Bug 237095 – [ Mac EWS ] imported/w3c/web-platform-tests/workers/semantics/multiple-workers/004.html is a flaky text failure

• Status: RESOLVED
• Resolution: FIXED
• Component: Service Workers

[Robert Jenner]

imported/w3c/web-platform-tests/workers/semantics/multiple-workers/004.html

is a flaky text failure on macOS, and is affecting EWS as well.

HISTORY:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fworkers%2Fsemantics%2Fmultiple-workers%2F004.html&platform=mac

LINK TO EWS FAILURE:
https://ews-build.webkit.org/#/builders/60/builds/24663

TEXT DIFF:
-PASS shared worker with multiple documents
+Harness Error (TIMEOUT), message = null
 
+NOTRUN shared worker with multiple documents
+

DIFF URL:
https://build.webkit.org/results/Apple-BigSur-Release-AppleSilicon-WK2-Tests/r290366%20(6732)/imported/w3c/web-platform-tests/workers/semantics/multiple-workers/004-pretty-diff.html

[Radar WebKit Bug Importer]

<rdar://problem/89367636>

[Robert Jenner]

Added [ Pass Failure ] expectation here to speed up EWS:

https://trac.webkit.org/changeset/290386/webkit

[Robert Jenner]

I did attempt to reproduce this failure at Monterey Production ToT. However, I was unsuccessful. I even took it all the way up to 1000 iterations.

[Chris Dumez]

I added some logging in <https://commits.webkit.org/r290439> to help investigate via the bots since I wasn't able to reproduce locally yet.

[youenn fablet]

Added logging shows the following:
CONSOLE MESSAGE: Error: assert_equals: Worker Message Count expected 3 but got 0

Iframes are being loaded but one of the following hypothesis is probably true:
- shared worker might not being executed
- shared worker might not be receiving the connect event
- MessagePort postMessage sometimes does not work

[youenn fablet]

One possibility is that we delay the connect event until we have a process to run the shared worker.
We then fire the connect event for all SharedWorker but we do not respect the order so the first port is related to the iframe SharedWorker instead of the main frame SharedWorker.

[youenn fablet]

Pull request: https://github.com/WebKit/WebKit/pull/1684

[EWS]

Committed r295776 (251781@main): <https://commits.webkit.org/251781@main>

Reviewed commits have been landed. Closing PR #1684 and removing active labels.

[Simon Fraser (smfr)]

This test is crashing in EWS:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fworkers%2Fshared-worker-parse-error-failure.html
https://ews-build.s3-us-west-2.amazonaws.com/macOS-AppleSilicon-Big-Sur-Debug-WK2-Tests-EWS/e9afac16-33487/results.html

[youenn fablet]

Added test is also flaky (fix available at https://bugs.webkit.org/show_bug.cgi?id=241957).
Given I will not be able to fix it very soon, let's revert this change for now in https://bugs.webkit.org/show_bug.cgi?id=241958.

[youenn fablet]

Reopening to fix the debug assertion and flaky test

[youenn fablet]

*** Bug 241957 has been marked as a duplicate of this bug. ***

[youenn fablet]

Pull request: https://github.com/WebKit/WebKit/pull/2054

[EWS]

Committed 252267@main (82a9cba78565): <https://commits.webkit.org/252267@main>

Reviewed commits have been landed. Closing PR #2054 and removing active labels.