parcel-bundler / parcel-bundler/lightningcss

Nested selectors should not be transpiled when the parent selector contains pseudo elements.

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#982 0 comments 2 reactions 0 assignees View on GitHub

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Dominant language
Rust
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Description

Good catch!

I've updated the example to avoid the entire :hover::after vs. ::after:hover.

Input:

#b::after {
  & {
     /* nested selectors do not work */
    color: green;
  }
}

LightningCSS outputs:

#b:after {
  color: green;
}

#b:after is incorrect in this case.

Originally posted by @romainmenke in #975

Only nested conditional rules can be transpiled:

div::before {
  @media screen { /* this is fine */ }
}

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported CSS input and comparing LightningCSS's output with the expected selector behavior. Trace the CSS nesting and selector-transpilation path; done means nested selectors under a parent pseudo-element are handled correctly while nested conditional rules such as @media remain transpiled.

Written by the indexing model from the issue text.

Assessment

Tech stack
css, rust
Domain
compilers, web-dev
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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