Bug 231609

Summary: [ iOS15 iPad Debug ] imported/w3c/web-platform-tests/webmessaging/MessagePort_onmessage_start.any.worker.html is a flaky failure (reached unreachable code)
Product: WebKit Reporter: Eric Hutchison <ehutchison>
Component: New BugsAssignee: Chris Dumez <cdumez>
Status: RESOLVED FIXED    
Severity: Normal CC: achristensen, cdumez, clopez, ehutchison, ews-watchlist, ggaren, sam, webkit-bot-watchers-bugzilla, webkit-bug-importer, youennf
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch none

Description Eric Hutchison 2021-10-12 13:46:27 PDT 
imported/w3c/web-platform-tests/webmessaging/MessagePort_onmessage_start.any.worker.html 

is a flaky failure on iOS15 Debug on iPad

History: https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fwebmessaging%2FMessagePort_onmessage_start.any.worker.html

Build: https://build.webkit.org/#/builders/265/builds/63

Results: https://build.webkit.org/results/Apple-iPadOS-15-Simulator-Debug-WK2-Tests/r283979%20(63)/results.html

Diff:
--- /Volumes/Data/worker/ipados-simulator-15-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/webmessaging/MessagePort_onmessage_start.any.worker-expected.txt
+++ /Volumes/Data/worker/ipados-simulator-15-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/webmessaging/MessagePort_onmessage_start.any.worker-actual.txt
@@ -1,3 +1,3 @@
 
-PASS MessageChannel: port.onmessage enables message queue
+FAIL MessageChannel: port.onmessage enables message queue assert_unreached: Reached unreachable code
Comment 1 Radar WebKit Bug Importer 2021-10-12 13:49:25 PDT 
<rdar://problem/84164701>
Comment 2 Eric Hutchison 2021-10-12 13:53:19 PDT 
Updated test expectations at https://trac.webkit.org/changeset/284020/webkit
Comment 3 Chris Dumez 2021-10-19 11:06:38 PDT 
The test has:
setTimeout(t.unreached_func(), 100);

So I think this means that it took more than 100ms for the message event to get dispatched. This is not too surprising that this test would be flaky, especially on slower configuration. The WPT test needs fixing here I believe.
Comment 4 Chris Dumez 2021-10-19 11:11:59 PDT 
Upstream pull request: https://github.com/web-platform-tests/wpt/pull/31317
Comment 5 Chris Dumez 2021-10-21 07:53:57 PDT 
Created attachment 442021 [details]
Patch
Comment 6 EWS Watchlist 2021-10-21 07:55:07 PDT 
This patch modifies the imported WPT tests. Please ensure that any changes on the tests (not coming from a WPT import) are exported to WPT. Please see https://trac.webkit.org/wiki/WPTExportProcess
Comment 7 Chris Dumez 2021-10-22 08:30:01 PDT 
ping review?
Comment 8 EWS 2021-10-22 09:05:28 PDT 
Committed r284686 (243406@main): <https://commits.webkit.org/243406@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 442021 [details].