Bug 286584 – REGRESSION (286180@main): [ macOS wk2 debug ] imported/w3c/web-platform-tests/navigation-api/navigation-methods/return-value/back-204-205-download.html is a flaky failure

• Component: New Bugs
• Status: NEW

[Karl Rackler]

Description:
imported/w3c/web-platform-tests/navigation-api/navigation-methods/return-value/back-204-205-download.html

The flakiness dashboard shows the test regressing between 286190@main...286180@main ( https://commits.webkit.org/compare/286190@main...286180@main ).  286180@main  modifies the test and, therefore, the likely culprit.

This issue can be bisected to 286180@main using the command: 
run-webkit-tests --debug--no-retry --force -f --iterations=50 imported/w3c/web-platform-tests/navigation-api/navigation-methods/return-value/back-204-205-download.html

At 286180@main the results changed:
From:
Regressions: Unexpected timeouts (1)
  imported/w3c/web-platform-tests/navigation-api/navigation-methods/return-value/back-204-205-download.html [ Timeout ]
To:
Unexpected flakiness: timeouts (1)
  imported/w3c/web-platform-tests/navigation-api/navigation-methods/return-value/back-204-205-download.html [ Pass Failure Timeout ]

History:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fnavigation-api%2Fnavigation-methods%2Freturn-value%2Fback-204-205-download.html&style=debug&platform=mac

Diff:
+FAIL: Timed out waiting for notifyDone to be called
 
 
-FAIL back() promises to 204s never settle assert_unreached: onunload should not be called Reached unreachable code
-FAIL back() promises to 205s never settle assert_unreached: onunload should not be called Reached unreachable code
-PASS back() promises to Content-Disposition: attachment responses never settle
-

[Radar WebKit Bug Importer]

<rdar://problem/143709837>

[EWS]

Test gardening commit 289435@main (2319857212b5): <https://commits.webkit.org/289435@main>

Reviewed commits have been landed. Closing PR #39602 and removing active labels.