Css fix charset at rule#20831
Merged
alexander-akait merged 3 commits intomainfrom Apr 14, 2026
Merged
Conversation
🦋 Changeset detectedLatest commit: 0dc1659 The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
Not sure what this means? Click here to learn what changesets are. Click here if you're a maintainer who wants to add another changeset to this PR |
Contributor
|
This PR is packaged and the instant preview is available (8c7700b). Install it locally:
npm i -D webpack@https://pkg.pr.new/webpack@8c7700b
yarn add -D webpack@https://pkg.pr.new/webpack@8c7700b
pnpm add -D webpack@https://pkg.pr.new/webpack@8c7700b |
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #20831 +/- ##
==========================================
+ Coverage 91.40% 91.44% +0.04%
==========================================
Files 561 562 +1
Lines 55364 55438 +74
Branches 14604 14636 +32
==========================================
+ Hits 50605 50695 +90
+ Misses 4759 4743 -16
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
Contributor
There was a problem hiding this comment.
Pull request overview
This PR adds first-class handling of CSS @charset at-rules within webpack’s CSS module pipeline, ensuring a single normalized @charset is emitted at the correct position and warning on conflicts between modules in the same chunk.
Changes:
- Parse
@charsetinCssParser, storing the detected charset inmodule.buildInfoand removing in-module occurrences (non-styleexportType). - Emit a single
@charsetheader at the beginning of rendered CSS chunks and warn when charsets conflict across modules in a chunk. - Add a dedicated
css/charsetconfig case + snapshot updates; extend typing/docs for the newbuildInfo.charsetfield.
Reviewed changes
Copilot reviewed 27 out of 28 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
lib/css/CssParser.js |
Adds parsing/removal of @charset and stores normalized charset in buildInfo. |
lib/css/CssModulesPlugin.js |
Detects conflicting charsets (warnings) and prepends a single @charset to chunk CSS output. |
lib/css/CssGenerator.js |
Prepends @charset for css-style-sheet exportType output where applicable. |
lib/Module.js |
Documents buildInfo.charset in JSDoc. |
types.d.ts |
Adds charset?: string to build info typing. |
test/configCases/css/charset/webpack.config.js |
New test case configuration covering multiple exportTypes with @charset. |
test/configCases/css/charset/test.config.js |
Test harness setup for loading emitted CSS in the browser-like environment. |
test/configCases/css/charset/warnings.js |
Asserts warning output for conflicting @charset values. |
test/configCases/css/charset/index.js |
New runtime assertions/snapshots for link/text/style/css-style-sheet outputs. |
test/configCases/css/charset/styles-1.link.css |
Fixture: UTF-8 charset + imports. |
test/configCases/css/charset/styles-2.link.css |
Fixture: utf-8 charset variant for normalization test. |
test/configCases/css/charset/styles-3.link.css |
Fixture: conflicting/unknown charset to trigger warning. |
test/configCases/css/charset/styles-4.text.css |
Fixture: text exportType with charset + imports. |
test/configCases/css/charset/styles-5.css-style-sheet.css |
Fixture: css-style-sheet exportType with charset + imports. |
test/configCases/css/charset/styles-6.style.css |
Fixture: style exportType with charset + import. |
test/configCases/css/charset/import.link.css |
Fixture: imported link CSS with charset. |
test/configCases/css/charset/import.text.css |
Fixture: imported text CSS with charset + nested imports. |
test/configCases/css/charset/import-nested.text.css |
Fixture: nested import text CSS with charset. |
test/configCases/css/charset/__snapshots__/ConfigTest.snap |
Adds snapshots for the new css/charset config case. |
test/configCases/css/charset/__snapshots__/ConfigCacheTest.snap |
Cache-mode snapshots for the new css/charset config case. |
test/configCases/css/mini-css-extract-plugin/__snapshots__/ConfigTest.snap |
Updates expected output to a single hoisted @charset. |
test/configCases/css/mini-css-extract-plugin/__snapshots__/ConfigCacheTest.snap |
Cache-mode snapshot updates for hoisted @charset. |
test/configCases/css/css-modules/style.module.css |
Fixture changes (class rename + additional declarations) impacting snapshots. |
test/configCases/css/css-modules/__snapshots__/ConfigTest.snap |
Snapshot updates reflecting CSS modules fixture changes. |
test/configCases/css/css-modules/__snapshots__/ConfigCacheTest.snap |
Cache-mode snapshot updates reflecting fixture changes. |
test/configCases/css/pure-css/__snapshots__/ConfigTest.snap |
Snapshot updates reflecting fixture changes. |
test/configCases/css/pure-css/__snapshots__/ConfigCacheTest.snap |
Cache-mode snapshot updates reflecting fixture changes. |
.changeset/spicy-buckets-fetch.md |
Declares a patch release note for @charset handling. |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Merging this PR will degrade performance by 45.17%
Performance Changes
Comparing 
|
Contributor
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
fix - handle
@charsetat-rulesWhat kind of change does this PR introduce?
fix
Did you add tests for your changes?
Yes
Does this PR introduce a breaking change?
No
If relevant, what needs to be documented once your changes are merged or what have you already documented?
Nothing
Use of AI
No