fix: enhance handling of MPX directive comments in Stylus formatting

[wangshunnn]

fix #99

This pull request enhances the handling of MPX directive comments within Stylus files by ensuring that these comments are preserved in their original positions during formatting. The main improvement is the introduction of logic to temporarily replace MPX directive comments with placeholders before formatting, and then restore them afterward, preventing the formatter from relocating these comments.

Preservation of MPX directive comments during formatting:

• Added a regular expression mpxDirectiveCommentRegex to accurately match MPX directive comments such as /* @mpx-if (...) */ and similar variants.
• Implemented logic to extract MPX directive comments, replace them with unique single-line placeholders before formatting, and restore them after formatting to maintain their original indentation and position.

Summary by CodeRabbit

• Bug Fixes
  • Fixed Stylus formatter to properly preserve MPX directive comments in style blocks, maintaining correct indentation and alignment during formatting operations.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds pre-processing and post-processing steps to Stylus formatting to preserve MPX directive comments. Introduces regex pattern to identify comments like /* @mpx-if (...) */, replaces them with placeholders before formatting, and restores the original comments afterward to prevent unwanted line breaks in conditional compilation directives.

Changes

Cohort / File(s)	Summary
Stylus Formatting Comment Preservation packages/language-service/src/plugins/mpx-sfc-style-stylus.ts	Added regex-based pre- and post-processing logic to preserve MPX directive comments during Stylus formatting. Comments are temporarily replaced with placeholders before formatter execution, then restored to their original form, preventing unwanted line breaks that would break conditional compilation.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• feat: support stylus formatting with stylus-supremacy #26: Introduced Stylus Supremacy-based formatting support that this PR now extends with comment preservation functionality.

Poem

🐰 Comments wrapped in stylus dreams,
Now preserved through formatting schemes,
No more breaks in directives bright,
Conditional logic stays just right! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: enhancing handling of MPX directive comments in Stylus formatting, which is the primary focus of the code changes.
Linked Issues check	✅ Passed	The code changes implement the core requirement from issue #99: preserving MPX directive comments in their original positions during Stylus formatting by using placeholder replacement and restoration logic.
Out of Scope Changes check	✅ Passed	All changes are directly related to the objective of preserving MPX directive comments in Stylus formatting; no unrelated or out-of-scope modifications are present.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix-stylus-comments-formatter

📝 Coding Plan

• Generate coding plan for human review comments

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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 `@packages/language-service/src/plugins/mpx-sfc-style-stylus.ts`:
- Around line 95-97: The placeholder "// __MPX_DIRECTIVE_${index}__" can collide
with user comments; modify the placeholder generation in this module (the code
that creates the placeholder variable and calls directiveComments.set) to use a
collision-proof token—e.g. append a random/unique suffix (crypto.randomUUID() or
a monotonic unique id combined with a hidden sentinel/unicode private-use
sequence) or otherwise encode metadata (index + uuid) so placeholders are
globally unique and unguessable; update all places that create or restore
placeholders (the placeholder variable, directiveComments.set(...) and the
corresponding restoration logic around lines referencing the same placeholder)
to use the new unique token format so restoration matches only generated
placeholders.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 25da8fed-d092-433c-b216-f836d01e79d5

📥 Commits

Reviewing files that changed from the base of the PR and between 656bd53 and edd7a2d.

📒 Files selected for processing (1)

• packages/language-service/src/plugins/mpx-sfc-style-stylus.ts