I recently ran into an issue when trying to generate an image of my project's models using django_extension's graph_models command. Unfortunately, googling for the error didn't turn up any solutions, so I'm dumping some info here (just in case!).
some background
For the record, I was using django_extensions, version 1.2.5 (the latest release as of this post), and Django 1.4.2 (yeah... it's old)
Running the following command:
$ ./manage.py graph_models my_app > my_models.dot
Gave me the following error
Traceback (most recent call last):
File "./manage.py", line 10, in
execute\_from\_command\_line(sys.argv)
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django/core/management/\_\_init\_\_.py", line 443, in execute\_from\_command\_line
utility.execute()
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django/core/management/\_\_init\_\_.py", line 382, in execute
self.fetch\_command(subcommand).run\_from\_argv(self.argv)
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run\_from\_argv
self.execute(\*args, \*\*options.\_\_dict\_\_)
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
output = self.handle(\*args, \*\*options)
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django\_extensions/management/commands/graph\_models.py", line 72, in handle
dotdata = generate\_dot(args, cli\_options=cli\_options, \*\*options)
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django\_extensions/management/modelviz.py", line 168, in generate\_dot
if field == pk:
File "/home/vagrant/.virtualenvs/my\_app/local/lib/python2.7/site-packages/django/db/models/fields/\_\_init\_\_.py", line 128, in \_\_cmp\_\_
return cmp(self.creation\_counter, other.creation\_counter)
AttributeError: 'NoneType' object has no attribute 'creation\_counter'
The problem?
I'm not entirely sure, but it seems related to this issue.
The solution
Rather, the solution that worked for me (YMMV): Uninstall your current version:
pip uninstall django-extensions
Then install the current development version from github:
pip install -e git+https://github.com/django-extensions/django-extensions.git#egg=django_extensions
Hope that helps someone else!