fix: handle var() and env() in no-invalid-at-rules

[Pixel998]

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What did you do?

/* eslint css/no-invalid-at-rules: "error" */

@supports (padding: env(safe-area-inset-top)) {
	body {
		padding-top: env(safe-area-inset-top);
	}
}

What did you expect to happen?

No lint error. The prelude is valid, and the lexer does not support matching values containing env() or var(), so the rule should skip them, as no-invalid-properties already does for env().

What actually happened?

The rule crashed:

TypeError: Cannot read properties of null (reading '1')

What is the purpose of this pull request?

This PR makes no-invalid-at-rules skip preludes and descriptor values containing var() or env(), so they no longer crash the rule or get reported as unknown descriptors.

What changes did you make? (Give an overview)

• no-invalid-at-rules now returns early when the lexer reports it cannot match a prelude or descriptor value containing var() or env().
• Replaced isEnvMatchError, which compared CSSTree's message text and only covered env(), with isUnsupportedMatchingTreeError, which checks the error's name and covers both functions. no-invalid-properties now uses it.

Related Issues

refs #532 (its @supports env(safe-area-inset-top) {} test case crashes without this fix)

Is there anything you'd like reviewers to focus on?

Summary by CodeRabbit

• Bug Fixes

  • CSS validation now correctly handles unresolved var() and user-agent env() values in at-rule conditions and descriptors without reporting false errors.
  • Genuine syntax and other lexer errors continue to be reported as before.

• Tests

  • Added coverage for var() and env() usage in @supports conditions and @page descriptors.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

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Plan: Advanced

Run ID: dafd6a6a-92fe-4917-b7b8-025702706f1f

📥 Commits

Reviewing files that changed from the base of the PR and between 4b51c9e and 77250c3.

📒 Files selected for processing (4)

• src/rules/no-invalid-at-rules.js
• src/rules/no-invalid-properties.js
• src/util.js
• tests/rules/no-invalid-at-rules.test.js

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📝 Walkthrough

Walkthrough

The change replaces env()-specific lexer error detection with UnsupportedMatchingTree detection. At-rule and property validation now skip unresolved var() and env() values. Tests cover these at-rule cases.

Changes

Unsupported matching-tree handling

Layer / File(s)	Summary
Unsupported matching-tree predicate src/util.js	The utility detects UnsupportedMatchingTree errors by name and updates its type annotation.
Rule validation and coverage src/rules/no-invalid-at-rules.js, src/rules/no-invalid-properties.js, tests/rules/no-invalid-at-rules.test.js	The rules skip unsupported matching-tree errors for unresolved var() and env() values. Tests add valid @supports and @page cases.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Suggested reviewers: lumirlumir

🚥 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 accurately and concisely describes the main change: handling var() and env() in no-invalid-at-rules.
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 2 functions across 4 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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[DMartens]

Changes LGTM, thanks. Leaving open for others to review.