[ iOS Sim ] REGRESSION (r242277) Layout Test http/tests/cookies/same-site/lax-samesite-cookie-after-cross-site-history-load.php is a flaky timeout

• Component: Tools / Tests
• Status: RESOLVED FIXED

[Shawn Roberts]

The following layout test a timeout on iOS Simulator

http/tests/cookies/same-site/lax-samesite-cookie-after-cross-site-history-load.php

Probable cause:

Test will timeout when it runs after any layout test in the http/tests/cookies/same-site/* directory
Then pass on the re-try
Prior to r242277 this test case is passing

Reproduced with:

run-webkit-tests http/tests/cookies/same-site/ --child-processes 1 --ios-simulator

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fcookies%2Fsame-site%2Flax-samesite-cookie-after-cross-site-history-load.php

[Radar WebKit Bug Importer]

<rdar://problem/48682403>

[Shawn Roberts]

Additional repro steps:

Test first showed on the dashboard for iOS Sim / iOS Debug around r242280

Was unable to reproduce locally running just the test by itself using: 

run-webkit-tests http/tests/cookies/same-site/lax-samesite-cookie-after-cross-site-history-load.php --iterations 500 - f --ios-simulator

Looked at build log for Apple iOS 12 Simulator Release WK2 (Tests) Build #3027 and pulled the worker test list that included this test using Layout test failure analysis website.

Created a test list file from this worker list, and found test failed when running with this test list, then through bisection removed tests preceding this test until I found when running any test in the "http/tests/cookies/same-site/" caused this test to fail.

Searched on trac and found the test change to this test was r241070 and used this as a bisecting point. 

Tested with the following revisions using this command "run-webkit-tests http/tests/cookies/same-site/ --child-processes 1 --ios-simulator"

242623 Timeout
242435 Timeout
242336 Timeout
242285 Timeout
242280 Timeout
242277 Timeout

242276 Passed
242275 Passed
242260 Passed
242234 Passed
241847 Passed
241070 Passed

[Chris Dumez]

Seems very unlikely http://trac.webkit.org/changeset/242277/webkit is the cause but ok.

[Chris Dumez]

Seems to reproduce like so:
run-webkit-tests LayoutTests/http/tests/cookies/same-site/fetch-in-same-origin-worker.html LayoutTests/http/tests/cookies/same-site/lax-samesite-cookie-after-cross-site-history-load.php --child-processes 1 --ios-simulator --no-build

[Chris Dumez]

Created attachment 366097 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 366097 [details]
Patch

Clearing flags on attachment: 366097

Committed r243562: <https://trac.webkit.org/changeset/243562>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.