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fix: reject GFM email autolink when the domain ends in _ or - #4063

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Merged
UziTech merged 2 commits into from
Sep 4, 2026
Merged

fix: reject GFM email autolink when the domain ends in _ or - #4063

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294d257
fix: reject GFM email autolink when the domain ends in `_` or `-`
contactjawad Aug 20, 2026
fdfc48a
test: move email autolink regression test to the spec suite
contactjawad Aug 23, 2026
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2 changes: 1 addition & 1 deletion src/rules.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -524,7 +524,7 @@ const inlineGfm: Record<InlineKeys, RegExp> = {
delRDelim,
url: edit(/^((?:protocol):\/\/|www\.)(?:[a-zA-Z0-9\-]+\.?)+[^\s<]*|^email/)
.replace('protocol', _caseInsensitiveProtocol)
.replace('email', /[A-Za-z0-9._+-]+(@)[a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]*[a-zA-Z0-9])+(?![-_])/)
.replace('email', /[A-Za-z0-9._+-]+(@)[a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]*[a-zA-Z0-9])+(?![\w-])/)
.getRegex(),
_backpedal: /(?:[^?!.,:;*_'"~()&]+|\([^)]*\)|&(?![a-zA-Z0-9]+;$)|[?!.,:;*_'"~)]+(?!$))+/,
del: /^(~~?)(?=[^\s~])((?:\\[\s\S]|[^\\])*?(?:\\[\s\S]|[^\s~\\]))\1(?=[^~]|$)/,
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30 changes: 30 additions & 0 deletions test/unit/Lexer.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2118,6 +2118,36 @@ paragraph
],
});
});

it('url email domain ending in _ or - is not autolinked (GFM)', () => {
// A domain must not end in `_` or `-`; the whole email autolink is
// rejected and rendered as plain text, with the domain kept intact.
expectInlineTokens({
md: 'foo@bar.com_',
options: { gfm: true },
tokens: [
{
type: 'text',
raw: 'foo@bar.com_',
text: 'foo@bar.com_',
escaped: false,
},
],
});

expectInlineTokens({
md: 'foo@bar.com-',
options: { gfm: true },
tokens: [
{
type: 'text',
raw: 'foo@bar.com-',
text: 'foo@bar.com-',
escaped: false,
},
],
});
});
});

it('text', () => {
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