Fix `function-url-quotes` false positives when URLs require quoting #8804

taearls · 2025-10-11T17:22:55Z

Which issue, if any, is this issue related to?

Closes #8544.

Is there anything in the PR that needs further explanation?

Changes made:

Added test cases covering the bug (unquoted URLs with special characters that require quotes)
Fixed the rule to not report errors when quotes are required in url() functions

Scope note: This PR focuses on fixing the false positive when quotes are required. It does not add validation for proper escaping of URL values.

Add test cases demonstrating bug stylelint#8544 where the `function-url-quotes: "never"` rule incorrectly flags URLs that require quotes for valid CSS. The failing tests cover three scenarios where quotes are required: - Data URIs with embedded quotes (e.g., SVG with attributes) - URLs containing spaces - URLs containing parentheses These tests currently fail because the rule doesn't check whether quotes are syntactically required before reporting violations. Refs: stylelint#8544 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>

Fix bug stylelint#8544 where the `function-url-quotes: "never"` rule incorrectly flagged URLs that must be quoted for valid CSS. The rule now detects when quotes are syntactically required and skips reporting violations in those cases. Implementation: - Added `quotesRequired()` helper function that checks for characters requiring quotes (spaces, quotes, parentheses) per CSS specification - Modified `checkArgs()` to extract URL content and check if quotes are required before reporting violations - When quotes are required, the rule returns early and does not report errors or attempt autofix This prevents the rule from generating invalid CSS when autofix is applied to URLs with embedded quotes (e.g., data URIs), spaces, or parentheses. All existing tests continue to pass, and the 6 new test cases now pass. Fixes stylelint#8544 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>

Update the CommonJS build output for the function-url-quotes rule to include the bug fix from the previous commit. This was generated by running the build process (rollup) which transpiles the ESM source (index.mjs) to CJS format. The generated file includes: - quotesRequired() helper function - Updated checkArgs() logic to detect required quotes - Early return when quotes are syntactically required This ensures the bug fix works for both ESM and CJS consumers of stylelint. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>

changeset-bot · 2025-10-11T17:22:58Z

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Latest commit: 237614f

The changes in this PR will be included in the next version bump.

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romainmenke

@taearls Thank you for working on this.

I've left a few suggestion to improve this change.
Please take a look when you have time.

lib/rules/function-url-quotes/index.mjs

romainmenke

Thank you for applying the feedback @taearls 🙇
I've left a few more suggestions to cover more cases and simplify the code.

lib/rules/function-url-quotes/index.mjs

github-actions · 2025-11-26T17:54:05Z

This PR is packaged and the instant preview is available (237614f). View the demo website.

Install it locally:

npm i -D https://pkg.pr.new/stylelint@237614f

romainmenke

Thank you. LGTM 👍

The codecov warning is caused by a redundant null-isch check, but TypeScript requires the check anyway. I think it is fine to merge as-is.

I'll merge this tomorrow to leave other maintainers a bit of time to also take a look.

jeddy3

LGTM, thank you!

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

@romainmenke

| datasource | package | from | to | | ---------- | --------- | ------- | ------- | | npm | stylelint | 16.26.0 | 16.26.1 | ## [v16.26.1](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16261---2025-11-28) It fixes numerous false positive bugs, including many in the `declaration-property-value-no-unknown` rule for the latest CSS specifications. - Fixed: `*-no-unknown` false positives for latest specs by integrating `@csstools/css-syntax-patches-for-csstree` ([#8850](stylelint/stylelint#8850)) ([@romainmenke](https://github.com/romainmenke)). - Fixed: `at-rule-no-unknown` false positives for `@function` ([#8851](stylelint/stylelint#8851)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `declaration-property-value-no-unknown` false positives for `attr()`, `if()` and custom functions ([#8853](stylelint/stylelint#8853)) ([@jeddy3](https://github.com/jeddy3)). - Fixed: `function-url-quotes` false positives when URLs require quoting ([#8804](stylelint/stylelint#8804)) ([@taearls](https://github.com/taearls)). - Fixed: `selector-pseudo-element-no-unknown` false positives for `::scroll-button()` ([#8856](stylelint/stylelint#8856)) ([@Mouvedia](https://github.com/Mouvedia)).

taearls and others added 3 commits October 11, 2025 12:07

taearls changed the title ~~8544/fix/function url quotes false positive~~ fix (Issue #8544): function-url-quotes false positive Oct 11, 2025

taearls mentioned this pull request Oct 11, 2025

Fix function-url-quotes false positives when URLs require quoting #8544

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romainmenke reviewed Oct 11, 2025

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romainmenke changed the title ~~fix (Issue #8544): function-url-quotes false positive~~ Fix function-url-quotes false positives when URLs require quoting Oct 11, 2025

taearls added 4 commits October 11, 2025 13:55

rename function to requiresQuotes

59836a1

run npm build

6de588a

regenerate CJS version of file

5ab2949

update JSDoc comment for requiresQuotes function

3f2ffcf

taearls requested a review from romainmenke October 18, 2025 09:13

romainmenke reviewed Oct 21, 2025

View reviewed changes

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taearls added 5 commits October 21, 2025 14:41

remove list in comment

8aa2000

remove hasQuotes argument from requiresQuotes function

80d019c

regenerate CJS version of file

d4538af

add test cases in response to PR comment, refactor to get them to pass

a45c5ce

use length check of 2 to account for EOF, leave descriptive comment

cc41d83

taearls requested a review from romainmenke October 21, 2025 20:47

romainmenke and others added 3 commits November 26, 2025 18:50

Create rich-ties-lay.md

59b3ec6

Merge branch 'main' into 8544/fix/function-url-quotes-false-positive

00bfa54

format

237614f

romainmenke approved these changes Nov 26, 2025

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jeddy3 approved these changes Nov 27, 2025

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jeddy3 merged commit 4b9c68b into stylelint:main Nov 27, 2025
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Fix `function-url-quotes` false positives when URLs require quoting #8804

Fix `function-url-quotes` false positives when URLs require quoting #8804

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Fix function-url-quotes false positives when URLs require quoting #8804

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Fix `function-url-quotes` false positives when URLs require quoting #8804

Fix `function-url-quotes` false positives when URLs require quoting #8804

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