Bug 225282 – Invalid media query keyword values should not be parsable

• Component: CSS
• Status: RESOLVED FIXED

[Tim Nguyen (:ntim)]

Examples:

prefers-color-scheme: none
prefers-color-scheme: aghadshudfsjhdsfkjhdsfdsfa
prefers-color-scheme: visible
prefers-color-scheme: hidden
prefers-color-scheme: -webkit-sticky
prefers-color-scheme: cssisawesome

Ditto for prefers-contrast

WebKit all considers them as parsable... 

This shows up in our WPT failures (notably the none cases for prefers-contrast/prefers-color-scheme).

Example snippet to reproduce:

function query_is_css_parseable(query) {
  const style = document.createElement('style');
  style.type = 'text/css';
  document.head.appendChild(style);

  const sheet = style.sheet;
  try {
    sheet.insertRule("@media " + query + "{}", 0);
    return sheet.cssRules.length == 1 &&
        sheet.cssRules[0].media.mediaText != "not all";
  } finally {
    while (sheet.cssRules.length)
      sheet.deleteRule(0);
    style.remove();
  }
}

query_is_css_parseable("(prefers-color-scheme: -webkit-sticky)") // should return false

[Tim Nguyen (:ntim)]

Created attachment 427783 [details]
Patch

[Radar WebKit Bug Importer]

<rdar://problem/77566627>

[Dean Jackson]

In the future we might want to do this with generated code, the way we do with properties.

[Tim Nguyen (:ntim)]

Committed r277039 (237352@main): <https://commits.webkit.org/237352@main>