FileFields can't be set to NULL in the db

[oyvind]

Hi,

[oyvind]

Patch does not seem to work quite like I expected. So the problem persists.

[oyvind]

Example to test this issue:

                
class File(models.Model):

    file = models.FileField(null=True, upload_to='files') 

from models import File

f = File()
f.file = None
f.save()

from django.db import connection
print connection.queries

[oyvind]

Patch that solves this issue, FieldFile's name can now be None also "is" and "==" is not the same

[Alex Gaynor]

needs to be decided whether the CharField behavior should be used throughout, or NULL where explicitly requested

[oyvind]

Meade FieldFile set name to u on delete, made test show filefields and charfields act the same

[Karen Tracey]

Dev list discussion: ​http://groups.google.com/group/django-developers/browse_thread/thread/cf37abc95e49f0e/

Also, #10749 reported surprise at searching for None not working when looking for empty ImageFields. I still think changing this now breaks backwards-compatibility, though.

[Aymeric Augustin]

I see two possible solutions:

• 1. document that FileField ignores the null keyword argument; this is the most backwards compatible solution;
• 2. make FileField behave exactly like CharField wrt. null; this is the most consistent solution.

Option 2. will be backwards incompatible only for people who set null=True on a FileField. The docs discourage that heavily, and it doesn't behave as expected, actually it doesn't even do anything, so there isn't much reason to have such code. That's why I think the change would be acceptable.

I have a slight preference for option 2, which is better in the long term.

[siroky@…]

Hi! What is the status of this ticket? I see it is 5 years old ticket and the problem is still present at least in 1.5.1.

[Aymeric Augustin]

It's waiting for someone to write a patch.

[siroky@…]

None/NULL for FileField (v1.5.1)

[siroky@…]

How about the filefield_null.patch? It follows solution 2.

[Claude Paroz]

Thanks, it's a first step :-) However, tests are crucial with such a change. That will be the next step. See FileFieldTestsin tests/model_fields/tests.py.

[anonymous]

How can I run the FileFieldTests without the whole suite?

[Tim Graham]

See ​https://docs.djangoproject.com/en/dev/internals/contributing/writing-code/unit-tests/#running-only-some-of-the-tests

[siroky@…]

I bumped into a problem. If instance.null_file_field is None then methods like save() will not work (AttributeError: 'NoneType' object has no attribute 'save'). I'm thinking about 2 solutions:
1) Make the descriptor return value comparable to None (via __eq__). This is not very clean because the best practise is to use operator is (is_none = x is None).
2) Keep the empty string ("") on the Python side as a representation of file's database NULL. Not very consistent but it has better backward compatibility if someone already uses the string comparison (has_no_file = filefield.name == "").

Any suggestions?

[Claude Paroz]

#25528 was a duplicate.

[Raffaele Salmaso]

Hi all, what is the status of this ticket?
FileField behaviour is not really clear right now and flake8-django just made a change to allow FileField(null=True) (see ​https://github.com/rocioar/flake8-django/issues/82), which seems wrong to me.

I'm for option 2 make FileField behave exactly like CharField wrt. null.