1134984 - Mozmill fails to send appInfo object in Firefox Nightly 38.0a1 builds (past Feb 17th) due to EME changes in the AOM

Status: RESOLVED FIXED

(Testing Graveyard :: Mozmill, defect)

Description

[Henrik Skupin [:whimboo][⌚️UTC+2]]

We got dozen of failures with Mozmill on latest Firefox Nightly 38.0a1 builds in the past days. It looks like a change in Firefox caused this regression. It happens since Feb 18th.

Here the output directly after startup of the browser:

Traceback (most recent call last):
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\lib\site-packages\mozmill_automation\testrun.py", line 469, in run_tests
    TestRun.run_tests(self)
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\lib\site-packages\mozmill_automation\testrun.py", line 306, in run_tests
    self._mozmill.run(tests, self.options.restart)
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\lib\site-packages\mozmill\__init__.py", line 452, in run
    frame = self.run_test_file(frame or self.start_runner(),
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\lib\site-packages\mozmill\__init__.py", line 365, in start_runner
    appinfo = self.get_appinfo()
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\lib\site-packages\mozmill\__init__.py", line 482, in get_appinfo
    app_info = json.loads(mozmill.getApplicationDetails())
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\Lib\json\__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "c:\jenkins\workspace\mozilla-central_addons\mozmill-env-windows\python\Lib\json\decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
TypeError: expected string or buffer

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Regression range for nightly builds:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=09f4968d5f42&tochange=9696d1c4b3ba

I will dig into further to figure out what's wrong. As it looks like jsbridge is transferring a None object for the appinfo details. I assume it should be related to networking given that I cannot see a failure in the browser console.

Comment 2

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Pushlog from inbound: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=b87c58ef8667&tochange=883b84c33c4b

So this is a regression by bug 1089867. I assume we fail to stringify or send some plugin related data via jsbridge. I will dig further if that is our problem in Mozmill or something which regressed in Firefox.

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+2]]

So the problematic bits here are indeed related to the GMP plugin changes. Specifically it is the `_plugin` property as attached to an AOM addon entry, which is not serializable:

---- OpenH264 Video Codec provided by Cisco Systems, Inc. _plugin
**** cannot stringify: [object Object]

Given the underscore prefix it looks like it is private and should not be used. Georg, mind giving me a quick feedback here?

I will go ahead and make our addon information retrieval code more robust in terms of those non serializable objects.

Comment 4

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Attachment: fix v1

This fixes the problem by not trying to retrieve all possible properties of add-ons, which we don't need anyway. Lets only focus on the important ones, which are in use in our dashboard:

http://mozmill-release.blargon7.com/#/functional/report/62e124507768503a8f985d202f10cc72

Comment 5

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Mozmill 2.1 code is currently broken with our Mozmill tests for Firefox. So we cannot get this version released yet. So I'm going to release a 2.0.10 with this patch.

Comment 6

[Henrik Skupin [:whimboo][⌚️UTC+2]]

https://github.com/mozilla/mozmill/commit/6c0948d80eebcbb104ce7a776c65aeae634970dd (master)
https://github.com/mozilla/mozmill/commit/959f35bb16f9af76a447abffc54422ce1fa1f616 (hotfix-2.0)

Comment 7

[Georg Fritzsche [:gfritzsche]]

(In reply to Henrik Skupin (:whimboo) from comment #3)
> So the problematic bits here are indeed related to the GMP plugin changes.
> Specifically it is the `_plugin` property as attached to an AOM addon entry,
> which is not serializable:
> 
> ---- OpenH264 Video Codec provided by Cisco Systems, Inc. _plugin
> **** cannot stringify: [object Object]
> 
> Given the underscore prefix it looks like it is private and should not be
> used. Georg, mind giving me a quick feedback here?
> 
> I will go ahead and make our addon information retrieval code more robust in
> terms of those non serializable objects.

Definitely private. Not sure off-hand why it's not serializable and we could technically wrap this away, but only retrieving a set of properties you need in your patch sounds much better anyway.