fix: warn when a style tag fails to compile

[cossssmin]

Follow-up to #1916.

When a <style> tag fails to compile, the tailwindcss transformer falls back to the uncompiled CSS, but it did so silently. Errors that @tailwindcss/postcss doesn't log itself (like a PostCSS parse error further down the pipeline) left no trace, and the email just came out unstyled.

It now logs a warning with the style tag number, the template path, and the error:

[maizzle] Failed to compile <style> #1 in /path/to/emails/welcome.vue, it was left uncompiled: <css input>:825:19: Missed semicolon

Output is unchanged: the tag still falls back to the uncompiled CSS, nothing throws. tailwindComponent already throws on failure, so it's left as is.

New test: a failing second <style> warns once, with the path and error, and still falls back.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • When a style tag fails to compile, the warning identifies its position and source file. The original CSS remains in the output as a fallback, preserving unresolved imports.

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• Configuration used: Organization UI
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Reviewing files that changed from the base of the PR and between d88bcfa and 31b6e65.

📒 Files selected for processing (2)

• src/tests/transformers/tailwindcss.test.ts
• src/transformers/tailwindcss.ts

🚧 Files skipped from review as they are similar to previous changes (2)

• src/tests/transformers/tailwindcss.test.ts
• src/transformers/tailwindcss.ts

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📝 Walkthrough

Walkthrough

The transformer records each encountered style tag’s position. When compilation fails, it logs a warning with the tag position, template location, and error details. The decoded CSS fallback remains in place.

Changes

Tailwind CSS compile-failure handling

Layer / File(s)	Summary
Warning and fallback behavior src/transformers/tailwindcss.ts, src/tests/transformers/tailwindcss.test.ts	The transformer tracks style tag positions and includes the failed tag’s position, template location, and error details in its warning. The existing decoded CSS fallback remains in place. The test checks the warning and unresolved import in the output.

Priority: ⬇️ Low

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

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 31b6e

A style tag that fails to compile now logs a warning with its tag number, template path and error. Output behavior stays the same. The change is low risk and ready to merge.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: emitting a warning when a style tag fails to compile.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
Review comments at @src/transformers/tailwindcss.ts:
- Line 263: Track each style tag’s position in the DOM walk, including raw and
empty tags, and use that source position in the compile-failure warning instead
of deriving the tag number from `i`. Locate the warning in the Tailwind CSS
style compilation flow and preserve its existing message details.

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: Organization UI
• Review profile: CHILL
• Plan: Advanced
• Run ID: 52015074-2e4b-46e6-88a2-aca768e05f28

📥 Commits

Reviewing files that changed from the base of the PR and between da3bff6 and d88bcfa.

📒 Files selected for processing (2)

• src/tests/transformers/tailwindcss.test.ts
• src/transformers/tailwindcss.ts

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 2 remain after this review.