Bug 211149

Summary:	[ Mac wk2 ] (r259872) scrollingcoordinator/mac/latching/horizontal-overflow-in-vertical-overflow.html is a flaky failure
Product:	WebKit	Reporter:	Truitt Savell <tsavell>
Component:	Scrolling	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	simon.fraser, webkit-bot-watchers-bugzilla, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Truitt Savell 2020-04-28 15:24:46 PDT

scrollingcoordinator/mac/latching/horizontal-overflow-in-vertical-overflow.html

This test is a rare flaky failure on Mac wk2

History
https://results.webkit.org/?suite=layout-tests&test=scrollingcoordinator%2Fmac%2Flatching%2Fhorizontal-overflow-in-vertical-overflow.html&limit=50000

Diff
--- /Volumes/Data/slave/mojave-release-tests-wk2/build/layout-test-results/scrollingcoordinator/mac/latching/horizontal-overflow-in-vertical-overflow-expected.txt
+++ /Volumes/Data/slave/mojave-release-tests-wk2/build/layout-test-results/scrollingcoordinator/mac/latching/horizontal-overflow-in-vertical-overflow-actual.txt
@@ -4,7 +4,7 @@
 PASS outerScroller.scrollTop is 0
 PASS innerScroller.scrollTop is 0
 After scrolll
-PASS outerScroller.scrollTop is 200
+FAIL outerScroller.scrollTop should be 200. Was 100.
 PASS innerScroller.scrollTop is 0
 PASS successfullyParsed is true
 

Reproduced with:
run-webkit-tests --iterations 2000 --exit-after-n-failures 1 --exit-after-n-crashes-or-timeouts 1 --debug-rwt-logging --no-retry --force --no-build -f scrollingcoordinator/mac/latching/horizontal-overflow-in-vertical-overflow.html

Comment 1 Radar WebKit Bug Importer 2020-04-28 15:25:15 PDT

<rdar://problem/62550691>

Comment 2 Truitt Savell 2020-04-28 15:25:37 PDT

This test was introduced in https://trac.webkit.org/changeset/259872/webkit

Comment 3 Simon Fraser (smfr) 2020-04-28 20:12:14 PDT

100 vs 200 means we got one fewer wheel events, probably because they got coalesced.