Bug 269116 – REGRESSION (273737@main): [ iOS 17 ] imported/w3c/web-platform-tests/css/css-flexbox/negative-overflow-002.html is a consistent text failure

• Component: New Bugs
• Status: CLOSED FIXED

[Jay Stfleur]

Description:
imported/w3c/web-platform-tests/css/css-flexbox/negative-overflow-002.html 

Is a constant text failure 


History:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fcss%2Fcss-flexbox%2Fnegative-overflow-002.html

Diff/Image Diff/Crash Log:
https://ews-build.s3-us-west-2.amazonaws.com/iOS-17-Simulator-WPT-WK2-Tests-EWS/43d8eb76-12932-clean-tree/imported/w3c/web-platform-tests/css/css-flexbox/negative-overflow-002-pretty-diff.html

[Radar WebKit Bug Importer]

<rdar://problem/122678250>

[Jay Stfleur]

Reproducibility:
run-webkit-tests --root --ios-simulator imported/w3c/web-platform-tests/css/css-flexbox/negative-overflow-002.html --child-process=1 --iterations 1

[EWS]

Test gardening commit 274401@main (f3b0aad8b0a5): <https://commits.webkit.org/274401@main>

Reviewed commits have been landed. Closing PR #24186 and removing active labels.

[Simon Fraser (smfr)]

I am still seeing EWS failures with this test:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fcss%2Fcss-flexbox%2Fnegative-overflow-002.html

https://ews-build.webkit.org/#/builders/42/builds/12930

[fantasai]

The regression point matches https://github.com/WebKit/WebKit/pull/23038 which removed the iOS-specific expected file for this test in order to pass EWS before landing. But it seems like now it requires one again. The differences are all 15px, just like in the previous version, and on the same subtests.

I’m not sure why there was ever a 15px difference on iOS on any of the tests, as it doesn’t seem like the sort of test that should have platform differences, and my guess is it has something to do with scrollbars because I’m not sure where else the 15px would come from. The differences only seem to appear in horizontal RTL writing modes, and indeed in these modes the scrollbars are rendered differently in iOS and MacOS.

You can see this if you scroll the 13th box (in row-major order) in the testcase: http://wpt.live/css/css-flexbox/negative-overflow-002.html
1. There’s a gap between the border-box and the scrollbar, this is almost certainly wrong.
2. The scrollbars are on the left, instead of on the right as in iOS.

For #2 it’s not clear what the intention was; it’s definitely odd that it’s inconsistent between OSes.

Tess recommended rebaselining the test and following up in other bugs.

[fantasai]

Pull request: https://github.com/WebKit/WebKit/pull/24905

[fantasai]

Bugs showing up in the testcase, fwiw:
* https://bugs.webkit.org/show_bug.cgi?id=263512
* https://bugs.webkit.org/show_bug.cgi?id=255346

Maybe:
* https://bugs.webkit.org/show_bug.cgi?id=247230

[Simon Fraser (smfr)]

On iOS in layout tests scrollbars are always zero-width, so (annoyingly) iOS results are often different by 15px.

[EWS]

Committed 275526@main (43c839024fcd): <https://commits.webkit.org/275526@main>

Reviewed commits have been landed. Closing PR #24905 and removing active labels.

[Jay Stfleur]

Re-opening for pull request https://github.com/WebKit/WebKit/pull/28063

[EWS]

Test gardening commit 278289@main (113d9483bb8a): <https://commits.webkit.org/278289@main>

Reviewed commits have been landed. Closing PR #28063 and removing active labels.