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xarmian
b6afbb8fca
The Go and JS wiki-link patterns were byte-identical source text and did not mean the same thing. Both spelled the escape alternative `\\.`, but Go's RE2 `.` excludes only LF while ECMAScript's also excludes CR, U+2028 and U+2029. A body with a backslash immediately before one of those three was INDEXED by the server and NOT RENDERED by the client: the backlink panel claimed a link the document refused to draw. CRLF line endings make the CR case the plausible one. Measured on both sides before deciding anything, over nine code points. Exactly three diverge; VT, FF and U+0085 agree, which bounds the divergence at precisely ECMAScript's LineTerminator set minus LF rather than leaving it open at "some whitespace controls". Aligns JS UP to Go (`\\[^\n]`) rather than narrowing Go, for three independent reasons: the grammar's other alternative already admits RAW CR/LS/PS in both languages, so narrowing Go would make `[[A<CR>B]]` legal and `[[A\<CR>B]]` illegal; narrowing Go would stop ExtractWikiLinks returning rows it currently returns, and the next reconcile would DELETE them, which is BUG-2805's damage shape; and markdown.ts's own splitWikiBody already treats `\<CR>` as an escape pair, so only its regex disagreed. LF stays excluded on both sides — scanBracketBody depends on that and is untouched. Also collapses the two duplicate regex literals in markdown.ts into one exported WIKI_LINK_PATTERN_SOURCE. Exported as source text, not a RegExp object, because a `/g` regex carries lastIndex and sharing one between a replace() and a test's exec() would couple them through it. The harness is the part meant to outlive the fix. testdata/wiki_grammar_corpus.json is read by BOTH languages, and carries expectations derived from the grammar spec rather than from either implementation — comparing the two implementations to each other would have reproduced the exact blind spot that hid this, since looking identical is what they already did. Pure ASCII with every control character as a \uXXXX escape: an early probe typed U+2028/U+2029 into a shell heredoc, silently lost them, and would have "confirmed" the bug on two cases that were actually spaces. JS assertions are split across the node and jsdom projects because renderMarkdown finishes through DOMPurify and returns '' without a DOM, where it would fail for a reason unrelated to the grammar. Same split, same reason, as the existing markdown.shareAttachments pair; the jsdom file carries a leg proving the DOM path is live, since '' satisfies every not.toContain assertion. Negative-controlled both ways: reverting the JS pattern fails exactly 9 assertions (3 corpus + 3 per call site) and nothing else; narrowing the GO pattern to JS semantics fails the same 3 cases from the other side, so both halves are live instruments rather than tests that cannot fail.