fix(bundle): preserve root output path

[Lexiie]

Summary

resolveBundleDir('/') currently strips the trailing slash before checking whether the path is absolute. For the filesystem root path, that turns / into an empty string, so the helper resolves it against process.cwd() instead of preserving /.

This PR keeps the root path intact while preserving the existing behavior for ordinary trailing slashes like /tmp/bundle/.

Changes

• Only strip a trailing slash when the raw path has more than one character.
• Add regression coverage that resolveBundleDir('/') returns /.

Verification

• npm run format:check
• npm run typecheck
• npx vitest run src/lib/bundle.test.ts
• npx eslint src/lib/bundle.ts src/lib/bundle.test.ts

Summary by CodeRabbit

• Bug Fixes

  • Preserved the filesystem root path (/) when resolving bundle directories, avoiding it being reduced to an empty path.
  • Continued trimming trailing slashes for non-root paths as expected.

• Tests

  • Added coverage to verify root paths remain unchanged during bundle directory resolution.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 3305dfa and 40cf454.

📒 Files selected for processing (2)

• src/lib/bundle.test.ts
• src/lib/bundle.ts

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Walkthrough

This PR fixes resolveBundleDir in bundle.ts so that trailing-slash stripping only applies when the input path length exceeds 1, preserving the root path / instead of converting it to an empty string. A test case verifies this behavior.

Changes

Root Path Fix

Layer / File(s)	Summary
Trailing-slash normalization fix and test src/lib/bundle.ts, src/lib/bundle.test.ts	resolveBundleDir strips a trailing slash only when the path length is greater than 1, preserving '/'; a new test verifies resolveBundleDir('/') returns '/' unchanged.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Suggested reviewers: ruili-testsprite, zeshi-du

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main fix: preserving the filesystem root output path.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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