makemigrations and regexvalidators

[leftmoose]

comparing RegexValidators doesn't quite work as expected, since it compares compiled instances

not sure why manage.py makemigrations still works (maybe re cache?), but the issue arises if e.g. using call_command(makemigrations)

cat app/models.py
from django.core import validators
from django.db import models


# Create your models here.
class MyModel(models.Model):
    field = models.CharField(
        max_length=1,
        validators=[validators.RegexValidator('[A-Za-z]')],
    )

(single shell session, no changes in the background)

In [1]: from django.core.management import call_command

In [2]: call_command('makemigrations')
Migrations for 'app':
  0001_initial.py:
    - Create model MyModel

In [3]: call_command('makemigrations')
Migrations for 'app':
  0002_auto_20140506_2031.py:
    - Alter field field on mymodel

In [4]: call_command('makemigrations')
Migrations for 'app':
  0003_auto_20140506_2032.py:
    - Alter field field on mymodel

In [5]: call_command('makemigrations')
Migrations for 'app':
  0004_auto_20140506_2032.py:
    - Alter field field on mymodel

[leftmoose]

​https://github.com/django/django/pull/2637

[Andrew Godwin]

This is a duplicate of the issue in #21638, and I've verified that on master it works as expected (I suspect, leftmoose, you're using the beta, where this wasn't fixed yet). Closing as WORKSFORME.

[leftmoose]

@andrewgodwin, if you look at my patch, it sits on top of the fix from #21638. this is not a duplicate. ​a68f32579145dfbd51d87e14f9b5e04c770f9081 compares regex pattern objects, which i change to comparing their parameters. since a68f325 the regex validator has also grown an inverse_match argument, which is ignored. finally, you added __eq__, but no __ne__ which means assertNotEquals don't work properly. please see the pr above

[David Szotten <davidszotten@…>]

In 724a7bf222e31f42e2ab431cc09da224081d03fa:

[1.7.x] Fixed #22588 -- Fix RegexValidator eq

Compare parameters instead of re.pattern instances, and add the other
parameters to the comparison. Also add a ne to make assertNotEqual
work properly.

[Andrew Godwin <andrew@…>]

In d2e96b5792367af5aa0140f7e2673d654bb266df:

Merge pull request #2637 from davidszotten/validator_comparisons

[1.7.x] Fixed #22588 -- Fix RegexValidator eq

[Andrew Godwin <andrew@…>]

In 7fe60ae64ad712430bce26af7812ed4452a91af0:

Fixed #22588 -- Fix RegexValidator eq

Compare parameters instead of re.pattern instances, and add the other
parameters to the comparison. Also add a ne to make assertNotEqual
work properly.

[Andrew Godwin]

Sorry, my bad - we've had the "validators don't compare properly" reopened multiple times recently with people using the beta rather than master. A more descriptive title might have helped, though :)

I've merged in the PR and forward-ported it to master. Let me know if you see anything else wrong.