Bug 193107

Summary: [ Mojave WK1 ] Layout Test fast/layers/blank-content-when-child-layer-is-at-negative-big-number.html and fast/layers/wrong-clipping-semi-transparent-compositing-layer-on-subpixel-position.html are flaky
Product: WebKit Reporter: Truitt Savell <tsavell>
Component: Tools / TestsAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: ap, jlewis3, lforschler, ryanhaddad, simon.fraser
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=193108

Description Truitt Savell 2019-01-03 08:42:51 PST
The following layout tests are flaky on Mojave WK1

fast/layers/blank-content-when-child-layer-is-at-negative-big-number.html
fast/layers/wrong-clipping-semi-transparent-compositing-layer-on-subpixel-position.html

Probable cause:

These two tests are failing in tandem. They seem to be drawing something and unexpectedly zooming in on the result. similar to https://bugs.webkit.org/show_bug.cgi?id=192881 and https://bugs.webkit.org/show_bug.cgi?id=193091

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=fast%2Flayers%2Fblank-content-when-child-layer-is-at-negative-big-number.html%20fast%2Flayers%2Fwrong-clipping-semi-transparent-compositing-layer-on-subpixel-position.html

Image diffs:

fast/layers/blank-content-when-child-layer-is-at-negative-big-number.html
https://build.webkit.org/results/Apple%20Mojave%20Release%20WK1%20(Tests)/r239589%20(1907)/fast/layers/blank-content-when-child-layer-is-at-negative-big-number-diffs.html

fast/layers/wrong-clipping-semi-transparent-compositing-layer-on-subpixel-position.html
https://build.webkit.org/results/Apple%20Mojave%20Release%20WK1%20(Tests)/r239589%20(1907)/fast/layers/wrong-clipping-semi-transparent-compositing-layer-on-subpixel-position-diffs.html
Comment 1 Simon Fraser (smfr) 2019-01-04 11:15:12 PST
Mojave WK1 is basically a world of hurt.