Set minimum Django version in setup.py

[threehundred]

Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python2.7/site-packages/rest_framework_filters/init.py", line 3, in
from .filterset import FilterSet
File "/usr/local/lib/python2.7/site-packages/rest_framework_filters/filterset.py", line 13, in
from django_filters import filterset
File "/usr/local/lib/python2.7/site-packages/django_filters/init.py", line 3, in
from .filterset import FilterSet
File "/usr/local/lib/python2.7/site-packages/django_filters/filterset.py", line 19, in
from .filters import (Filter, CharFilter, BooleanFilter, BaseInFilter, BaseRangeFilter,
File "/usr/local/lib/python2.7/site-packages/django_filters/filters.py", line 16, in
from .fields import (
File "/usr/local/lib/python2.7/site-packages/django_filters/fields.py", line 13, in
from .utils import handle_timezone
File "/usr/local/lib/python2.7/site-packages/django_filters/utils.py", line 4, in
from django.db.models.expressions import Expression
ImportError: cannot import name Expression

Just an FYI - I couldn't find any django version restrictions in your release notes.

Cheers.

[threehundred]

Sorry went back through history - I see you've dropped support for 1.7, will close.

[philipn]

Thanks @threehundred! We should probably restrict the Django version in our setup.py, so I'm re-opening this issue.

[rpkilby]

@philipn I'm kind of wondering what should be done here. A couple of thoughts:

• If we want to specify a minimum Django version, should we or should django-filter do this? ie, we're an extension of django-filter, which is an extension of Django. For all intents and purposes, we have the same compatibility guarantees as django-filter (also notice that the actual error in the trace was thrown from django-filter).
• There is some push to not specify Django in the requires section. See Remove Django itself from install_requires jazzband/django-model-utils#183. In short, it can cause some issues across multiple pip installs.
• A lot of projects don't specify django in the requires. eg, DRF, django-filter

[philipn]

Hmm. You're totally right that few apps seem to list a Django dependency. No strong opinion, but my 2c--

It seems like people should be pinning their version of Django in their project's requirements (and using something sweet like https://github.com/nvie/pip-tools, to boot!) If they did, they'd never have problems like in the linked ticket(s). In the linked ticket, @carljm says "[django] doesn't need any automatic dependency handling", but this kind of issue is exactly why the dependency would help people -- they'd find out there's a problem during installation rather than at run time.

I wonder what kind of problem is more common -- hitting an unknown error during an upgrade because a package hasn't been tested / support has dropped for your version of Django, or having Django automatically upgraded and not wanting that behavior.

[rpkilby]

Thinking back,

• Adding Django as a dependency creates a problem for development environments, not deployments. eg, you would pip install -U djangorestframework-filters to test out the latest changes, and then accidentally update Django itself. Installing from a requirements file should complain about conflicts.
• drf-filters is more an extension of django-filter than it is an extension of Django. The django-filter dependency should be sufficient?
• drf-filters at least supports all currently supported versions of Django. I think the real answer here is "Don't use an outdated and unsupported version of Django".

[rpkilby]

@philipn - Are we agreed that django shouldn't be listed as a requirement? Closing this as it's an easy modification if you decide otherwise.