1837340 - Firefox fails WPT css/css-masking/clip-path/interpolation.html due to "at 50% 50%" being included in our serialization

Status: RESOLVED DUPLICATE of bug 1823475

(Core :: CSS Transitions and Animations, defect)

Description

[Daniel Holbert [:dholbert]]

WPT css/css-masking/clip-path/interpolation.html changed upstream recently, such that we fail some subtests (though we haven't merged the change into mozilla-central yet, so we still pass our local copy of this WPT test).

wpt.fyi:
https://wpt.fyi/results/css/css-masking/clip-path/interpolation.html

Direct link to test:
http://wpt.live/css/css-masking/clip-path/interpolation.html

The issue seems to be that we're serializing the default at 50% 50% position, and the test now expects that we don't serialize that position in this case, specifically because it wasn't part of the author specified value.

Here's where the test changed:
https://github.com/web-platform-tests/wpt/commit/d438bdbf5bae2a22b574180da57a6bd0f19d12ee

It was in response to this spec issue/comment:
https://github.com/w3c/csswg-drafts/issues/8695#issuecomment-1563497665

Comment 1

[Boris Chiou [:boris]]

I am updating the serialization for at <position> to omit "at 50% 50%" at the parser (for motion) in https://phabricator.services.mozilla.com/D179626. Once we sync with WPT upstream, I will try to fix the serialization for clip-path and shape-outside in this bug.

Comment 2

[Boris Chiou [:boris]]

Attachment: Bug 1837340 - Update the serialization of "at <position>" for basic shapes (wip).

Comment 3

[Phabricator Automation]

Comment on attachment 9340807 [details]
Bug 1837340 - Update the serialization of "at <position>" for basic shapes (wip).

Revision D181918 was moved to bug 1823475. Setting attachment 9340807 [details] to obsolete.

Comment 4

[Boris Chiou [:boris]]

I may fix this together in Bug 1823475.