[Eugene (OEvgeny)]

Makes hashed CSS Modules class names reproducible, split from the CSS module theme context PR.

Changelog Entry

Changed

• Hashed CSS class names no longer depend on the build machine's checkout path, in PR #5985, by @OEvgeny

Description

Lightning CSS hashes CSS Modules class names from the absolute file path, so w<hash>_bubble differs between checkouts. It now hashes the path relative to the repository root. Hashed names change once (.wYVITZq_bubble in 4.19 becomes .wbz_wdW_bubble), and readable names such as .bubble stay the same.

Design

• Repository root instead of each package's root, so modules at the same path in different packages still get different hashes.

Specific Changes

• esbuildPlugins.mjs: projectRoot for unplugin-lightningcss

• I have added tests and executed them locally
• I have added .changelog/<PR#>-<slug>.md
• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

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