RESOLVED FIXED 196985
REGRESSION: (r244182) Layout Test editing/execCommand/insert-nested-lists.html is flaky 
https://bugs.webkit.org/show_bug.cgi?id=196985
Summary REGRESSION: (r244182) Layout Test editing/execCommand/insert-nested-lists.htm...
Truitt Savell
Reported 2019-04-16 14:25:51 PDT
The following layout test is flaky on Mac Release WK2 editing/execCommand/insert-nested-lists.html Probable cause: This test became flakey with https://trac.webkit.org/changeset/244182/webkit I reproduced this issue with command: run-webkit-tests editing/execCommand/insert-nested-lists.html --iterations 500 -f The test fails randomly on 244182 and passes fully on 244181. Flakiness Dashboard: https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=editing%2FexecCommand%2Finsert-nested-lists.html Diff: --- /Volumes/Data/slave/mojave-release-tests-wk2/build/layout-test-results/editing/execCommand/insert-nested-lists-expected.txt +++ /Volumes/Data/slave/mojave-release-tests-wk2/build/layout-test-results/editing/execCommand/insert-nested-lists-actual.txt @@ -43,52 +43,39 @@ | <br> | <ol> | <li> -| "bar" -| <ul> -| <li> -| <#selection-caret> +| <#selection-caret> After selecting a range and inserting another unordered list: | <ul> | <li> | "foo" | <br> -| <ol> +| <ul> | <li> -| "bar" -| <ul> +| <#selection-caret> +| <ol> | <li> -| <#selection-caret> -| <ul> -| <li> After outdenting: | <ul> | <li> | "foo" | <br> -| <ol> -| <li> -| "bar" -| <li> -| <#selection-caret> -| <br> -| <ul> -| <ul> -| <li> +| <li> +| <#selection-caret> +| <br> +| <ul> +| <ol> +| <li> After outdenting again: | <ul> | <li> | "foo" | <br> -| <ol> -| <li> -| "bar" -| <li> -| "baz<#selection-caret>" -| <br> -| <ol> -| <ul> -| <ul> -| <li> +| "baz<#selection-caret>" +| <br> +| <ul> +| <ul> +| <ol> +| <li>
Attachments
Fixes the test (1.82 KB, patch)
2019-04-19 12:31 PDT, Ryosuke Niwa 		wenson_hsieh: review+
DetailsFormatted DiffDiff
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Radar WebKit Bug Importer
Comment 1 2019-04-16 14:27:22 PDT
<rdar://problem/49954111>
Alexey Proskuryakov
Comment 2 2019-04-18 10:02:55 PDT
This is a bit surprising. This test doesn't use rAF, and generally looks like it should be deterministic. Said, Wenson, any ideas on how the regression could happen here?
Wenson Hsieh
Comment 3 2019-04-18 10:04:47 PDT
(In reply to Alexey Proskuryakov from comment #2) > This is a bit surprising. This test doesn't use rAF, and generally looks > like it should be deterministic. > > Said, Wenson, any ideas on how the regression could happen here? It actually does use requestAnimationFrame: await new Promise(resolve => requestAnimationFrame(resolve));
Shawn Roberts
Comment 4 2019-04-18 11:27:45 PDT
Found another editing test regressed by r244182. Linking to 197065
Ryosuke Niwa
Comment 5 2019-04-19 12:25:33 PDT
There is no reason to believe that waiting for rAF would cause UI process' runloop to run. So we need to be making an explicit round trip to UI process instead.
Ryosuke Niwa
Comment 6 2019-04-19 12:31:12 PDT
Created attachment 367811 [details] Fixes the test
Ryosuke Niwa
Comment 7 2019-04-19 12:33:25 PDT
Committed r244461: <https://trac.webkit.org/changeset/244461>
Ryosuke Niwa
Comment 8 2019-04-22 19:39:26 PDT
Looks like the flakiness is gone!
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