fix(message-parser): keep URL underscores from closing link-text emphasis

[AlgoArtist06]

Proposed changes (including videos or screenshots)

Prevents an unmatched underscore in Markdown link text from treating an underscore in the URL as its emphasis closer.

Adds the exact reported regression case and a patch changeset for @rocket.chat/message-parser.

Keeps the change scoped to the message parser.

Issue(s)

Fixes #41725

Related to #41727

Steps to test or reproduce

1. Post [test-with-a-text-containing-an_here](http://example.com?param=my_value) in a channel.
2. Confirm only test-with-a-text-containing-an_here is displayed and the whole label links to http://example.com?param=my_value.
3. Run corepack yarn workspace @rocket.chat/message-parser test --runInBand with Node 22.22.3.

Further comments

Local verification:

• Message parser tests: 36 suites passed, 719 tests passed.
• Message parser lint: passed with 0 errors and 6 existing warnings.
• Message parser typecheck: passed.
• Message parser build: passed.

The full Rocket.Chat monorepo test suite was not run because it is impractical for this focused parser change.

Summary by CodeRabbit

• Bug Fixes

  • Fixed Markdown links so labels and URLs containing underscores are parsed and displayed correctly.

• Tests

  • Added coverage for links containing hyphens and underscores.

[dionisio-bot]

Looks like this PR is not ready to merge, because of the following issues:

• This PR is missing the 'stat: QA assured' label
• This PR is missing the required milestone or project

Please fix the issues and try again

If you have any trouble, please check the PR guidelines

[changeset-bot]

🦋 Changeset detected

Latest commit: f4526e4

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@rocket.chat/message-parser	Patch
@rocket.chat/gazzodown	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[coderabbitai]

Walkthrough

The message parser now preserves underscores in Markdown link labels when the URL also contains underscores. A parser test covers the link syntax, and a patch changeset documents the fix.

Changes

Message parser link fix

Layer / File(s)	Summary
Link title parsing and validation packages/message-parser/src/grammar.pegjs, packages/message-parser/tests/link.test.ts, .changeset/calm-links-render.md	LinkTitle handles the affected leading underscore pattern as plain text. The test verifies the complete link label and URL. The changeset records a patch release for @rocket.chat/message-parser.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• RocketChat/Rocket.Chat#41726: Addresses related Markdown hyperlink parsing when underscores appear in link text and URLs.
• RocketChat/Rocket.Chat#41727: Modifies and tests related underscore handling in Markdown hyperlink parsing.

Suggested labels: type: bug

Suggested reviewers: ggazzo

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The grammar fix and regression test address incorrect hyperlink rendering when both link text and URL contain underscores [#41725].
Out of Scope Changes check	✅ Passed	The changeset, parser update, and regression test are all within the linked issue scope.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the parser fix for underscores in link text and URLs.

Warning

Review ran into problems

🔥 Problems

Errors were encountered while retrieving linked issues.

Errors (1)

• UNDERSCORES-20260810: Request failed with status code 401

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[cubic-dev-ai]

No issues found across 3 files

_{Re-trigger cubic}

[AlgoArtist06]

Cross-linking the other open PRs on #41725 so a maintainer does not have to untangle this:

• fix: enhance link title parsing with hyphens and underscores in URL's #41739 by @Vaishali021103 changes the same two files (grammar.pegjs, tests/link.test.ts).
• fix: Wrong display of hyperlinks when an underscore is present in the text #41727 by @Ronak1167 was opened for the same bug, though its branch now carries unrelated changes (emoji, modals, NotFoundState) rather than a parser fix.

Only one of these should land. Happy to close this one if either of the others is preferred.