Filed by: sstanca [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer?job_id=410090619&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/YzX_OOLwRw6Hhs2cDSz8gw/runs/0/artifacts/public/logs/live_backing.log

[task 2023-03-24T14:06:09.101Z] 14:06:09     INFO -  TEST-PASS | xpcshell.ini:toolkit/mozapps/extensions/test/xpcshell/test_upgrade.js | took 1408ms
[task 2023-03-24T14:06:09.103Z] 14:06:09     INFO -  Retrying tests that failed when run in parallel.
[task 2023-03-24T14:06:09.104Z] 14:06:09     INFO -  TEST-START | dom/webtransport/test/xpcshell/test_simple_conn.js
[task 2023-03-24T14:06:41.287Z] 14:06:41  WARNING -  TEST-UNEXPECTED-FAIL | dom/webtransport/test/xpcshell/test_simple_conn.js | xpcshell return code: 0
[task 2023-03-24T14:06:41.287Z] 14:06:41     INFO -  TEST-INFO took 32182ms
[task 2023-03-24T14:06:41.287Z] 14:06:41     INFO -  >>>>>>>
[task 2023-03-24T14:06:41.288Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: Couldn't get the user appdata directory. Crash events may not be produced.: file /builds/worker/checkouts/gecko/toolkit/crashreporter/nsExceptionHandler.cpp:2908
[task 2023-03-24T14:06:41.288Z] 14:06:41     INFO -  (xpcshell/head.js) | test MAIN run_test pending (1)
[task 2023-03-24T14:06:41.289Z] 14:06:41     INFO -  (xpcshell/head.js) | test run_next_test 0 pending (2)
[task 2023-03-24T14:06:41.289Z] 14:06:41     INFO -  (xpcshell/head.js) | test MAIN run_test finished (2)
[task 2023-03-24T14:06:41.290Z] 14:06:41     INFO -  running event loop
[task 2023-03-24T14:06:41.290Z] 14:06:41     INFO -  PID 10258 | Couldn't convert chrome URL: chrome://branding/locale/brand.properties
[task 2023-03-24T14:06:41.290Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: Could not get the program name for a cubeb stream.: 'NS_SUCCEEDED(rv)', file /builds/worker/checkouts/gecko/dom/media/CubebUtils.cpp:430
[task 2023-03-24T14:06:41.290Z] 14:06:41     INFO -  dom/webtransport/test/xpcshell/test_simple_conn.js | Starting setup setup
[task 2023-03-24T14:06:41.291Z] 14:06:41     INFO -  (xpcshell/head.js) | test setup pending (2)
[task 2023-03-24T14:06:41.291Z] 14:06:41     INFO -  TEST-PASS | dom/webtransport/test/xpcshell/test_simple_conn.js | setup - [setup : 53] "34395" != null
[task 2023-03-24T14:06:41.292Z] 14:06:41     INFO -  TEST-PASS | dom/webtransport/test/xpcshell/test_simple_conn.js | setup - [setup : 54] "34395" != ""
[task 2023-03-24T14:06:41.293Z] 14:06:41     INFO -  (xpcshell/head.js) | test run_next_test 0 finished (2)
[task 2023-03-24T14:06:41.294Z] 14:06:41     INFO -  (xpcshell/head.js) | test run_next_test 1 pending (2)
[task 2023-03-24T14:06:41.294Z] 14:06:41     INFO -  (xpcshell/head.js) | test setup finished (2)
[task 2023-03-24T14:06:41.295Z] 14:06:41     INFO -  "CONSOLE_MESSAGE: (info) No chrome package registered for chrome://branding/locale/brand.properties"
[task 2023-03-24T14:06:41.299Z] 14:06:41     INFO -  dom/webtransport/test/xpcshell/test_simple_conn.js | Starting test_webtransport_create
[task 2023-03-24T14:06:41.300Z] 14:06:41     INFO -  (xpcshell/head.js) | test test_webtransport_create pending (2)
[task 2023-03-24T14:06:41.300Z] 14:06:41     INFO -  (xpcshell/head.js) | test run_next_test 1 finished (2)
[task 2023-03-24T14:06:41.301Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Socket Thread] WARNING: NS_ENSURE_TRUE(inst) failed: file StaticComponents.cpp:12106
[task 2023-03-24T14:06:41.302Z] 14:06:41     INFO -  Unexpected exception WebTransportError: WebTransport connection rejected
[task 2023-03-24T14:06:41.302Z] 14:06:41     INFO -  exiting test
[task 2023-03-24T14:06:41.303Z] 14:06:41     INFO -  PID 10258 | JavaScript error: , line 0: WebTransportError: WebTransport connection rejected
[task 2023-03-24T14:06:41.304Z] 14:06:41     INFO -  "CONSOLE_MESSAGE: (error) [JavaScript Error: "WebTransportError: WebTransport connection rejected"]"
[task 2023-03-24T14:06:41.304Z] 14:06:41  WARNING -  TEST-UNEXPECTED-FAIL | dom/webtransport/test/xpcshell/test_simple_conn.js | test_webtransport_create - [test_webtransport_create : 266] A promise chain failed to handle a rejection: WebTransport connection rejected - stack: (No stack available.)
[task 2023-03-24T14:06:41.304Z] 14:06:41     INFO -  Rejection date: Fri Mar 24 2023 14:06:41 GMT+0000 (Coordinated Universal Time) - false == true
[task 2023-03-24T14:06:41.305Z] 14:06:41     INFO -  resource://testing-common/PromiseTestUtils.sys.mjs:assertNoUncaughtRejections:266
[task 2023-03-24T14:06:41.306Z] 14:06:41     INFO -  /builds/worker/workspace/build/tests/xpcshell/head.js:_execute_test:586
[task 2023-03-24T14:06:41.306Z] 14:06:41     INFO -  -e:null:1
[task 2023-03-24T14:06:41.307Z] 14:06:41     INFO -  exiting test
[task 2023-03-24T14:06:41.307Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Socket Thread] WARNING: cannot post event if not initialized: file /builds/worker/checkouts/gecko/netwerk/protocol/http/nsHttpConnectionMgr.cpp:232
[task 2023-03-24T14:06:41.307Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: Extra shutdown CC: 'i < NORMAL_SHUTDOWN_COLLECTIONS', file /builds/worker/checkouts/gecko/xpcom/base/nsCycleCollector.cpp:3396
[task 2023-03-24T14:06:41.308Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: OOPDeinit() without successful OOPInit(): file /builds/worker/checkouts/gecko/toolkit/crashreporter/nsExceptionHandler.cpp:3376
[task 2023-03-24T14:06:41.308Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: NS_ENSURE_TRUE(Preferences::InitStaticMembers()) failed: file /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:4689
[task 2023-03-24T14:06:41.309Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: XPCOM object PerThreadData destroyed from static ctor/dtor: file /builds/worker/checkouts/gecko/xpcom/base/nsTraceRefcnt.cpp:216
[task 2023-03-24T14:06:41.309Z] 14:06:41     INFO -  PID 10258 | [Parent 10258, Main Thread] WARNING: XPCOM object SourceList destroyed from static ctor/dtor: file /builds/worker/checkouts/gecko/xpcom/base/nsTraceRefcnt.cpp:216
[task 2023-03-24T14:06:41.310Z] 14:06:41     INFO -  <<<<<<<
[task 2023-03-24T14:06:41.310Z] 14:06:41     INFO -  TEST-START | dom/webtransport/test/xpcshell/test_simple_stream.js
[task 2023-03-24T14:07:13.478Z] 14:07:13  WARNING -  TEST-UNEXPECTED-FAIL | dom/webtransport/test/xpcshell/test_simple_stream.js | xpcshell return code: 0
[task 2023-03-24T14:07:13.479Z] 14:07:13     INFO -  TEST-INFO took 32182ms

First occurrence in this range of retriggers and backfills

Most probably caused by Bug 1823861.
John, can you take a look please?
Thank you.

That doesn't seem likely to me. Bug 1823861 only affects old versions of Windows, and the code path is only active when a USB security token is used.

Done some more digging and the failures seems to stop at https://bugzilla.mozilla.org/show_bug.cgi?id=1818828 according to this range.
Ed, could you please take a look at this?
Thanks,

Set release status flags based on info from the regressing bug 1818828

This is probably an issue with our http3 test server and not something in the implementation or tests. It is also likely that this issue is the same as the ones noted in Bug 1824190 and Bug 1824192.
I haven't had any luck reproducing this locally as-is, but will continue to poke at it.

Set release status flags based on info from the regressing bug 1818828