RESOLVED FIXED 238965
[ iOS EWS ] css3/background/background-repeat-round-auto2.html is a image failure
https://bugs.webkit.org/show_bug.cgi?id=238965
Summary [ iOS EWS ] css3/background/background-repeat-round-auto2.html is a image fai...
Dawn Morningstar
Reported 2022-04-07 15:29:29 PDT
css3/background/background-repeat-round-auto2.html is an image failure on iOS EWS queue. This does not appear on the results database: HISTORY: https://results.webkit.org/?suite=layout-tests&test=css3%2Fbackground%2Fbackground-repeat-round-auto2.html DIFF IMAGES WILL BE ATTACHED. DIFF-URL: https://ews-build.s3-us-west-2.amazonaws.com/iOS-15-Simulator-WK2-Tests-EWS/456887-12620/css3/background/background-repeat-round-auto2-diffs.html
Attachments
BUG238965 DIFFS (89.56 KB, application/zip)
2022-04-07 17:13 PDT, Dawn Morningstar
no flags
retry diff (8.83 KB, image/png)
2022-04-13 11:28 PDT, Alexey Proskuryakov
no flags
first try diff (9.99 KB, image/png)
2022-04-13 11:29 PDT, Alexey Proskuryakov
no flags
ImageDiff tolerance patch (6.52 KB, patch)
2022-04-22 15:29 PDT, Simon Fraser (smfr)
no flags
Patch (7.01 KB, patch)
2022-04-25 12:02 PDT, Simon Fraser (smfr)
thorton: review+
Patch (7.00 KB, patch)
2022-04-25 20:19 PDT, Simon Fraser (smfr)
ews-feeder: commit-queue-
Radar WebKit Bug Importer
Comment 1 2022-04-07 17:11:00 PDT
Dawn Morningstar
Comment 2 2022-04-07 17:13:02 PDT
Alexey Proskuryakov
Comment 3 2022-04-08 16:16:46 PDT
Antialiasing around edges. Probably a preceding test leaving something graphics related in a bad state. Finding a repro case would help see if it's something we can fix.
Dawn Morningstar
Comment 4 2022-04-08 17:53:50 PDT
(In reply to Alexey Proskuryakov from comment #3) > Antialiasing around edges. Probably a preceding test leaving something > graphics related in a bad state. Finding a repro case would help see if it's > something we can fix. I knew it! - You had commented on a previous bug I had made and said it was antialiasing and this appeared to be very similar to that... I'll bisect a test list for this and attempt to reproduce the failure and detect the preceding test.
Alexey Proskuryakov
Comment 5 2022-04-13 11:28:28 PDT
> https://ews-build.s3-us-west-2.amazonaws.com/iOS-15-Simulator-WK2-Tests-EWS/456887-12620/css3/background/background-repeat-round-auto2-diffs.html Build link for this: https://ews-build.webkit.org/#/builders/68/builds/12620 What's interesting is that this is EWS, so failing a test means that it fails as part of the main test suite first, but also fails on retry with --singly, so it's actually not about any preceding tests in the process. In this run, it failed like this first: 11:31:31.809 80268 [1361/53799] css3/background/background-repeat-round-auto2.html failed unexpectedly (reference mismatch maxDifference=1; totalPixels=360) 11:31:31.810 80268 worker/4 css3/background/background-repeat-round-auto2.html failed: 11:31:31.810 80268 worker/4 reference mismatch maxDifference=1; totalPixels=360 And then: 12:30:58.239 80268 [2/14] css3/background/background-repeat-round-auto2.html failed unexpectedly (reference mismatch maxDifference=1; totalPixels=94) 12:30:58.239 80268 css3/background/background-repeat-round-auto2.html failed: 12:30:58.239 80268 reference mismatch maxDifference=1; totalPixels=94 12:30:58.240 80268 finished test group Only some of the circles had antialiasing diffs on retry!
Alexey Proskuryakov
Comment 6 2022-04-13 11:28:58 PDT
Created attachment 457549 [details] retry diff
Alexey Proskuryakov
Comment 7 2022-04-13 11:29:30 PDT
Created attachment 457550 [details] first try diff
Dawn Morningstar
Comment 8 2022-04-22 13:09:30 PDT
css3/background/background-repeat-round-auto1.html Seems to also be an Antialiasing issue, Duping that bug onto this one. https://bugs.webkit.org/show_bug.cgi?id=238781
Dawn Morningstar
Comment 9 2022-04-22 13:09:48 PDT
*** Bug 238781 has been marked as a duplicate of this bug. ***
Simon Fraser (smfr)
Comment 10 2022-04-22 13:53:01 PDT
The various diffs show that that antialiasing differences can be limited to just some CALayers (page tiles).
Simon Fraser (smfr)
Comment 11 2022-04-22 14:40:18 PDT
I think we need to bring back the built-in tolerance of 1 per color component.
Simon Fraser (smfr)
Comment 12 2022-04-22 14:56:20 PDT
This is cause by using different GPU shaders on different layers. These shaders are not expected to be exact, and results can differ by 1 per component. ImageDiff does have built-in tolerance (we don't use --exact), but here three color components are different by 1/255: difference: exact 0 legacyDistance 0.00656 threshold 0.00392 over 1 133 132 133 132 133 132 255 255
Simon Fraser (smfr)
Comment 13 2022-04-22 15:29:42 PDT
Created attachment 458178 [details] ImageDiff tolerance patch
Simon Fraser (smfr)
Comment 14 2022-04-25 12:02:17 PDT
Simon Fraser (smfr)
Comment 15 2022-04-25 20:19:02 PDT
EWS
Comment 16 2022-04-26 14:18:29 PDT
Tools/Scripts/svn-apply failed to apply attachment 458323 [details] to trunk. Please resolve the conflicts and upload a new patch.
Simon Fraser (smfr)
Comment 17 2022-04-26 14:22:54 PDT
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