Treeherder Bug Filer Reporter
	Description • 7 years ago
treeherder

Filed by: wkocher [at] mozilla.com

https://treeherder.mozilla.org/logviewer.html#?job_id=88587781&repo=autoland

https://archive.mozilla.org/pub/firefox/tinderbox-builds/autoland-win32-debug/1491314427/autoland_win7_vm-debug_test-marionette-e10s-bm138-tests1-windows-build326.txt.gz

	Henrik Skupin [:whimboo][⌚️UTC+1] Assignee
	Comment 1 • 7 years ago

08:05:07     INFO -  Traceback (most recent call last):
08:05:07     INFO -    File "c:\slave\test\build\venv\lib\site-packages\marionette_harness\marionette_test\testcases.py", line 166, in run
08:05:07     INFO -      testMethod()
08:05:07     INFO -    File "c:\slave\test\build\tests\marionette\tests\testing\marionette\harness\marionette_harness\tests\unit\test_navigation.py", line 464, in test_timeout_error
08:05:07     INFO -      self.assertEqual(self.marionette.find_element(By.ID, "delay").text, "4")
08:05:07     INFO -    File "c:\slave\test\build\venv\lib\site-packages\marionette_driver\marionette.py", line 1938, in find_element
08:05:07     INFO -      return self._send_message("findElement", body, key="value")
08:05:07     INFO -    File "c:\slave\test\build\venv\lib\site-packages\marionette_driver\decorators.py", line 23, in _
08:05:07     INFO -      return func(*args, **kwargs)
08:05:07     INFO -    File "c:\slave\test\build\venv\lib\site-packages\marionette_driver\marionette.py", line 735, in _send_message
08:05:07     INFO -      self._handle_error(err)
08:05:07     INFO -    File "c:\slave\test\build\venv\lib\site-packages\marionette_driver\marionette.py", line 768, in _handle_error
08:05:07     INFO -      raise errors.lookup(error)(message, stacktrace=stacktrace)

Interesting here is that this is happening now after a forward navigation. So it means we somehow return too early from it, and the element 'delay' is not present yet. This might have been caused by the patches on bug 1291320. It looks like a low intermittent failure.

	Joel Maher ( :jmaher ) (UTC -8)
	Comment 3 • 7 years ago

I ran into this in my data from activedata about failures in real time.

	Joel Maher ( :jmaher ) (UTC -8)
	Comment 5 • 7 years ago

:whimboo, can you put this in your queue to debug or help find the right person to look at this?  The failure rate is steady and I see us needing to address this in the coming weeks.

	Henrik Skupin [:whimboo][⌚️UTC+1] Assignee
	Comment 6 • 7 years ago

Here the exact failing code:

https://dxr.mozilla.org/mozilla-central/rev/a374c35469935a874fefe64d3e07003fc5bc8884/testing/marionette/harness/marionette_harness/tests/unit/test_navigation.py#444-453

This is all after the last call to `goBack()`. Given that a timeout error was raised, the command returns before the expected page has been fully loaded. So we have this extra call to `getCurrentUrl`. 

Now the interesting fact is that this command doesn't care about the page load status. And as such returns the new URL once it appears in the location bar. The test now tries to find the element `delay` which might not be present yet.

To fix that we should move the `find_element()` call into `Wait().until()`.

I will try to have a fix by today.

	Andreas Tolfsen ❲:ato❳
	Comment 9 • 7 years ago
mozreview-review

Comment on attachment 8860897 [details]
Bug 1353447 - Fix race condition in TestBackForwardNavigation.test_timeout_error.

https://reviewboard.mozilla.org/r/132910/#review135742

	Pulsebot
	Comment 10 • 7 years ago

Pushed by hskupin@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/b4d2716a7b58
Fix race condition in TestBackForwardNavigation.test_timeout_error. r=ato

	Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)
	Comment 11 • 7 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/b4d2716a7b58

	Ryan VanderMeulen [:RyanVM]
	Comment 12 • 7 years ago
bugherder uplift

https://hg.mozilla.org/releases/mozilla-beta/rev/5938ef3ed0db

	Ryan VanderMeulen [:RyanVM]
	Comment 14 • 7 years ago

If you want this to land on esr52 too, it'll need a rebased patch.

	Henrik Skupin [:whimboo][⌚️UTC+1] Assignee
	Comment 15 • 7 years ago

So far there are no crashes on mozilla-esr52, so I don't think it's useful to spend the time on a backport patch. If it starts failing there, we can re-evaluate.

	BMO Automation
	Comment 17 • 1 year ago

Moving bug to Testing::Marionette Client and Harness component per bug 1815831.