[ iOS Simulator] REGRESSION (r241821) Layout Test platform/ipad/fast/viewport/viewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport.html is a flaky failure on bots

• Component: Tools / Tests
• Status: RESOLVED FIXED

[Shawn Roberts]

The following layout test is flaky on iOS Simulator

platform/ipad/fast/viewport/viewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport.html

Probable cause:

It appears changes made in r241821 are causing this test to fail, when it is run immediately after platform/ipad/fast/viewport/viewport-overriden-by-minimum-effective-width-if-ignore-meta-viewport.html

It will fail immediately after, and then pass on the re-test.

Dashboard shows 100% failure since this revision.

Reproduced locally with :

run-webkit-tests platform/ipad/fast/viewport/viewport-overriden-by-minimum-effective-width-if-ignore-meta-viewport.html platform/ipad/fast/viewport/viewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport.html --ipad-simulator --child-processes 1

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=platform%2Fipad%2Ffast%2Fviewport%2Fviewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport.html

Diff:

--- /Users/shawnroberts/Desktop/builds/ios241822/layout-test-results/platform/ipad/fast/viewport/viewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport-expected.txt
+++ /Users/shawnroberts/Desktop/builds/ios241822/layout-test-results/platform/ipad/fast/viewport/viewport-unchanged-by-minimum-effective-width-if-not-ignore-meta-viewport-actual.txt
@@ -1,17 +1,17 @@
 setMinimumEffectiveWidth(640.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [768, 1004]
+square size: [77, 100]
+zoom scale: 1.00
 
 setMinimumEffectiveWidth(768.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [768, 1004]
+square size: [77, 100]
+zoom scale: 1.00
 
 setMinimumEffectiveWidth(834.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [834, 1090]
+square size: [83, 109]
+zoom scale: 0.92
 
 setMinimumEffectiveWidth(980.00)
 window size: [980, 1281]
@@ -19,23 +19,23 @@
 zoom scale: 0.78
 
 setMinimumEffectiveWidth(1024.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [1024, 1339]
+square size: [102, 134]
+zoom scale: 0.75
 
 setMinimumEffectiveWidth(1112.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [1112, 1454]
+square size: [111, 145]
+zoom scale: 0.69
 
 setMinimumEffectiveWidth(1280.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [1280, 1673]
+square size: [128, 167]
+zoom scale: 0.60
 
 setMinimumEffectiveWidth(1336.00)
-window size: [980, 1281]
-square size: [98, 128]
-zoom scale: 0.78
+window size: [1336, 1747]
+square size: [134, 175]
+zoom scale: 0.57

[Radar WebKit Bug Importer]

<rdar://problem/48622090>

[Shawn Roberts]

Additional repro steps:

Found test was a constant failure on dashboard through its available history on iOS Simulator and Debug starting to appear around r241821

Test would not fail locally when running by itself. Using layout test results from build 2973 for Apple iOS 12 Simulator Release WK2 (Tests), I pulled the worker information and used this to start bisecting tests until I found it will fail when preceded by platform/ipad/fast/viewport/viewport-overriden-by-minimum-effective-width-if-ignore-meta-viewport.html

Searched on Trac and found test was moved to a new iPad directory in r240150 and used this as a bisecting point.

242496 Failed
241913 failed
241837 Failed
241824 Failed
241822 Failed
241821 Failed

241820 Passed
241816 Passed
241790 Passed
241768 Passed
241617 Passed
241323 Passed
240150 Passed

[Chris Dumez]

Created attachment 365616 [details]
Patch

[Chris Dumez]

Comment on attachment 365616 [details]
Patch

Clearing flags on attachment: 365616

Committed r243385: <https://trac.webkit.org/changeset/243385>

[Chris Dumez]

All reviewed patches have been landed.  Closing bug.