Remove source map references

[adamchainz]

As reported here: https://code.djangoproject.com/ticket/33353#comment:15

The new CSS source map support in Django 4.1 blocks collectstatic with ManifestStaticFilesStorage with DRF, since it includes CSS files that have source map references but not the source maps themselves.

[donkirkby]

Steps to reproduce:

$ pip install django==4.1 djangorestframework==3.13.1
Collecting django==4.1
  Using cached Django-4.1-py3-none-any.whl (8.1 MB)
Collecting djangorestframework==3.13.1
  Using cached djangorestframework-3.13.1-py3-none-any.whl (958 kB)
Collecting asgiref<4,>=3.5.2
  Using cached asgiref-3.5.2-py3-none-any.whl (22 kB)
Collecting sqlparse>=0.2.2
  Using cached sqlparse-0.4.2-py3-none-any.whl (42 kB)
Collecting pytz
  Using cached pytz-2022.1-py2.py3-none-any.whl (503 kB)
Installing collected packages: pytz, sqlparse, asgiref, django, djangorestframework
Successfully installed asgiref-3.5.2 django-4.1 djangorestframework-3.13.1 pytz-2022.1 sqlparse-0.4.2
$ django-admin startproject mysite
$ cd mysite
$ echo "STATIC_ROOT = 'static_root'" >> mysite/settings.py
$ echo "STATICFILES_STORAGE = 'django.contrib.staticfiles.storage.ManifestStaticFilesStorage'" >> mysite/settings.py
$ echo "INSTALLED_APPS.append('rest_framework')" >> mysite/settings.py
$ python manage.py collectstatic --no-input
Post-processing 'rest_framework/css/bootstrap-theme.min.css' failed!

Traceback (most recent call last):
  File "/home/don/Documents/django_test/mysite/manage.py", line 22, in <module>
    main()
  File "/home/don/Documents/django_test/mysite/manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/core/management/__init__.py", line 446, in execute_from_command_line
    utility.execute()
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/core/management/__init__.py", line 440, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/core/management/base.py", line 402, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/core/management/base.py", line 448, in execute
    output = self.handle(*args, **options)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 209, in handle
    collected = self.collect()
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 154, in collect
    raise processed
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/storage.py", line 338, in _post_process
    content = pattern.sub(converter, content)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/storage.py", line 215, in converter
    hashed_url = self._url(
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/storage.py", line 152, in _url
    hashed_name = hashed_name_func(*args)
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/storage.py", line 388, in _stored_name
    cache_name = self.clean_name(self.hashed_name(name))
  File "/home/don/Documents/django_test/venv_test/lib/python3.9/site-packages/django/contrib/staticfiles/storage.py", line 113, in hashed_name
    raise ValueError(
ValueError: The file 'rest_framework/css/bootstrap-theme.min.css.map' could not be found with <django.contrib.staticfiles.storage.ManifestStaticFilesStorage object at 0x7fdf21937b50>.
$ 

I tried removing the sourceMappingURL lines from bootstrap-theme.min.css and bootstrap.min.css, and that fixed the problem.

[adamchainz]

Great, if you find time, could you make a PR to remove those lines, or to add the source map files to the repo?

[donkirkby]

I decided to remove the lines, instead of adding the source map files.

[lovelydinosaur]

I decided to remove the lines, instead of adding the source map files.

Hrm. Removing parts of a minified CSS seems too easily broken in future changes.
What change would we need to make if we wanted to instead add the source map files?

[adamchainz]

I just downloaded bootstrap 3.4.1 and it comes with the source map files:

It would just be a case of adding them in the repo. It seems in the past they've been deleted / not copied in.

[adamchainz]

I put up an alternate PR, #8591.