code/lib/cli-storybook/src/automigrate/codemod.ts
const files = await globby(slash(globPattern), { ... });

But the @storybook/codemod version was missing this normalization:

// code/lib/codemod/src/index.ts (before fix)
const files = await tinyglobby([glob, '!**/node_modules', '!**/dist']);

The Fix

Use pathe.normalize() (already used throughout the codebase) to normalize paths before passing to tinyglobby:

// code/lib/codemod/src/index.ts (after fix)
import { normalize } from 'pathe';
// ...
const files = await tinyglobby([normalize(glob), '!**/node_modules', '!**/dist']);

How this was discovered

This pre-existing bug was exposed by the unit tests added in #33646. The tests use path.join(tmpdir(), ...) which produces backslash paths on Windows, causing the tests to fail on Windows CI (ci:daily). The bug itself has existed longer - it would have affected any Windows user calling the codemod with a backslash path.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

Caution

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

This was caught by the existing unit tests in src/index.test.ts which were failing on Windows CI (ci:daily). The fix makes those tests pass. This affects real Windows users, not just tests - anyone using npx storybook migrate on Windows with backslash paths would be affected.

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

Summary by CodeRabbit

• Bug Fixes
  • Fixed glob pattern path handling on Windows to ensure consistent use of forward-slash notation, improving cross-platform compatibility.
  • Improved reliability of file matching and downstream processing on Windows systems, reducing cases of missed or incorrectly processed files.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 5f4ed14

Command	Status	Duration	Result
nx run-many -t compile,check,knip,test,pretty-d...	❌ Failed	19m 50s	View ↗

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☁️ Nx Cloud last updated this comment at 2026-01-30 10:29:28 UTC

[coderabbitai]

Caution

Review failed

The pull request is closed.

📝 Walkthrough

Walkthrough

Imports normalize from pathe and applies it to glob patterns passed to tinyglobby, ensuring glob patterns use forward slashes on Windows and preserving existing filtering/processing logic.

Changes

Cohort / File(s)	Summary
Path Normalization code/lib/codemod/src/index.ts	Added normalize import from pathe and wrapped glob patterns with normalize(...) before building the tinyglobby file list to ensure consistent forward-slash globs on Windows.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

• Build: Fix build on windows #33224 — Also switches to using pathe/normalize for Windows-friendly path handling.
• Addon-Vitest: Normalize Windows paths in addon-vitest automigration #33340 — Adds pathe.normalize usage to convert Windows backslashes to forward slashes in path/glob handling.

✨ Finishing touches

• 📝 Generate docstrings

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