Breaking running of coverage when enabled

First, thanks for this great plug-in! I’ve found it quite useful for testing some of the logic in my templates. 👍

I know this used to work in my project, but I’m not sure when it broke. (I don’t think this has updated in a while, it could have been a Django update that broke this?)

My project is using Django 1.10.4, coverage 4.3.1, django-coverage-plugin 1.3.1. (I also tried with coverage 4.2, that exhibited the same behavior.)

While running with this I’m getting a stack trace:

/vagrant$ coverage run manage.py test
Coverage.py warning: Disabling plugin 'django_coverage_plugin.DjangoTemplatePlugin' due to an exception:
Traceback (most recent call last):
  File "/usr/local/venv/local/lib/python2.7/site-packages/coverage/control.py", line 497, in _should_trace_internal
    file_tracer = plugin.file_tracer(canonical)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 154, in file_tracer
    check_debug()
  File "/usr/local/venv/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py", line 55, in check_debug
    templates = getattr(settings, 'TEMPLATES', [])
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 53, in __getattr__
    self._setup(name)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 41, in _setup
    self._wrapped = Settings(settings_module)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 97, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/vagrant/my_project/settings.py", line 8, in <module>
    from django.contrib.messages import constants as message_constants
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/contrib/messages/__init__.py", line 1, in <module>
    from django.contrib.messages.api import *  # NOQA
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/contrib/messages/api.py", line 3, in <module>
    from django.http import HttpRequest
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/http/__init__.py", line 5, in <module>
    from django.http.response import (
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/http/response.py", line 13, in <module>
    from django.core.serializers.json import DjangoJSONEncoder
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/core/serializers/__init__.py", line 23, in <module>
    from django.core.serializers.base import SerializerDoesNotExist
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/core/serializers/base.py", line 4, in <module>
    from django.db import models
ImportError: cannot import name models
Traceback (most recent call last):
  File "manage.py", line 45, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 316, in execute
    settings.INSTALLED_APPS
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 53, in __getattr__
    self._setup(name)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 41, in _setup
    self._wrapped = Settings(settings_module)
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/conf/__init__.py", line 97, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/vagrant/my_project/settings.py", line 8, in <module>
    from django.contrib.messages import constants as message_constants
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/contrib/messages/__init__.py", line 1, in <module>
    from django.contrib.messages.api import *  # NOQA
  File "/usr/local/venv/local/lib/python2.7/site-packages/django/contrib/messages/api.py", line 1, in <module>
    from django.contrib.messages import constants
ImportError: cannot import name constants

This seems to be because I’m importing django.contrib.messages.constants in my settings file, note that if I remove this line I get other errors about importing. This seems related to loading of Django settings before Django is configured (see https://github.com/nedbat/django_coverage_plugin/issues/28#issuecomment-243723099), but with much worse consequences.

Let me know if there is anything I can do to help confirm my suspicion or narrow this down! Thanks.

[PamelaM]

Hi, this is a chicken-and-egg problem with settings configuration-and template loading that I think is masked by the the django_coverage_plugin test environment (initialization order stuff is always hard to test).

I’ve got a reproducible case and I’m working on it - but it’s prioritized behind a couple of other commitments. Hopefully this weekend for a fix to this problem and later I’ll update the dj-c-p test framework to include a stand-alone test_project to provide for some cleaner integration tests.

pam

On Tue, Jan 17, 2017 at 9:49 AM, Patrick Cloke [e-mail] wrote:

@PamelaM https://github.com/PamelaM First, thanks for taking a look at this! 👍

This seems to have fixed the issue of coverage erroring immediately when running, but unfortunately I don’t seem to have any coverage of the templates! (I can run coverage and get a coverage report, including the template files, but it doesn’t seem to have actually processed these files.)

I’m getting the following warning when I run coverage:

coverage run manage.py test Coverage.py warning: Disabling plugin ‘django_coverage_plugin.DjangoTemplatePlugin’ due to an exception: Traceback (most recent call last): File “/usr/local/venv/local/lib/python2.7/site-packages/coverage/control.py”, line 476, in _should_trace_internal file_tracer = plugin.file_tracer(canonical) File “/usr/local/venv/local/lib/python2.7/site-packages/django_coverage_plugin/plugin.py”, line 158, in file_tracer self.debug_checked = check_debug() File “/usr/local/venv/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’

I tried this quickly in a Django shell and django.template DOES have an attribute backends. My settings look like:

TEMPLATES = [ { ‘BACKEND’: ‘django.template.backends.django.DjangoTemplates’, ‘DIRS’: [normpath(join(DJANGO_ROOT, ‘templates’))], ‘APP_DIRS’: True, ‘OPTIONS’: { ‘context_processors’: [ ‘django.contrib.auth.context_processors.auth’, ‘django.template.context_processors.debug’, ‘django.template.context_processors.i18n’, ‘django.template.context_processors.media’, ‘django.template.context_processors.static’, ‘django.template.context_processors.tz’, ‘django.contrib.messages.context_processors.messages’, ‘django.template.context_processors.request’,

            # + a few custom ones.
        ],
        'debug': DEBUG,
    },
},

]

Any idea what’s happening here? Thanks again!

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[clokep]

💥 That worked! Seems like this was fixed by #33. Thanks so much for the help!