fix: drop a quadratic regex from the fake file watcher - #31
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`/\/+$/` stripping trailing separators is polynomial: the engine retries the greedy `\/+` from every position before `$` rejects it, so a base path of n separators costs time in n². CodeQL flags it as `js/polynomial-redos`, high. **It is not a vulnerability here** and the commit should not pretend otherwise. The input is `pattern.baseUri.path` from a `RelativePattern` the *test author* constructed — there is no untrusted path into a fake. What makes it worth fixing is that `src/testing/` is published code, the defect is real regardless of who can reach it, and counting backwards is both linear and easier to read than the regex was. Behaviour is identical: same trailing separators removed, and the existing watcher suites cover it. Verified: quality, verify:package, and both real-host lanes. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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/\/+$/stripping trailing separators is polynomial: the engine retries thegreedy
\/+from every position before$rejects it, so a base path of nseparators costs time in n². CodeQL flags it as
js/polynomial-redos, high.It is not a vulnerability, and this PR should not pretend otherwise
The input is
pattern.baseUri.pathfrom aRelativePatternthe test authorconstructed. There is no untrusted path into a fake — reaching this needs you
to write the base URI yourself, in your own test.
What makes it worth fixing anyway:
src/testing/is published code, not internal scaffoldingScope
One
replacebecomes a named helper. Same trailing separators removed, sameresult for every input; the existing watcher suites cover it. The only other
+$insrc/is base64 padding inhtml.ts, bounded at two characters — notflagged, and correctly so.
Verification
quality,verify:package, and both real-host lanes (Extension Host and web).🤖 Generated with Claude Code