CLI: Match Storybook instances across Windows drive-letter case

[JReinhold]

Closes #

What I did

On Windows, storybook tools --cwd c:\project did not attach to a live instance whose record stored C:/project. node:path.resolve keeps the input drive-letter case, so the reader treated them as different projects and fell back to local tools.

This change compares project cwd/configDir with a Windows-aware equality helper (case-insensitive after resolve, including C: vs c: and \ vs /). POSIX compares stay byte-exact. The same helper is used for instance matching, attach fidelity, and the local vs child-host cwd check.

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!

Run these on native Windows. A Vite React Storybook is enough (sandbox or any local app).

1. From the project directory, start Storybook on a known port, e.g. npx storybook dev -p 6106 --ci. Wait until it is ready.

2. Confirm %USERPROFILE%\.storybook\instances\*.json for that process has cwd like C:/... (forward slashes, uppercase drive) and mcp.status of ready.

3. In a different directory (e.g. %USERPROFILE%), run each of these. docs list can stay on local fallback; watch stderr for attach:

   npx storybook tools --cwd C:\path\to\project docs list
   npx storybook tools --cwd C:/path/to/project docs list
   npx storybook tools --cwd c:\path\to\project docs list
   npx storybook tools --cwd c:/path/to/project docs list
   

4. Expected: none of the four print Running Storybook instances that did not match this project for this instance. Then npx storybook tools --cwd c:\path\to\project stories preview --input "{\"stories\":[{\"storyId\":\"<a-real-story-id>\"}]}" should return a URL on port 6106.

Worth extra scrutiny: a second Storybook on another path must still be reported as unmatched; POSIX path case (/Users/x/foo vs /Users/x/Foo) must still not match.

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

• Declare whether manual QA will be needed for this PR during the next release, through qa:needed or qa:skip

• 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>

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• code/core/src/cli/tools/sdk/create-tools.ts
• code/core/src/cli/tools/sdk/fidelity.test.ts
• code/core/src/cli/tools/sdk/fidelity.ts

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---

Walkthrough

Project path comparisons now resolve both inputs and apply Windows case normalization while keeping POSIX comparisons case-sensitive. Instance resolution, tool creation, fidelity checks, and local runtime validation use the shared helper. Tests cover both platform behaviors.

Changes

Project path matching

Layer / File(s)	Summary
Path equality contract code/core/src/cli/tools/instances/project-path.ts, code/core/src/cli/tools/instances/project-path.test.ts, code/core/src/cli/tools/test-support/mock-node-path.ts	Adds projectPathsEqual, which resolves paths and lowercases Windows results. Tests and mocks cover Windows and POSIX behavior.
Instance resolution matching code/core/src/cli/tools/instances/resolve.ts, code/core/src/cli/tools/instances/resolve.test.ts	Uses normalized equality for project cwd and configDir matching. Tests cover equivalent and distinct paths on Windows and POSIX.
SDK path consumers code/core/src/cli/tools/sdk/create-tools.ts, code/core/src/cli/tools/sdk/fidelity.ts, code/core/src/cli/tools/sdk/fidelity.test.ts, code/core/src/cli/tools/sdk/local-runtime.ts	Uses normalized equality when selecting tool execution mode, checking fidelity, and validating the local runtime project directory. Tests cover platform-specific matching.

Merge Risk: 🟡 Moderate · up to ee1b9

The PR improves Windows path matching, but a Windows-specific regression test is still expected to fail because it compares incompatible paths. Merge readiness is therefore blocked until that test is corrected.

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Actionable comments posted: 1

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Inline comments:
In `@code/core/src/cli/tools/sdk/fidelity.test.ts`:
- Line 69: Update the Windows regression test around checkFidelity to derive
flipped from process.cwd() rather than storybookFile, and pass the original
working directory as the cwd value so the expected fidelity result uses matching
paths.

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⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Essentials

Run ID: e6e58cf6-cba0-4b43-8f61-00fc24ef8fd2

📥 Commits

Reviewing files that changed from the base of the PR and between c1b9f62 and 912ca12.

📒 Files selected for processing (10)

• code/core/src/cli/tools/instances/project-path.test.ts
• code/core/src/cli/tools/instances/project-path.ts
• code/core/src/cli/tools/instances/resolve.test.ts
• code/core/src/cli/tools/instances/resolve.ts
• code/core/src/cli/tools/sdk/child-client.test.ts
• code/core/src/cli/tools/sdk/create-tools.ts
• code/core/src/cli/tools/sdk/fidelity.test.ts
• code/core/src/cli/tools/sdk/fidelity.ts
• code/core/src/cli/tools/sdk/local-runtime.ts
• code/core/src/cli/tools/test-support/mock-node-path.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.