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fix(metadata): reset lastIndex of unix manual page regex before testing #947

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fix(metadata): reset lastIndex of unix manual page regex before testing #947

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7 changes: 7 additions & 0 deletions .changeset/unix-manual-regex-lastindex.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
---
'@node-core/doc-kit': patch
---

Fix `isTextWithUnixManual` intermittently missing valid Unix manual page
references: the shared `unixManualPage` regex is global, so its `lastIndex`
persisted between `.test()` calls during tree traversal.
6 changes: 4 additions & 2 deletions src/utils/queries/index.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,8 +41,10 @@ export const UNIST = {
* @param {import('@types/mdast').Text} text
* @returns {boolean}
*/
isTextWithUnixManual: ({ type, value }) =>
type === 'text' && QUERIES.unixManualPage.test(value),
isTextWithUnixManual: ({ type, value }) => {
QUERIES.unixManualPage.lastIndex = 0; // Reset the lastIndex to ensure proper matching
return type === 'text' && QUERIES.unixManualPage.test(value);
},
Comment on lines +44 to +47

@avivkeller avivkeller Jul 27, 2026

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Can you give an example of something it would miss?

@btea btea Jul 28, 2026

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I dug into this, and honestly: with the current call chain, nothing is observably missed today. isTextWithUnixManual is only used as a visit() predicate (src/generators/metadata/utils/parse.mjs:142), and every successful .test() is immediately followed by the visitor's node.value.replace(QUERIES.unixManualPage, ...) (src/generators/metadata/utils/visitors.mjs:33, same regex instance)

RegExp.prototype[@@replace], step 9, on a global regex resets lastIndex to 0. A failing .test() also resets it, so lastIndex is always 0 at the start of each test. Verified empirically: pre-fix vs post-fix predicates over all of node/doc/api/*.md produce identical matches.

So this is hardening against shared mutable regex state, not a fix for a currently visible bug. Happy to add a small unit test calling the predicate twice to lock it in, or close if you'd rather not carry the extra line.


/**
* @param {import('@types/mdast').Link} link
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