Filed by: csabou [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=315859425&repo=mozilla-central
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/d0fLdk4xTxGHujf-dovFKQ/runs/0/artifacts/public/logs/live_backing.log

[task 2020-09-16T16:47:59.670Z] 16:47:59     INFO - TEST-PASS | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | Container for [undefined id="root" iframe #document html body id="com"] has no children - 
[task 2020-09-16T16:47:59.671Z] 16:47:59     INFO - Navigate the test iframe to http://example.net/document-builder.sjs?html=<div id=net>net
[task 2020-09-16T16:47:59.672Z] 16:47:59     INFO - Update the src attribute of the iframe tag
[task 2020-09-16T16:47:59.673Z] 16:47:59     INFO - Wait for frameLoad/newRoot to resolve
[task 2020-09-16T16:47:59.673Z] 16:47:59     INFO - Buffered messages logged at 16:46:36
[task 2020-09-16T16:47:59.674Z] 16:47:59     INFO - Wait for pending children updates
[task 2020-09-16T16:47:59.675Z] 16:47:59     INFO - Buffered messages finished
[task 2020-09-16T16:47:59.675Z] 16:47:59     INFO - TEST-UNEXPECTED-FAIL | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | Test timed out - 
[task 2020-09-16T16:48:00.515Z] 16:48:00     INFO - Removing tab.
[task 2020-09-16T16:48:00.516Z] 16:48:00     INFO - Waiting for event: 'TabClose' on [object XULElement].
[task 2020-09-16T16:48:00.543Z] 16:48:00     INFO - Got event: 'TabClose' on [object XULElement].
[task 2020-09-16T16:48:00.567Z] 16:48:00     INFO - GECKO(2823) | [Parent 2823, Main Thread] WARNING: '!inner', file /builds/worker/checkouts/gecko/dom/ipc/jsactor/JSWindowActorProtocol.cpp, line 172
[task 2020-09-16T16:48:00.568Z] 16:48:00     INFO - GECKO(2823) | [Parent 2823, Main Thread] WARNING: '!inner', file /builds/worker/checkouts/gecko/dom/ipc/jsactor/JSWindowActorProtocol.cpp, line 172
[task 2020-09-16T16:48:00.576Z] 16:48:00     INFO - Tab removed and finished closing
[task 2020-09-16T16:48:00.577Z] 16:48:00     INFO - Wait until the new target has been processed by TargetList
[task 2020-09-16T16:48:00.578Z] 16:48:00     INFO - Find and expand the shadow DOM host matching selector #root.
[task 2020-09-16T16:48:00.582Z] 16:48:00     INFO - Not taking screenshot here: see the one that was previously logged
[task 2020-09-16T16:48:00.583Z] 16:48:00     INFO - TEST-UNEXPECTED-FAIL | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | Uncaught exception received from previously timed out test - at resource://devtools/shared/protocol/Front/FrontClassWithSpec.js:28 - Error: Can not send request 'querySelector' because front 'domwalker' is already destroyed.
[task 2020-09-16T16:48:00.584Z] 16:48:00     INFO - Stack trace:
[task 2020-09-16T16:48:00.585Z] 16:48:00     INFO - generateRequestMethods/</frontProto[name]@resource://devtools/shared/protocol/Front/FrontClassWithSpec.js:28:15
[task 2020-09-16T16:48:00.586Z] 16:48:00     INFO - querySelector@resource://devtools/client/fronts/walker.js:145:34
[task 2020-09-16T16:48:00.587Z] 16:48:00     INFO - getNodeFront@chrome://mochitests/content/browser/devtools/client/inspector/test/shared-head.js:224:17
[task 2020-09-16T16:48:00.588Z] 16:48:00     INFO - assertMarkupViewAsTree@chrome://mochitests/content/browser/devtools/client/inspector/test/head.js:1178:27
[task 2020-09-16T16:48:00.590Z] 16:48:00     INFO - @chrome://mochitests/content/browser/devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js:53:9
[task 2020-09-16T16:48:00.591Z] 16:48:00     INFO - Async*Tester_execTest/<@chrome://mochikit/content/browser-test.js:1069:34
[task 2020-09-16T16:48:00.592Z] 16:48:00     INFO - Tester_execTest@chrome://mochikit/content/browser-test.js:1109:11
[task 2020-09-16T16:48:00.593Z] 16:48:00     INFO - nextTest/<@chrome://mochikit/content/browser-test.js:932:14
[task 2020-09-16T16:48:00.594Z] 16:48:00     INFO - SimpleTest.waitForFocus/waitForFocusInner/focusedOrLoaded/<@chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:1037:23
[task 2020-09-16T16:48:00.645Z] 16:48:00     INFO - TEST-PASS | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | The main process DevToolsServer has no pending connection when the test ends - 
[task 2020-09-16T16:48:00.682Z] 16:48:00     INFO - GECKO(2823) | MEMORY STAT | vsize 3451MB | residentFast 400MB | heapAllocated 122MB
[task 2020-09-16T16:48:00.683Z] 16:48:00     INFO - GECKO(2823) | ###!!! [Parent][RunMessage] Error: Channel closing: too late to send/recv, messages will be lost
[task 2020-09-16T16:48:00.684Z] 16:48:00     INFO - TEST-OK | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | took 91353ms
[task 2020-09-16T16:48:00.717Z] 16:48:00     INFO - GECKO(2823) | [Child 2971: Main Thread]: I/DocShellAndDOMWindowLeak ++DOCSHELL 0x7f65cbf9a400 == 1 [pid = 2971] [id = {090f0c41-4622-4d47-979c-4c3f96bd7980}]
[task 2020-09-16T16:48:00.719Z] 16:48:00     INFO - GECKO(2823) | [Child 2971: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 1 (0x7f65e8593180) [pid = 2971] [serial = 26] [outer = (nil)]
[task 2020-09-16T16:48:00.720Z] 16:48:00     INFO - GECKO(2823) | [Child 2971: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 2 (0x7f65cbf9bc00) [pid = 2971] [serial = 27] [outer = 0x7f65e8593180]
[task 2020-09-16T16:48:00.818Z] 16:48:00     INFO - checking window state
[task 2020-09-16T16:48:00.874Z] 16:48:00     INFO - GECKO(2823) | [Parent 2823: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7f2e47c06800 == 7 [pid = 2823] [id = {15b1ea8c-5492-405b-b08d-9b333834e696}] [url = chrome://devtools/content/inspector/markup/markup.xhtml]
[task 2020-09-16T16:48:00.875Z] 16:48:00     INFO - GECKO(2823) | [Parent 2823: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7f2e384b6800 == 6 [pid = 2823] [id = {7b749441-b153-4ba7-9bd0-e83123de0f59}] [url = chrome://devtools/content/inspector/index.xhtml]
[task 2020-09-16T16:48:00.975Z] 16:48:00     INFO - TEST-START | devtools/client/inspector/test/browser_inspector_fission_switch_target.js```

There have been 32 failures since the bug has been created:

• 13 failures on Linux 18.04 x64 debug
• 8 failures on Linux 18.04 x64 shippable opt
• 11 failures on Windows 10 x64 Shippable opt

Recent failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=316184822&repo=mozilla-central&lineNumber=6607

[task 2020-09-19T23:29:42.337Z] 23:29:42 INFO - TEST-PASS | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | Container for [undefined id="root" iframe #document html body id="com"] has no children -
[task 2020-09-19T23:29:42.338Z] 23:29:42 INFO - Navigate the test iframe to http://example.net/document-builder.sjs?html=<div id=net>net
[task 2020-09-19T23:29:42.339Z] 23:29:42 INFO - Update the src attribute of the iframe tag
[task 2020-09-19T23:29:42.340Z] 23:29:42 INFO - Wait for frameLoad/newRoot to resolve
[task 2020-09-19T23:29:42.342Z] 23:29:42 INFO - Wait for pending children updates
[task 2020-09-19T23:29:42.343Z] 23:29:42 INFO - Buffered messages finished
[task 2020-09-19T23:29:42.344Z] 23:29:42 INFO - TEST-UNEXPECTED-FAIL | devtools/client/inspector/test/browser_inspector_fission_frame_navigation.js | Test timed out -
[task 2020-09-19T23:29:42.345Z] 23:29:42 INFO - Removing tab.
[task 2020-09-19T23:29:42.345Z] 23:29:42 INFO - Waiting for event: 'TabClose' on [object XULElement].
[task 2020-09-19T23:29:42.346Z] 23:29:42 INFO - Got event: 'TabClose' on [object XULElement].
[task 2020-09-19T23:29:42.347Z] 23:29:42 INFO - Tab removed and finished closing
[task 2020-09-19T23:29:42.347Z] 23:29:42 INFO - Wait until the new target has been processed by TargetList
[task 2020-09-19T23:29:42.348Z] 23:29:42 INFO - Find and expand the shadow DOM host matching selector #root.
[task 2020-09-19T23:29:42.351Z] 23:29:42 INFO - Not taking screenshot here: see the one that was previously logged

Seems to be related to bug 1664438. Alexandre, could you look into this?
Thank you.

Set release status flags based on info from the regressing bug 1664438

https://hg.mozilla.org/mozilla-central/rev/e4c429d3ef53