Avoid relative color syntax in login stylesheet - #306
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Applications that still bundle sassc-rails get Sprockets' SassC css_compressor, which re-parses our already-minified build output as SCSS. libSass resolves hsl() and rgb() to its own builtins and aborts on the relative color form, so precompiling assets fails for those hosts. color-mix() expresses the same 50% alpha and is unknown to libSass, so it passes through untouched while staying valid modern CSS with wider browser support than relative colors.
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #306 +/- ##
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Coverage 98.58% 98.58%
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Hits 279 279
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[8.4-stable] Merge pull request #306 from AlchemyCMS/fix-login-css-relative-color
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Applications that still bundle
sassc-railsfail to precompile assets since we started shipping the login styles as pre-built CSS. Sprockets installs the SassCcss_compressorwhenever that gem is present, and it re-parses our already-minified build output as SCSS. libSass resolveshsl()andrgb()to its own builtins, so the relative color form in.logo-boxaborts the whole precompile withFunction hsl is missing argument $saturation.color-mix(in srgb, ... 50%, transparent)expresses exactly the same 50% alpha —color-mixinterpolates premultiplied, so mixing withtransparentonly touches the alpha channel. libSass has no builtin of that name and passes it through untouched. It is also better supported in browsers than relative colors (Baseline 2023 vs. Safari 16.4 / Firefox 128), so this is not a compatibility regression.Worth noting that this only avoids the one construct that currently trips libSass rather than preventing the class of problem: a future relative color, or even a plain space-separated
hsl(200 50% 50%), would break these hosts again the same way. The structural fix belongs in alchemy_cms, whoseAlchemy::Sprockets::SkipBuildsCompressionalready skips compression for pre-built CSS but hardcodes its own engine root and so never covers this gem'sapp/assets/builds.