Static file error with heroku

[cxrodgers]

Hi, I'd like to use nested_inline on a django instance running on heroku. Everything works great locally, but I'm getting an error on the heroku server, for some reason.

I followed the heroku guide to getting a minimal django setup working:
https://devcenter.heroku.com/articles/getting-started-with-python#introduction
So far, so good.

Then I added "django-nested-inline" to my requirements.txt, added 'nested_inline' to the end of my INSTALLED_APPS, and "from nested_inline.admin import NestedModelAdmin, NestedStackedInline" to my admin.py.

Everything still works perfectly locally, with no issues. But when I push to heroku "git push heroku master", I get the following error:
git push heroku master
Counting objects: 7, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (7/7), done.
Writing objects: 100% (7/7), 670 bytes | 0 bytes/s, done.
Total 7 (delta 5), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Python app detected
remote: $ pip install -r requirements.txt
remote: Collecting django-nested-inline (from -r requirements.txt (line 6))
remote: Downloading django-nested-inline-0.3.6.tar.gz
remote: Installing collected packages: django-nested-inline
remote: Running setup.py install for django-nested-inline: started
remote: Running setup.py install for django-nested-inline: finished with status 'done'
remote: Successfully installed django-nested-inline-0.3.6
remote:
remote: $ python manage.py collectstatic --noinput
remote: Post-processing 'admin/css/forms-nested.css' failed!
remote: Traceback (most recent call last):
remote: File "manage.py", line 10, in
remote: execute_from_command_line(sys.argv)
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/init.py", line 353, in execute_from_command_line
remote: utility.execute()
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/init.py", line 345, in execute
remote: self.fetch_command(subcommand).run_from_argv(self.argv)
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
remote: self.execute(_args, *_cmd_options)
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
remote: output = self.handle(_args, *_options)
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 176, in handle
remote: collected = self.collect()
remote: File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 128, in collect
remote: raise processed
remote: whitenoise.django.MissingFileError: The file 'admin/img/nav-bg.gif' could not be found with <whitenoise.django.GzipManifestStaticFilesStorage object at 0x7f23006c2910>.
remote: The CSS file 'admin/css/forms-nested.css' references a file which could not be found:
remote: admin/img/nav-bg.gif
remote: Please check the URL references in this CSS file, particularly any
remote: relative paths which might be pointing to the wrong location.
remote:
remote: ! Error while running '$ python manage.py collectstatic --noinput'.
remote: See traceback above for details.
remote:
remote: You may need to update application code to resolve this error.
remote: Or, you can disable collectstatic for this application:
remote:
remote: $ heroku config:set DISABLE_COLLECTSTATIC=1
remote:
remote: https://devcenter.heroku.com/articles/django-assets

I'm confused about why it's working differently on heroku than locally. Also, I can't find that nav-bg.gif file anywhere, but this doesn't stop nested_inline from working locally. Thanks for any tips! I realize this may be a heroku-specific issue, but I thought posting here would be more likely to reach someone who can identify the problem.

[cxrodgers]

I think I see what the problem is. There is no "img" directory in nested_inline/static/admin/ in this repository, yet many lines of forms_nested.css refer to it. Maybe they were inadvertently left out of source control? Previous versions of django or whitenoise may have silently ignored missing files, but now they raise exceptions. I fixed it by simply removing every line of forms_nested.css that refers to ../img. I created a fork on my own github page so that I can add it to my requirements.txt with heroku.
git+git://github.com/cxrodgers/django-nested-inline.git

[smcoll]

OK, it looks like that was an image which used to exist in Django. The other images are included still available in Django's static media, but as svg. See this commit: django/django@35901e6

So, really what is needed is support for the new Django admin theme.