Pipenv install djangorestframework does not install pytz

[Eduardo-RFarias]

I'm having an issue when installing django rest framework using pipenv, the required lib Pytz is not being installed in my venv.

• I first noticed this error with github actions and I could temporally fix it by running pip install pytz in the workflow.

• The traceback:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    main()
  File "manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/__init__.py", line 425, in execute_from_command_line
    utility.execute()
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/__init__.py", line 419, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/commands/test.py", line 24, in run_from_argv
    super().run_from_argv(argv)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/base.py", line 373, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/base.py", line 417, in execute
    output = self.handle(*args, **options)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/commands/test.py", line 59, in handle
    failures = test_runner.run_tests(test_labels)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/test/runner.py", line 933, in run_tests
    self.run_checks(databases)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/test/runner.py", line 852, in run_checks
    call_command('check', verbosity=self.verbosity, databases=databases)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/__init__.py", line 187, in call_command
    return command.execute(*args, **defaults)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/base.py", line 417, in execute
    output = self.handle(*args, **options)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/commands/check.py", line 63, in handle
    self.check(
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/management/base.py", line 438, in check
    all_issues = checks.run_checks(
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/core/checks/registry.py", line 77, in run_checks
    new_errors = check(app_configs=app_configs, databases=databases)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/contrib/admin/checks.py", line 78, in check_dependencies
    for engine in engines.all():
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/utils.py", line 90, in all
    return [self[alias] for alias in self]
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/utils.py", line 90, in <listcomp>
    return [self[alias] for alias in self]
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/utils.py", line 81, in __getitem__
    engine = engine_cls(params)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/backends/django.py", line 25, in __init__
    options['libraries'] = self.get_templatetag_libraries(libraries)
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/backends/django.py", line 43, in get_templatetag_libraries
    libraries = get_installed_libraries()
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/backends/django.py", line 108, in get_installed_libraries
    for name in get_package_libraries(pkg):
  File "/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/django/template/backends/django.py", line 123, in get_package_libraries
    raise InvalidTemplateLibrary(
django.template.library.InvalidTemplateLibrary: Invalid template library specified. ImportError raised when trying to load 'rest_framework.templatetags.rest_framework': No module named 'pytz' 

• Here's my pipfile:

I don't know if this is a problem with pipenv or djangorestframework installer, could you help me fix this without manually installing it with pip?

[tomchristie]

What versions of Django and Django REST framework are you using when seeing this error?

[Eduardo-RFarias]

I'll just downgrade django then, thanks for solving this for me.

[hannseman]

We can figure out a workaround in REST framework, but for now you'll need to just install that directly.

@tomchristie, AFAIK this is already fixed by #8178, maybe it’s just a matter of issuing a new release?

cc @carltongibson

[tomchristie]

I don't think so, no. It looks like we've got at least one or two places internally that still happen to import the pytz package. Presumably our CI happens to install it anyways, so it's passing for us.

[hannseman]

Wouldn't the addition of pytz to install_requires in #8178 handle that? If I understand correctly there was some issues in that PR which prevented removing pytz altogether which required the addition of it to install_requires until we can work it out.

[carltongibson]

The serialiser DateTime fields use pytz internally still. Adding pytz to install_requires makes sure pytz is available, so I think a new release would be enough for minimal compatibility.

Beyond that, use the pytz deprecation shim, and/or the transitional USE_DEPRECATED_PYTZ setting may be needed, but I'm waiting to see the actual issues that arise.

Pending a new DRF release, this issue can be worked around (exactly) with a pip install pytz somewhere.

[carltongibson]

I've pinned this discussion for now, as I guess folks'll bump into it.

The solution is to rework the couple of pytz uses to be tzinfo implementation agnostic.

[rmaleki]

remove dependency on pytz

#8984