Version 1.4 seems to break when django.templates.backends has not been initialized

[PamelaM]

This is clearly a bug caused by my recent PR.

  Coverage.py warning: Disabling plugin 'django_coverage_plugin.DjangoTemplatePlugin' due to an exception:
 Traceback (most recent call last):
   File "/home/teamcity/.virtualenvs/addgene1.8/local/lib/python2.7/site-packages/coverage/control.py", line 476, in _should_trace_internal
     file_tracer = plugin.file_tracer(canonical)
   File "/home/teamcity/.virtualenvs/addgene1.8/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 158, in file_tracer
     self.debug_checked = check_debug()
   File "/home/teamcity/.virtualenvs/addgene1.8/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 56, in check_debug
     if not hasattr(django.template.backends, "django"):

I'll work though a fix PR in the next two days.

Because of the chicken-and-egg issues of starting, I think the need for a test_project that can be used for full integration testing via subprocess calls is even more vital. There are too many "shenanigans" involved with getting coverage/django startup initialization order reversed and re-run during the current test process.

[PamelaM]

I can only reproduce it in one case where we're not using a management command, so this doesn't look like a complete show-stopper. Still looking at it

[ambivalentno]

I observe such behavior even if running with coverage run manage.py test (Django 1.6 project migrating to 1.8)

[jclgoodwin]

I've also observed such behaviour running with coverage run manage.py test (Django 1.10 project). But #33 fixes the problem for me 👍

[garyayo]

I just wanted to add that we've just recently started to experience this issue...

(backend) [17:43:43] gary:backend git:(dev*) $ coverage run ./manage.py test -v 2
Coverage.py warning: Disabling plugin 'django_coverage_plugin.DjangoTemplatePlugin' due to an exception:
Traceback (most recent call last):
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/coverage/control.py", line 476, in _should_trace_internal
    file_tracer = plugin.file_tracer(canonical)
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 158, in file_tracer
    self.debug_checked = check_debug()
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 56, in check_debug
    if not hasattr(django.template.backends, "django"):
AttributeError: 'module' object has no attribute 'backends'

We're currently running:

coverage==4.3.4
django-coverage-plugin==1.4
Django==1.9

Any idea how we can resolve this issue and move forward?

Thanks

[PamelaM]

Ned just released django-coverage-plugin==1.4.1 which should address the problems dealing wit deferred initialization of the backends.

Please check it out and let us know if it works for you.

[garyayo]

@PamelaM Thank you for getting back to me, I appreciate your response.

Since upgrading to django-coverage-plugin==1.4.1 we're now experiencing the following issue.

(backend) [8:55:09] gary:backend git:(dev*) $ pip freeze | grep coverage
coverage==4.3.4
django-coverage-plugin==1.4.1
(backend) [8:55:14] gary:backend git:(dev*) $ coverage run ./manage.py test -v 2
Coverage.py warning: Disabling plugin 'django_coverage_plugin.DjangoTemplatePlugin' due to an exception:
Traceback (most recent call last):
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/coverage/control.py", line 476, in _should_trace_internal
    file_tracer = plugin.file_tracer(canonical)
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 163, in file_tracer
    self.debug_checked = check_debug()
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 67, in check_debug
    for engine in django.template.engines.all():
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/template/utils.py", line 110, in all
    return [self[alias] for alias in self]
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/template/utils.py", line 101, in __getitem__
    engine = engine_cls(params)
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/template/backends/django.py", line 31, in __init__
    options['libraries'] = self.get_templatetag_libraries(libraries)
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/template/backends/django.py", line 49, in get_templatetag_libraries
    libraries = get_installed_libraries()
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/template/backends/django.py", line 132, in get_installed_libraries
    for app_config in apps.get_app_configs())
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/apps/registry.py", line 137, in get_app_configs
    self.check_apps_ready()
  File "/home/gary/dev/envs/backend/local/lib/python2.7/site-packages/django/apps/registry.py", line 124, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
AppRegistryNotReady: Apps aren't loaded yet.

Unfortunately it seems as if our best option at this point is to downgrade to django-coverage-plugin==1.3.1

[PamelaM]

I'll keep plugging away this weekend. I can see where you're getting the error, now I just need to figure out what my integration test environment is doing differently than your environment (since I'm not getting that error).

It's probably time to step back and rethink every part of the startup process. I'll probably also remove support for DJ 1.7 and earlier - if only to simplify the plugin.

Clearly, there are a number of variables. I see that you're running "Python==2.7.(something)". I'll assume you're still on "Django==1.9" and focus on that.

[garyayo]

Thanks @PamelaM.

You're correct. The error is occurring within our backend environment which is setup as

(backend) [9:38:06] gary:backend git:(dev*) $ python --version
Python 2.7.12
(backend) [9:38:36] gary:backend git:(dev*) $ pip freeze | grep Django
Django==1.9
(backend) [9:38:41] gary:backend git:(dev*) $ pip freeze | grep coverage
coverage==4.3.4
django-coverage-plugin==1.4.1 
(backend) [9:38:47] gary:backend git:(dev*) $

Thanks again. Please let me know if you need any additional information.

[PamelaM]

@garyayo Could you try with PR #38?
I think the fix will address both your issue and a number of other, similar ones.

Please let me know if it works for you.

Thanks
Pam

[garyayo]

@PamelaM Sorry for the delay in my response.

Any idea how I would be able to pull in that PR through pip? I have tried the following command with your PR commit pip install git+https://github.com/nedbat/django_coverage_plugin.git@4df203a0908ac638f6c6da2b2e53096eb29506e8 with no luck.

Would love to test out that PR for you.

[clokep]

@garyayo Use the following:
pip install https://codeload.github.com/nedbat/django_coverage_plugin/zip/4df203a0908ac638f6c6da2b2e53096eb29506e8

Note that if you already have django-coverage-plugin 1.4.1 installed pip won't upgrade to the new code because it's the same version number.

[garyayo]

Very excellent! Thank you @clokep!

@PamelaM I've very happy to say that my issue appears to have been resolved!

(backend) [9:10:42] gary:backend git:(dev*) $ pip install https://codeload.github.com/nedbat/django_coverage_plugin/zip/4df203a0908ac638f6c6da2b2e53096eb29506e8
Collecting https://codeload.github.com/nedbat/django_coverage_plugin/zip/4df203a0908ac638f6c6da2b2e53096eb29506e8
  Downloading https://codeload.github.com/nedbat/django_coverage_plugin/zip/4df203a0908ac638f6c6da2b2e53096eb29506e8
     | 30kB 942kB/s
Requirement already satisfied: Django>=1.4 in /home/gary/dev/envs/backend/lib/python2.7/site-packages (from django-coverage-plugin==1.4.2)
Requirement already satisfied: coverage>=4.0 in /home/gary/dev/envs/backend/lib/python2.7/site-packages (from django-coverage-plugin==1.4.2)
Requirement already satisfied: six>=1.4.0 in /home/gary/dev/envs/backend/lib/python2.7/site-packages (from django-coverage-plugin==1.4.2)
Installing collected packages: django-coverage-plugin
  Running setup.py install for django-coverage-plugin ... done
Successfully installed django-coverage-plugin-1.4.2
(backend) [9:13:54] gary:backend git:(dev*) $ pip freeze | grep coverage
coverage==4.3.4
django-coverage-plugin==1.4.2
(backend) [9:14:00] gary:backend git:(dev*) $ pip freeze | grep Django
Django==1.9
(backend) [9:11:11] gary:backend git:(dev*) $ coverage run ./manage.py test v4.test.test_scheduler -v 2
Creating test database for alias 'default' 

Thanks for all the hard work.

[PamelaM]

Excellent! Thanks for checking!