fix: local url DOCSTOOLS-6242

[goldserg]

Fixed a regression that caused a false error Unreachable link: "mailto:centru@datepersonale.md" when building.

Cause

Earlier in this session, url.parse() in packages/transform/src/transform/plugins/links/index.ts was replaced with the new helper parseHref from @diplodoc/utils. The problem turned out to be not in the helper itself, but in the existing function isLocalUrl, which was supposed to cut off external links (mailto:, tel: etc.) before calling parseHref/url.parse.

Its regex /^(?:[a-z]+:)?\/\//i catches only scheme://...`` and //host, but it **doesn't catch** "opaque" URI schemes without //, like mailto:foo@bar.md. Previously, this hole was masked by a side effect of legacy url.parse(): for mailto:centru@datepersonale.md, it parsed centruasauth, datepersonale.mdashost, and left pathnameasnull, and the code in the else { return; }branch silently skipped such a link. The newparseHref(as well as the correct WHATWG approach) does not use auth/host heuristics for schemes without//and returns the entire string aftermailto:aspathname. Since the string ends with .md, it passed the PAGE_LINK_REGEXP, and the code attempted to resolve it as a document file, resulting in an Unreachable link`.

Fix

In packages/transform/src/transform/utils.ts, isLocalUrl reuses the existing isExternalHref in the same file (the same logic as in the isExternalHref/isLocalUrl of the cli package, which correctly catches mailto:, tel:, and custom schemes regardless of the presence of //):

export function isLocalUrl(url: string) {
    return !isExternalHref(url);
}

Now such links are cut off at the earliest stage — before the call to parseHref — and marked as external (target="_blank", rel="noreferrer noopener"), as it was previously intended for external protocols.

Checking

• Added 2 regression tests in packages/transform/test/links.test.ts: for mailto:...md and tel:... — both confirm that the link remains external and does not attempt to resolve as a file.
• npx tsc --noEmit in packages/transform — clean.
• Full set of tests for the transform package: 971 passed | 1 skipped (was 969, +2 new).

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[yc-ui-bot]

Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
189	169	0	20	0	2	1m 56s

_{🎉 No failed tests in this run.}

Github Test Reporter by CTRF 💚