Filed by: rgurzau [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=275375249&repo=mozilla-central
Full log: https://queue.taskcluster.net/v1/task/fmXi5qvtRW6-86j-eE2UTQ/runs/0/artifacts/public/logs/live_backing.log

[task 2019-11-08T18:16:11.367Z] 18:16:11 INFO - GECKO(9215) | console.log: "[DISPATCH] action type:" "ADD_DEVICE"
[task 2019-11-08T18:16:11.368Z] 18:16:11 INFO - GECKO(9215) | console.log: "[DISPATCH] action type:" "ADD_DEVICE_TYPE"
[task 2019-11-08T18:16:11.371Z] 18:16:11 INFO - GECKO(9215) | console.log: "[DISPATCH] action type:" "LOAD_DEVICE_LIST_END"
[task 2019-11-08T18:16:11.407Z] 18:16:11 INFO - Tab added and finished loading
[task 2019-11-08T18:16:11.407Z] 18:16:11 INFO - Adding a new tab with URL: http://example.com/browser/devtools/client/responsive/test/browser/contextual_identity.html
[task 2019-11-08T18:16:11.443Z] 18:16:11 INFO - Console message: [JavaScript Error: "The character encoding of the HTML document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the page must be declared in the document or in the transfer protocol." {file: "http://example.com/browser/devtools/client/responsive/test/browser/contextual_identity.html" line: 0}]
[task 2019-11-08T18:16:11.481Z] 18:16:11 INFO - Tab added and finished loading
[task 2019-11-08T18:16:11.482Z] 18:16:11 INFO - Console message: [JavaScript Error: "The character encoding of the HTML document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the page must be declared in the document or in the transfer protocol." {file: "http://example.com/browser/devtools/client/responsive/test/browser/contextual_identity.html" line: 0}]
[task 2019-11-08T18:16:11.498Z] 18:16:11 INFO - TEST-PASS | devtools/client/responsive/test/browser/browser_contextual_identity.js | should only receive messages from the same user context - "Message from user context #2" == "Message from user context #2" -
[task 2019-11-08T18:16:11.515Z] 18:16:11 INFO - Removing tab.
[task 2019-11-08T18:16:11.517Z] 18:16:11 INFO - Waiting for event: 'TabClose' on [object XULElement].
[task 2019-11-08T18:16:11.545Z] 18:16:11 INFO - Got event: 'TabClose' on [object XULElement].
[task 2019-11-08T18:16:11.546Z] 18:16:11 INFO - Tab removed and finished closing
[task 2019-11-08T18:16:11.547Z] 18:16:11 INFO - Leaving test bound
[task 2019-11-08T18:16:11.582Z] 18:16:11 INFO - TEST-PASS | devtools/client/responsive/test/browser/browser_contextual_identity.js | The main process DebuggerServer has no pending connection when the test ends -
[task 2019-11-08T18:16:11.598Z] 18:16:11 INFO - TEST-UNEXPECTED-PASS | devtools/client/responsive/test/browser/browser_contextual_identity.js | We expect at least one assertion to fail because this test file is marked as fail-if in the manifest. -
[task 2019-11-08T18:16:11.598Z] 18:16:11 INFO - TEST-INFO | expected FAIL
[task 2019-11-08T18:16:11.599Z] 18:16:11 INFO - GECKO(9215) | MEMORY STAT | vsize 3018MB | residentFast 369MB | heapAllocated 150MB
[task 2019-11-08T18:16:11.599Z] 18:16:11 INFO - TEST-OK | devtools/client/responsive/test/browser/browser_contextual_identity.js | took 1962ms

Tentatively moving all bugs whose summaries mention "Fission" (or other Fission-related keywords) but are not assigned to a Fission Milestone to the "?" triage milestone.

This will generate a lot of bugmail, so you can filter your bugmail for the following UUID and delete them en masse:

0ee3c76a-bc79-4eb2-8d12-05dc0b68e732

Blocks Fission mochitests milestone (M4.1)

This test was most probably created by browsing https://searchfox.org/mozilla-central/source/browser/components/contextualidentity/test/browser for some reasonable way to ensure two tabs were properly isolated even with RDM.
Here's the same pattern we probably copied from: https://searchfox.org/mozilla-central/source/browser/components/contextualidentity/test/browser/browser_broadcastchannel.js#63-111

For RDM, the actual sending of messages is not too relevant, but it's just nice to have some validation that different containers are still isolated when RDM is active.

So, this test might probably still make sense to keep as is, even after the new RDM (which is embedded into the browser UI, and does not rely on a nested <iframe mozbrowser>) is released.

As to whether this bug should block Fission M4.1, I'm not sure. If the test only fails today with fission with the old RDM, then it makes no sense to fix that now. Better wait for the new RDM to be enabled as it will probably change how this test runs.

So I think we should disable this test for now and not block Fission M4.1.

If the test only fails today with fission with the old RDM, then it makes no
sense to fix that now. Better wait for the new RDM to be enabled as it will
probably change how this test runs.

https://hg.mozilla.org/mozilla-central/rev/a3ef45fac6c2