[detail-app]

Detail bug report: View on Detail

🎯 Changes

The matcher used by the injectSource.ignore.files / ignore.components config called pattern.test(s) directly on user-supplied RegExp objects. When a regex has the g (global) or y (sticky) flag, .test() is stateful and advances lastIndex on a successful match. Because the same regex object from the user's config is reused across every module transform (Vite transform hook and rspack loader) and every JSX-element check for the lifetime of a dev server/build, identical inputs produced alternating match/no-match results — so files/components the user asked to ignore were intermittently injected with data-tsd-source depending on module processing order.

Fix: matcher now clones any g/y-flagged regex without those stateful flags (preserving all other flags like i/m/s/u) so each .test() is stateless and deterministic. Flagless regexes pass through by identity, so the common documented cases are unchanged. The user's original config regex is never mutated (lastIndex stays 0).

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested code changes locally with pnpm test:pr, or these tests do not apply to this pull request.
• I fully understand the code in this pull request, including any code generated with AI assistance.

🚀 Release Impact

• This change affects published code, and I have generated a changeset.
• This change is docs/CI/dev-only (no release).

Testing

• Unit tests, typecheck (tsc --noEmit), lint (eslint ./src), and build (vite build + publint --strict) for @tanstack/devtools-bundler-core all pass. Downstream consumers @tanstack/devtools-vite and @tanstack/devtools-rspack typecheck cleanly against the updated package. The full devtools-bundler-core suite (13 files / 204 tests) is green, including the existing inject-source ignore-pattern tests (53 tests, no regression).
• Added regression tests in matcher.test.ts asserting that g- and y-flagged regexes stay deterministic across repeated calls with a shared regex object, and that the user's regex lastIndex is not mutated.
• End-to-end verification of the reported public-API symptom: a temporary (unversioned) test drove repeated addSourceToJsx(code, 'src/Foo.test.tsx', { files: [/\.test\.tsx$/g] }) calls sharing one config object — the exact code path the Vite plugin and rspack loader use per module. With the fix, the file is ignored on every call; with the fix reverted the suite reproduces the reported nondeterminism (call chore: remove unused a11y panel style keys #1 injects instead of ignoring, lastIndex advances to 16, and a file with multiple <Button/> elements intermittently gets data-tsd-source on a later element). The fix was restored before commit.
• A live Vite dev-server repro was not run: no existing example app uses injectSource, and the headless public-API test exercises the identical shared-config-reuse code path, with the revert control confirming the exact reported symptom.

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