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minorInvestigatingBunv1.4.4+38afee6c8

Bun CSS @supports At-Rule Parser Fails on Valid Syntax

  1. Investigating(current)
  2. Trending(upcoming)
  3. Workaround available(upcoming)
  4. Resolved(upcoming)

Executive summary

Bun 1.4.4+38afee6c8 fails to bundle valid CSS containing the `@supports (content: counter(line) / '') {}` at-rule, incorrectly rejecting valid syntax used for detecting alt-text support.

No verified workaround yet

None of the linked reports describe a mitigation. Follow this incident to hear when one appears.

Official fix
Technical root cause

The CSS parser in Bun fails to recognize valid <content-list> / <alt-text> syntax within @supports conditions.

Evidence

1 report · 1 GitHubShow
  1. [1]
    GitHub First report
    CSS: @supports at-rule parser misses valid syntax(opens GitHub issue in a new tab)

    What version of Bun is running? 1.4.4+38afee6c8 What platform is your computer? Linux 7.3.1-1-cachyos x86_64 What steps can reproduce the bug? cd $(mktemp -d) echo "@supports (content: counter(line) / '') {}" > t.css bun build t.css What is the expected behavior? That the file bundles without errors. content: <content-list> / <alt-text> is valid CSS, and using it as an @supports condition is the usual way to detect alt-text support for generated content. What do you see instead? 1 | @supports…

    by DiversenSato 0upvotes 1comments

Timeline

  1. First report on GitHub issue

    CSS: @supports at-rule parser misses valid syntax

    Source