Bug 213804 – [ macOS wk2 ] REGRESSION(r263485): fast/scrolling/mac/scroll-snapping-in-progress.html is a flaky failure

• Status: ASSIGNED
• Component: Tools / Tests

[Jacob Uphoff]

fast/scrolling/mac/scroll-snapping-in-progress.html

This test has been a flaky failure on macOS wk2 since it was introduced on r263485.

History:

https://results.webkit.org/?suite=layout-tests&test=fast%2Fscrolling%2Fmac%2Fscroll-snapping-in-progress.html

Diff:

 Sending wheel events
 PASS container.scrollTop > 0 is true
-PASS window.internals.isScrollSnapInProgress(container) is true
+FAIL window.internals.isScrollSnapInProgress(container) should be true. Was false.
 PASS successfullyParsed is true
+Some tests failed.
 
 TEST COMPLETE

[Radar WebKit Bug Importer]

<rdar://problem/64948258>

[Simon Fraser (smfr)]

I can reproduce.

[Simon Fraser (smfr)]

Doesn't reproduce when I turn on logging.

[Simon Fraser (smfr)]

When it flakes, we send the scroll event earlier, so we haven't started the scroll snap timer in ScrollController yet.

[Simon Fraser (smfr)]

Seem to relate to whether we handle the two wheel events in the same commit, or different commits.

[Simon Fraser (smfr)]

I don't see a way to make a non-flakey version of this test with the APIs we have. I can't wait for scrolling completion, because scroll snap is something that delays completion. I can't control when scroll events fire relative to wheel events, and I can't use wheel handlers in the test because that sends us down the slow-scrolling path.

[Hector Lopez]

Created attachment 404448 [details]
Patch

[Truitt Savell]

Comment on attachment 404448 [details]
Patch

Clearing flags on attachment: 404448

Committed r264460: <https://trac.webkit.org/changeset/264460>