This request is for enabling Mochitests-Fission on Linux 64 debug builds with WebRender on tier1.

Should I simply skip all the current failures?

Should mochitest-gpu, mochitest-webgl, mochitest-media be included, or just mochitest-plain?

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=830b96cf768acecdd52326061a48d51baf33ed9c

I believe we need to include Mochitest-plain, mochitest-browser-chrome, mochitest-media, mochitest-webgl.
NI'ing Kris to confirm too.

mochitest-browser-chrome is not normally run on linux64-qr.

https://searchfox.org/mozilla-central/rev/45f30e1d19bde27bf07e47a0a5dd0962dd27ba18/taskcluster/ci/test/test-sets.yml#202

We definitely need the bc tests. I don't care much whether they run in QR mode or not, just as long as they run.

We can't include mochitest-gpu, since those are mochitest-chrome tests which run with e10s disabled, and therefore can't enable fission.

We do want media and webgl, though.

I'm marking high-frequency intermittent failures as blockers. Most of these already have skip-if(fission) patches up for review.

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=76eb874c8dd988354049924ad8ced74c5c04255a

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=fd941c9fa844e19b3f49a1be88a15782abf3810b

This changes certain fission tests to run tier 1 and start running on integration branches:
linux64-qr/debug mochitest-plain
linux64-qr/debug mochitest-media
linux64-qr/debug mochitest-webgl*
linux64/debug browser-chrome
All other fission tests continue to run as tier 2 and only on central and try.

Backed out changeset 666a99f27c23 (Bug 1582881) for high-frequency mochitest failures at test_ext_contentscript_about_blank.html

Backout: https://hg.mozilla.org/integration/autoland/rev/3840361d201f9e7c65e1b0189b7d60c46ebc79e6

Push that started the failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception&revision=666a99f27c2355c5df34e9302c0c0a70e39a02be&selectedJob=268694082

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=268694082&repo=autoland&lineNumber=6397

Fission failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&fromchange=e729376dff049ba4f17cf814203117f8a58e237c&searchStr=fission&group_state=expanded

It looks like there are at least 3 tests that need to be skipped or fixed to proceed. (There may be a couple more, in the dom/push task...need to revisit once these are resolved). These failures were not evident in yesterday's try pushes -- the change is concerning.

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=7b23678e0629bf8491a754e2ae266f483ac7ee9f

With those 3 tests skipped, test results are better, but there are several other test failures:

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=cb21f7c5c25e54663970d83736c3ef1d1abb0e2c

I'll try again with the (much appreciated) new patch from bug 1584483....

Bug 1582531 also just landed, which re-enabled a lot of tests which had previously been skipped but now appeared to pass. I think it's unavoidable that some of those will turn out to be intermittent failures that didn't show up in any of our try runs, in which case they should probably be re-skipped with an appropriate comment.

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=25744bdbd892730094db36c7c28dc2e762861476

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=af67e46ce82d19011f8d7efc6940744865f23b46

suggests this bug might be able to proceed with the additional manifest updates in bug 1582531 plus additional updates to resolve or skip:

• test_permissions.html (bug 1575185)
• test_navigate_to.html (bug 1580643)
• test_sanitize_domain.html (bug 1584471)

https://treeherder.mozilla.org/#/jobs?repo=try&tier=1%2C2%2C3&revision=fbcce762703b4b0fa323302e4062cef09b545db8

...there are still several intermittents, but none are very high frequency. I'll try landing again.

https://hg.mozilla.org/mozilla-central/rev/49ef9afb62bb