Build: remove accidental git submodule entries breaking actions/checkout

[Copilot]

Three paths under .external/ were registered in the git index as gitlink entries (mode 160000, the object type git uses for submodule references) with no corresponding .gitmodules file. This caused actions/checkout@v4 to fail during its git submodule foreach --recursive step:

fatal: No url found for submodule path '.external/addon-svelte-csf' in .gitmodules

Changes

• Remove broken gitlink entries — git rm --cached deregisters .external/addon-svelte-csf, .external/addon-webpack5-compiler-babel, and .external/addon-webpack5-compiler-swc from the tree (all three were empty placeholder directories with no submodule URL defined)
• Delete empty .external/ directories — nothing useful was there; the directories only existed as artifact of the stale index entries

This repo does not use git submodules. With these entries gone, git submodule foreach finds nothing to iterate and checkout proceeds cleanly.

Original prompt

Fix the failing Publish Canary Packages workflow in storybookjs/storybook by completely removing any accidental Git submodule configuration or behavior from the repo and from the workflow path introduced by PR #34799.

Context:

• Failing job: Publish Canary Packages
• Workflow run: 26162172935
• Job ID: 76956599895
• Failing commit SHA: c115b7fbe213b263402abfa49d77efedf59c02e9
• Error from job logs:
  • fatal: No url found for submodule path '.external/addon-svelte-csf' in .gitmodules
  • This happens during GitHub Actions post-job cleanup when actions/checkout@v4 runs git submodule foreach --recursive ...
• The user states this repository does not use submodules in any way, and any submodule config is a mistake that must be fully cleaned up.

What to investigate and fix:

1. Remove any tracked .gitmodules file if present on the PR branch or base branch, and remove any accidental submodule metadata/configuration references from the repository.
2. Inspect the new workflow .github/workflows/publish-canary.yml, especially the actions/checkout@v4 usage, and update it so checkout does not interact with submodules at all.
3. Search the repo for accidental references to .external/addon-svelte-csf, .gitmodules, or submodule-related configuration introduced by this PR or already present in the branch, and remove/neutralize them as needed.
4. Ensure the fix is minimal and safe: this repo should behave as a normal monorepo with directories only, not Git submodules.
5. If the root cause is index metadata rather than file content, add the necessary cleanup in the workflow/repo so CI no longer triggers any submodule logic for this repository.

Requirements:

• Create a pull request with the fix.
• Keep the solution narrowly focused on removing submodule behavior/configuration and unblocking the failing job.
• In the PR description or summary, mention the failing error and how the fix prevents submodule handling in this repo.
• If there are tests or validation steps relevant to workflow/config changes, include them.

Useful references:

• Failing workflow file: .github/workflows/publish-canary.yml
• The failure occurs after checkout, during post-job cleanup performed by actions/checkout.
• There was no .gitmodules file visible in the repository root listing for commit c115b7fbe213b263402abfa49d77efedf59c02e9, which suggests stale/accidental submodule metadata may exist in the PR branch/index or checkout behavior is surfacing it.

Please implement the fix directly in storybookjs/storybook against base branch next and open a PR.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: The job is currently failing with some git submodules issues. this repo does not use submodules in any way. if anything like that is configured - wrongly or not - it is a mistake. You must clean it up the git config/submodule stuff for this repo completely

Assistant: I’m waiting for your response to the confirmation dialog before I can continue with cleaning up the accidental git submodule handling and opening the fix PR.

This pull request was created from Copilot chat.

Summary by CodeRabbit

• Chores
  • Updated external dependencies and project configuration.

[github-actions]

	Fails
🚫	PR title must be in the format of "Area: Summary", With both Area and Summary starting with a capital letter Good examples: - "Docs: Describe Canvas Doc Block" - "Svelte: Support Svelte v4" Bad examples: - "add new api docs" - "fix: Svelte 4 support" - "Vue: improve docs"
🚫	PR description is missing the mandatory "#### Manual testing" section. Please add it so that reviewers know how to manually test your changes.

Generated by 🚫 dangerJS against a90e6dd

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 309a197b-8389-4dbc-90f1-0f145520545e

📥 Commits

Reviewing files that changed from the base of the PR and between 630f521 and a90e6dd.

📒 Files selected for processing (3)

• .external/addon-svelte-csf
• .external/addon-webpack5-compiler-babel
• .external/addon-webpack5-compiler-swc

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📝 Walkthrough

Walkthrough

Three git submodule references are removed from the .external/ directory: addon-svelte-csf and addon-webpack5-compiler-swc. This eliminates their recorded subproject commit pointers from the repository.

Changes

Submodule Cleanup

Layer / File(s)	Summary
Remove submodule references .external/addon-svelte-csf, .external/addon-webpack5-compiler-swc	Subproject commit entries are deleted for both external addon submodules, removing them from git tracking.

🎯 1 (Trivial) | ⏱️ ~2 minutes

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