Bug 198661

Summary: Layout Test landed flaky [ Mojave WK2 ] scrollingcoordinator/mac/nested-sticky.html is a flaky ImageOnlyFailure and Timeout
Product: WebKit Reporter: Shawn Roberts <sroberts>
Component: Tools / TestsAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: fred.wang, jlewis3, ryanhaddad, simon.fraser, tsavell, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=197255

Description Shawn Roberts 2019-06-07 09:04:06 PDT
The following layout test is flaky on Mojave WK2 Debug and Release

scrollingcoordinator/mac/nested-sticky.html

Probable cause:

Test is more flaky on Debug runs. Test was added in r244630 and appears to have been flaky its entire available history on the dashboard. 

The ImageOnlyFailure's appear to only happen on Debug runs. Cannot reproduce them on Release builds, but the Release timeout is reproducible just as easily on Release builds.

Reproducible with:

run-webkit-tests scrollingcoordinator/mac/nested-sticky.html --iter 100 -f --debug

Will average aboutt 3 reference mismatches and 4 timeouts be 100 iteration run. 

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=scrollingcoordinator%2Fmac%2Fnested-sticky.html
Comment 1 Radar WebKit Bug Importer 2019-06-07 09:04:47 PDT
<rdar://problem/51523533>
Comment 2 Shawn Roberts 2019-06-07 09:13:19 PDT
Marked flaky in https://trac.webkit.org/changeset/246202/webkit