[bjohansebas]

Summary

The CSS codemod currently leaves css-minimizer-webpack-plugin in place. Migrate supported cssnano default-preset options to optimization.minimizeOptions.css: for example, discardComments: { removeAll: true } becomes comments: false with comment extraction disabled, and colormin: false becomes shortenColors: false.

Keep minimizer recognition and option translation in separate modules, using AST edits and scope resolution. Preserve the build's minimize switch, other asset types, custom minimizers, and compatible native settings. Unsupported or conflicting configurations retain their original plugin and options. The package dependency is retained for remaining uses elsewhere in the project.

Include a patch changeset for @webpack/css-plugins-to-native-css.

What kind of change does this PR introduce?

Fix: extend the CSS migration to preserve supported minifier options.

Did you add tests for your changes?

Yes, 46 fixtures covering CJS/ESM/TypeScript, option translation, existing native options, other asset types, custom minimizers, unsupported configurations, shadowed/reassigned bindings, CRLF, and idempotence.

Validation passed:

• npm test — all 233 tests passed.
• npm run lint and npm run type-check.
• Full workflow in a temporary project: dry run, migration, and repeat-run idempotence, without granting filesystem permissions to the codemod.
• Eight migrated configurations validated against webpack 5.112.2, plus native minifier checks for comments, colors, and longhands.

Does this PR introduce a breaking change?

The new minifier migration targets webpack >= 5.112.0, including its comment extraction controls; projects using this migration must meet that requirement. Existing loader/extraction migrations retain their webpack >= 5.109.0 requirement.

Some native switches group several cssnano passes. Disabling one of those passes disables the native group, which can result in fewer optimizations.

If relevant, what needs to be documented once your changes are merged or what have you already documented?

Updated the codemod README with a before/after example, option mappings, version requirements, unsupported cases, and dependency cleanup guidance. Updated the root README and registry/workflow descriptions.

Use of AI

Codex assisted with inspecting the upstream APIs, implementing the AST migration, adding fixtures and documentation, running the validations above, and drafting this description.

[changeset-bot]

🦋 Changeset detected

Latest commit: 2ec7eef

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

This PR includes changesets to release 1 package

Name	Type
@webpack/css-plugins-to-native-css	Patch

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