Bug 230857

Summary: [ iOS 14 & 15 ] fast/images/image-subsampling.html is a flaky image failure
Product: WebKit Reporter: ayumi_kojima
Component: ImagesAssignee: Nobody <webkit-unassigned>
Status: RESOLVED CONFIGURATION CHANGED    
Severity: Normal CC: ap, bfulgham, hhjalmarsson, koivisto, sabouhallawa, simon.fraser, webkit-bot-watchers-bugzilla, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: iPhone / iPad   
OS: Unspecified   
Attachments:
Description Flags
Image diff none

Description ayumi_kojima 2021-09-27 13:58:04 PDT 
fast/images/image-subsampling.html

Is a flaky image failure on iOS (both iOS 14 and iOS 15). The test failure is mainly seen on Release, but it also seen on Debug.

History: https://results.webkit.org/?suite=layout-tests&test=fast%2Fimages%2Fimage-subsampling.html

Result page: https://build.webkit.org/results/Apple-iOS-14-Simulator-Release-WK2-Tests/r283111%20(3394)/results.html
Comment 1 Radar WebKit Bug Importer 2021-09-27 13:58:32 PDT 
<rdar://problem/83589989>
Comment 2 ayumi_kojima 2021-09-27 13:59:26 PDT 
Created attachment 439394 [details]
Image diff
Comment 3 ayumi_kojima 2021-09-27 14:07:42 PDT 
Marked test expectations: https://trac.webkit.org/changeset/283133/webkit
Comment 4 ayumi_kojima 2021-09-29 12:06:54 PDT 
I was not able to reproduce the image failure locally on iOS 14 simulator using run-webkit-tests --force --ios-simulator --iterations 100 --exit-after-n-failures 1 fast/images/image-subsampling.html. 

(The revision I tested was r281967. The failure has been seen for a while according to the history, so I should be able to reproduce with that revision if it was reproducible.)
Comment 5 Alexey Proskuryakov 2021-09-29 14:56:35 PDT 
Actual image is missing the red square.

This seems almost impossible. Why would these work

ctx.fillStyle = "green"
ctx.fillStyle = "blue"

and ctx.fillStyle = "red" right before them not work?
Comment 6 Brent Fulgham 2022-06-23 14:26:10 PDT 
Alexey confirmed this is no longer happening as of 5/25/2022.
Comment 7 EWS 2022-07-01 12:08:54 PDT 
Test gardening commit 252059@main (d26049d74aa8): <https://commits.webkit.org/252059@main>

Reviewed commits have been landed. Closing PR #2003 and removing active labels.
Comment 8 Hercules Hjalmarsson 2022-07-01 12:09:36 PDT 
(In reply to EWS from comment #7)
> Test gardening commit 252059@main (d26049d74aa8):
> <https://commits.webkit.org/252059@main>
> 
> Reviewed commits have been landed. Closing PR #2003 and removing active
> labels.

Removed iOS expectations in above commit.