Bug 250885 – [ iOS arm64 ] css3/filters/effect-contrast-hw.html is a constant image failure

• Status: NEW
• Component: CSS

[Bri Harris]

css3/filters/effect-contrast-hw.html

is a constant image only failure on iOS 16 release running on Apple Silicon only. 

HISTORY: 
https://results.webkit.org/?suite=layout-tests&test=css3%2Ffilters%2Feffect-contrast-hw.html&architecture=arm64

IMAGE DIFF URL: 
https://build.webkit.org/results/Apple-iOS-16-Simulator-Release-arm64-WK2-Tests/259102@main%20(754)/css3/filters/effect-contrast-hw-diffs.html

image diff images attached to bug.

[Bri Harris]

Created attachment 464571 [details]
Image Diffs for Failing Test

[Bri Harris]

I was able to reproduce this failure on my Apple Silicon Mac at iOS 16 Release ToT running the test as follows:

Run-Webkit-Tests css3/filters/effect-contrast-hw.html

Scrolling backwards in the history, it appears this test has been a constant image failure since we started running testing on iOS 16.

[Radar WebKit Bug Importer]

<rdar://problem/104456051>

[Alexey Proskuryakov]

This is a curious diff - it's not the colors that are different, but box sizes! Are contrast filters doing the wrong thing at the edges?

[Simon Fraser (smfr)]

It's possible the CoreAnimation's contrast filter has slightly different behavior. But I think it's OK to just increase the pixel tolerance here.

[Alexey Proskuryakov]

Hmm, isn't this going to create user visible cracks in page layout when this filter is used?

[Bri Harris]

Pull request: https://github.com/WebKit/WebKit/pull/8897

[EWS]

Test gardening commit 259154@main (9770e5c864b4): <https://commits.webkit.org/259154@main>

Reviewed commits have been landed. Closing PR #8897 and removing active labels.

[Bri Harris]

It appears that this test has been a constant image only failure on iOS 16 simulator running only on an Apple Silicon machine since this test was introduced at :

https://commits.webkit.org/254408@main

[Dawn Morningstar]

This is happening on Debug as well, not just Release

[Dawn Morningstar]

Pull request: https://github.com/WebKit/WebKit/pull/32415

[EWS]

Test gardening commit 282459@main (8d65c4020a14): <https://commits.webkit.org/282459@main>

Reviewed commits have been landed. Closing PR #32415 and removing active labels.