fix(markdown_parser): restore leading-space stripping after hard line breaks by jfmcdowell · Pull Request #9934 · biomejs/biome

jfmcdowell · 2026-04-12T09:11:48Z

Note

This PR was created with AI assistance (Claude Code).

Summary

Follow-up to #9931. Fixes a regression from #9933 where hard breaks inside blockquotes stopped producing <br />, and continuation-line spaces after hard breaks were preserved in plain paragraphs.

For non-container paragraphs, the parser now strips CommonMark §6.7 continuation spaces before line-continuation handling. Container contexts are unchanged.

Test Plan

just test-crate biome_markdown_parser
just test-markdown-conformance
cargo test -p biome_markdown_formatter
just f

Docs

N/A

changeset-bot · 2026-04-12T09:11:54Z

⚠️ No Changeset found

Latest commit: fee71e4

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codspeed-hq · 2026-04-12T18:35:29Z

Merging this PR will not alter performance

✅ 28 untouched benchmarks
⏩ 228 skipped benchmarks¹

_{Comparing jfmcdowell:fix/md-container-hard-break (fee71e4) with main (9956f1d)}

228 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

coderabbitai · 2026-04-12T19:31:40Z

Walkthrough

Refactors paragraph-continuation and hard-line-break handling in the Markdown parser. Introduces handle_line_continuation to centralise checks (quote-prefix, setext/thematic underlines, list interrupts, nested-list marker/indent, fence/textual-block interrupts) and adjusts quote-blank-line probing so prefix markers aren’t consumed. handle_inline_newline and parse_inline_item_list now delegate to the new helper. Adds unit tests and HTML/MD fixtures covering hard breaks in blockquotes, list items and nested quote-in-list scenarios.

Possibly related PRs

fix(markdown_parser): paragraph with trailing hard break absorbs following blank line #9931 — Adjusts hard-break continuation in parse_inline_item_list, including treatment of bare NEWLINE after MD_HARD_LINE.
fix(markdown_parser): recognize setext heading inside blockquote #9782 — Refactors blockquote and quote-blank-line detection in the parser source shared by this change.
fix(markdown): preserve nested list indent tokens #9717 — Modifies continuation and inline-newline logic affecting nested-list indent and paragraph-break decisions.

Suggested reviewers

ematipico
dyc3

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarises the main fix: restoring leading-space stripping after hard line breaks in the Markdown parser, which directly addresses the regression described in the PR objectives.
Description check	✅ Passed	The description is directly related to the changeset, clearly explaining the regression from `#9933`, the specific fix applied, and how it restores CommonMark §6.7 continuation-space handling for non-container paragraphs.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

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coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@crates/biome_markdown_parser/src/syntax/mod.rs`:
- Around line 865-877: is_quote_blank_line_from_current currently mutates parser
state by calling consume_quote_prefix_without_virtual and p.bump while probing,
which can desynchronize later quote continuation checks; change the probe to be
non-mutating by making it operate on a snapshot or lookahead of the parser
(e.g., clone p or use a cursor/snapshot API) instead of bumping the real parser,
keeping the original checks (has_quote_prefix, MD_TEXTUAL_LITERAL whitespace
checks, NEWLINE/EOF detection) but performing them against the cloned/temporary
parser so consume_quote_prefix_without_virtual and p.bump are not invoked on the
live p.

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Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

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Review profile: CHILL

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Run ID: ba24faea-235c-4206-a8ea-46013b9bde9c

📥 Commits

Reviewing files that changed from the base of the PR and between 9956f1d and 29027e5.

⛔ Files ignored due to path filters (3)

crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_blockquote.md.snap is excluded by !**/*.snap and included by **
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_list_item.md.snap is excluded by !**/*.snap and included by **
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_nested_quote_in_list.md.snap is excluded by !**/*.snap and included by **

📒 Files selected for processing (8)

crates/biome_markdown_parser/src/syntax/mod.rs
crates/biome_markdown_parser/src/to_html.rs
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_blockquote.html
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_blockquote.md
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_list_item.html
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_in_list_item.md
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_nested_quote_in_list.html
crates/biome_markdown_parser/tests/md_test_suite/ok/hard_break_nested_quote_in_list.md

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In @.changeset/fix-markdown-quote-blank-line-probe.md:
- Line 5: Update the changeset text to mention both fixes: in addition to
"quoted hard-line-break handling" describe that the parser also restores
stripping continuation-line spaces after hard breaks in ordinary (plain)
paragraphs; edit the sentence in
.changeset/fix-markdown-quote-blank-line-probe.md to explicitly include
"plain-paragraph fix" or similar wording so the release note accurately reflects
both user-facing changes (quoted content behavior and plain paragraph
continuation-line space stripping).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 058e40cf-97b1-47e2-b8e4-131927b97443

📥 Commits

Reviewing files that changed from the base of the PR and between 29027e5 and 63460aa.

📒 Files selected for processing (3)

.changeset/fix-markdown-quote-blank-line-probe.md
crates/biome_markdown_parser/src/syntax/mod.rs
crates/biome_markdown_parser/tests/spec_test.rs

✅ Files skipped from review due to trivial changes (1)

crates/biome_markdown_parser/tests/spec_test.rs

coderabbitai · 2026-04-12T20:11:14Z

+"@biomejs/biome": patch
+---
+
+Fixed the Markdown parser's quoted hard-line-break handling so blank-line checks no longer consume quote prefixes while probing. This preserves correct continuation parsing for quoted content after hard breaks.


⚠️ Potential issue | 🟡 Minor

Please mention the plain-paragraph fix too.

The parser change also restores stripping continuation-line spaces after hard breaks in ordinary paragraphs, but this note only mentions quoted content. Worth folding both behaviours in so the release note matches what actually shipped. As per coding guidelines, "Changeset descriptions should focus on user-facing changes only".

🧰 Tools

🪛 LanguageTool

[uncategorized] ~5-~5: Possible missing comma found.
Context: ...arkdown parser's quoted hard-line-break handling so blank-line checks no longer consume ...

(AI_HYDRA_LEO_MISSING_COMMA)

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed. In @.changeset/fix-markdown-quote-blank-line-probe.md at line 5, Update the changeset text to mention both fixes: in addition to "quoted hard-line-break handling" describe that the parser also restores stripping continuation-line spaces after hard breaks in ordinary (plain) paragraphs; edit the sentence in .changeset/fix-markdown-quote-blank-line-probe.md to explicitly include "plain-paragraph fix" or similar wording so the release note accurately reflects both user-facing changes (quoted content behavior and plain paragraph continuation-line space stripping).

ematipico · 2026-04-12T20:11:35Z

What's this for? Mistake maybe?

Per maintainer feedback, these HTML reference files are not needed for the hard break parser fix.

github-actions bot added A-Parser Area: parser A-Formatter Area: formatter L-Markdown Language: Markdown labels Apr 12, 2026

jfmcdowell changed the title ~~fix(markdown_parser): restore §6.7 leading-space stripping after hard line breaks~~ fix(markdown_parser): restore leading-space stripping after hard line breaks Apr 12, 2026

jfmcdowell force-pushed the fix/md-container-hard-break branch 2 times, most recently from 581af4f to fb85ead Compare April 12, 2026 18:31

github-actions bot removed the A-Formatter Area: formatter label Apr 12, 2026

fix(markdown_parser): preserve hard breaks in nested containers

29027e5

jfmcdowell force-pushed the fix/md-container-hard-break branch from e703e33 to 29027e5 Compare April 12, 2026 19:09

jfmcdowell marked this pull request as ready for review April 12, 2026 19:26

coderabbitai bot reviewed Apr 12, 2026

View reviewed changes

Comment thread crates/biome_markdown_parser/src/syntax/mod.rs

fix(markdown_parser): avoid mutating quote blank-line probe

63460aa

coderabbitai bot reviewed Apr 12, 2026

View reviewed changes

chore: remove changeset for experimental parser fix

eb743d1

ematipico reviewed Apr 12, 2026

View reviewed changes

chore: remove unnecessary HTML sidecar test fixtures

fee71e4

Per maintainer feedback, these HTML reference files are not needed for the hard break parser fix.

ematipico approved these changes Apr 13, 2026

View reviewed changes

ematipico merged commit 77ad4a4 into biomejs:main Apr 13, 2026
17 checks passed

jfmcdowell deleted the fix/md-container-hard-break branch April 13, 2026 11:44

coderabbitai bot mentioned this pull request Apr 14, 2026

fix(markdown_parser): trim trailing newline in tight lists inside blockquotes #9976

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fix(markdown_parser): restore leading-space stripping after hard line breaks#9934

fix(markdown_parser): restore leading-space stripping after hard line breaks#9934
ematipico merged 4 commits intobiomejs:mainfrom
jfmcdowell:fix/md-container-hard-break

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Merging this PR will not alter performance

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