fix(markdown): fix false diagnostic on nested lists with double blank lines

[jfmcdowell]

Note

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

Summary

Fix false "Expected a list item" diagnostic emitted when nested list items are separated by two or more blank lines.

The blank-line skip loop in has_list_item_after_blank_lines_at_indent consumed leading whitespace on the content line during blank-line detection, leaving the subsequent indent counter at 0. This caused indent validation to fail for nested lists where expected_indent > 0, which in turn prevented skip_blank_lines_between_items from recognizing the next sibling item.

Merged indent tracking into the skip loop so the indent is correctly measured from the whitespace consumed on the final (non-blank) line.

Added a regression in crates/biome_markdown_parser/tests/spec_test.rs covering nested sibling items after blank lines.

Test Plan

• just test-crate biome_markdown_parser — all passed
• just test-crate biome_markdown_formatter — all passed
• just test-markdown-conformance — 652/652
• just f
• just l

Docs

N/A.

[changeset-bot]

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Latest commit: 9aa5f21

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[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between bf16d9b and 9aa5f21.

⛔ Files ignored due to path filters (1)

• crates/biome_markdown_parser/tests/md_test_suite/ok/nested_list_double_blank.md.snap is excluded by !**/*.snap and included by **

📒 Files selected for processing (1)

• crates/biome_markdown_parser/tests/md_test_suite/ok/nested_list_double_blank.md

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

• crates/biome_markdown_parser/tests/md_test_suite/ok/nested_list_double_blank.md

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Walkthrough

The list blank-line lookahead in the markdown parser was changed to compute indentation while consuming blank lines instead of doing a separate post-skip pass. has_list_item_after_blank_lines_at_indent now accumulates indent across traversed blank lines and uses that tracked value for the marker-indent range check. Three tests and a markdown fixture were added to verify nested unordered-list behaviour across varying counts of blank lines.

Possibly related PRs

• fix(markdown): preserve nested list indent tokens #9717: Modifies blank-line lookahead and marker-indent computation in crates/biome_markdown_parser/src/syntax/list.rs — directly overlaps the same logic.
• refactor(markdown): emit continuation indent as structural CST node #9737: Adjusts list indentation handling (emits continuation indent nodes and changes indent emission), touching the same parser list-indent area.
• test(markdown): add regression tests for mixed list markers across blank lines #9732: Refactors blank-line lookahead and how marker/indent state is tracked across skipped blank lines in the list parser.

Suggested reviewers

• dyc3
• ematipico

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title clearly and specifically summarizes the main fix: addressing false diagnostics on nested lists when separated by double blank lines.
Description check	✅ Passed	The description is comprehensive and directly related to the changeset, explaining the bug, the root cause, the fix applied, and test coverage added.

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[codspeed-hq]

Merging this PR will not alter performance

✅ 28 untouched benchmarks
⏩ 228 skipped benchmarks¹

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_{Comparing jfmcdowell:fix/markdown-double-blank-nested-list (9aa5f21) with main (716e4e1)}

Footnotes

1. 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. ↩