#[markdown(off)]
Filed by: rgurzau [at] mozilla.com

https://treeherder.mozilla.org/logviewer.html#?job_id=241839986&repo=autoland

https://queue.taskcluster.net/v1/task/M-Q3sGCoRy-nV30gU93D9A/runs/0/artifacts/public/logs/live_backing.log

[task 2019-04-22T18:33:13.622Z] 18:33:13 INFO - GECKO(1068) | ERROR: GC found live SharedScriptData 0x7f4d5c2451f0 with ref count 2 at shutdown
[task 2019-04-22T18:33:13.623Z] 18:33:13 INFO - GECKO(1068) | ERROR: GC found live SharedScriptData 0x7f4d5ae4ee00 with ref count 2 at shutdown
[task 2019-04-22T18:33:13.624Z] 18:33:13 INFO - GECKO(1068) | Assertion failure: isEmpty() (failing this assertion means this LinkedList's creator is buggy: it should have removed all this list's elements before the list's destruction), at /builds/worker/workspace/build/src/obj-firefox/dist/include/mozilla/LinkedList.h:433
[task 2019-04-22T18:33:13.625Z] 18:33:13 INFO - GECKO(1068) | [ACTION] SET_VIEWPORT - {"type":"SET_VIEWPORT","viewport":{"start":{"line":3,"column":0},"end":{"line":14,"column":91}}}
[task 2019-04-22T18:33:13.626Z] 18:33:13 INFO - GECKO(1068) | [Parent 1068, Main Thread] ###!!! ASSERTION: Unexpected UpdateTransformLayer hint: '!(aChange & nsChangeHint_UpdateTransformLayer) || nsLayoutUtils::GetPrimaryFrameFromStyleFrame(aFrame) ->IsTransformed() || aFrame->StyleDisplay()->HasTransformStyle()', file /builds/worker/workspace/build/src/layout/base/RestyleManager.cpp, line 1200
[task 2019-04-22T18:33:13.627Z] 18:33:13 INFO - GECKO(1068) | #01: mozilla::RestyleManager::DoProcessPendingRestyles(mozilla::ServoTraversalFlags) [xpcom/ds/nsTArray.h:347]
[task 2019-04-22T18:33:13.628Z] 18:33:13 INFO -

It looks like this is happening in mozilla::RestyleManager::DoProcessPendingRestyles. Given the other log spew happening before the assertion, I suspect this test is leaking, and this assertion is a side effect of a leak.

What makes you think that? AFAICT there's only a non-fatal assertion in DoProcessPendingRestyles due to some JS code that is still running and calls into getBoundingClientRects().

But seems unlikely that the leak comes from the style system. The issue is the JS code that's calling into it after shutdown, which is presumably what leaks.

I think there's a leak because there's a bunch of log spam like this:
ERROR: GC found live SharedScriptData 0x7f2facbe6ac0 with ref count 2 at shutdown

Yeah, it doesn't seem likely that the leak is due to the style system, but it is hard to say without more evidence one way or the other.

The oranges are all in the mochitest-devtools-chrome-sw-e10s-10 test suite, whatever that is.