Evaluate the media query list in matchMedia against the render device - #228
Merged
Merged
Conversation
CssMediaQueryList.ComputeMatched returned a constant false, so window.matchMedia(...).IsMatched answered false for every query, including "all" and the empty query, which always match. It now validates the media list against the render device from the browsing context, reusing the very same evaluation that @media rules already go through for the cascade, and falls back to DefaultRenderDevice when no device is registered - the same fallback GetComputedStyle uses. Reported in AngleSharp/AngleSharp#1307. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NqCcJrL3MJecCPRBMQsZyC
This was referenced Sep 2, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
CssMediaQueryList.ComputeMatchedreturned a constantfalse, sowindow.matchMedia(...).IsMatchedansweredfalsefor every query - evenalland the empty query, which always match; this was reported in AngleSharp/AngleSharp#1307. It now validates the media list against the browsing context'sIRenderDevicethrough the sameMediaListExtensions.Validatepath that@mediarules already take for the cascade, falling back toDefaultRenderDevicewhen no device is registered, exactly asGetComputedStyledoes. Tests cover media types,min-width/max-width/min-height,and,only,not, an unknown feature and the empty query, per https://drafts.csswg.org/mediaqueries-4/#mq-list and https://drafts.csswg.org/cssom-view/#dom-window-matchmedia.