Layout Test imported/w3c/web-platform-tests/service-workers/service-worker/claim-with-redirect.https.html is flaky

[Ryan Haddad]

The following layout test is flaky on macOS Debug WK2

imported/w3c/web-platform-tests/service-workers/service-worker/claim-with-redirect.https.html

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=imported%2Fw3c%2Fweb-platform-tests%2Fservice-workers%2Fservice-worker%2Fclaim-with-redirect.https.html

--- /Volumes/Data/slave/elcapitan-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/service-workers/service-worker/claim-with-redirect.https-expected.txt
+++ /Volumes/Data/slave/elcapitan-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/service-workers/service-worker/claim-with-redirect.https-actual.txt
@@ -1,4 +1,4 @@
-CONSOLE MESSAGE: line 27: Unhandled Promise Rejection: TypeError: undefined is not an object (evaluating 'r.update')
+CONSOLE MESSAGE: Unhandled Promise Rejection: TypeError: Cannot update a null/nonexistent service worker registration
   
 
 FAIL Claim works after redirection to another origin assert_equals: expected (string) "updated" but got (undefined) undefined

[Ryan Haddad]

This test recently became flaky.

[Ryan Haddad]

This is related to https://trac.webkit.org/changeset/225346/webkit

[Alexey Proskuryakov]

I remember that we made improvements to generating line numbers in console messages more reliably a couple years ago, but I guess there are still edge cases?

[Joseph Pecoraro]

This unhandled promise rejection gets line numbers from Exceptions. Here it looks like the exception itself is changing so apparently the new exception doesn't have line number information associated with it.

[youenn fablet]

claim is not supported yet.
Hopefully, when it gets implemented, flakiness might disappear.

We could use DumpConsoleLogInStdErr to make the test stable but this is probably not worth it right now.