Bug 217114 – REGRESSION: [ iOS release wk2 ] compositing/debug-borders-dynamic.html is a flaky image failure

• Component: Compositing
• Status: RESOLVED FIXED

[Karl Rackler]

Description:
compositing/debug-borders-dynamic.html

The first image failure that I see this on the dashboard was 09/29/20 at r267758, but does not appear to be relevant to what would have caused this.
There is only one day of test history with this being the only image failure on the dashboard so far.

The test was expecting to repaint 2px solid red border with transform, but seems to have returned without transform.

History:
https://results.webkit.org/?suite=layout-tests&test=compositing%2Fdebug-borders-dynamic.html&limit=50000&version_name=iOS%2014

Diff:
https://build.webkit.org/results/Apple-iOS-14-Simulator-Release-WK2-Tests/r267758%20(20)/compositing/debug-borders-dynamic-diffs.html

[Radar WebKit Bug Importer]

<rdar://problem/69772621>

[Karl Rackler]

I have marked this test as image failure while this issue is investigated.
https://trac.webkit.org/changeset/267776/webkit

[Karl Rackler]

REPRODUCTION STEPS
Build 17H35:
I can reproduce this image failure with most recent available spade r267194.

Build 18A393:
I can reproduce this image failure on all spades tried between r262500 and ToT 267802.  The test will usually fail within the first 50 to 100 iterations.  Because the test was consistent in failures, I cannot pinpoint a change that could have caused this.

Command: 
run-webkit-tests --ios-simulator --iterations 2000 --exit-after-n-failures 1 --exit-after-n-crashes-or-timeouts 1 --debug-rwt-logging --no-retry --force --no-build -f compositing/debug-borders-dynamic.html

Result: 
Regressions: Unexpected image-only failures (1)
  compositing/debug-borders-dynamic.html [ ImageOnlyFailure ]

[Dawn Morningstar]

compositing/debug-borders-dynamic.html 
Is still a flaky failure on iOS Debug queue, as an expectation has not been set.

[Simon Fraser (smfr)]

This should be solved with pixel tolerance (it's some pixel fuzz around the repaint counter).

[Karl Rackler]

Pull request: https://github.com/WebKit/WebKit/pull/15124

[Karl Rackler]

Adjusting pixel tolerance for the following test:
compositing/debug-borders-dynamic.html

[EWS]

Committed 265343@main (98fc2d9d56ca): <https://commits.webkit.org/265343@main>

Reviewed commits have been landed. Closing PR #15124 and removing active labels.

[Karl Rackler]

Adjusting pixel tolerance for the following test:
compositing/debug-borders-dynamic.html

[Karl Rackler]

Re-opening for pull request https://github.com/WebKit/WebKit/pull/15145

[EWS]

Committed 265360@main (5512c619b8aa): <https://commits.webkit.org/265360@main>

Reviewed commits have been landed. Closing PR #15145 and removing active labels.

[Karl Rackler]

Remove test expectations

[EWS]

Test gardening commit 265368@main (e6e95e294e70): <https://commits.webkit.org/265368@main>

Reviewed commits have been landed. Closing PR #15154 and removing active labels.