Support for Django 1.7b4

[bh]

Hi,
could you please add support for Django >= 1.7. I get the following error:

TypeError: Couldn't reconstruct field gender on webapp.MxUser: __init__() missing 1 required positional argument: 'enum'

.. when running:

$ python manage.py makemigrations

Thank you!

[samh]

Fixed by 7b4c20b

[bh]

Does not work:

class FooModel(modelsModels):
    class Gender(Enum):
        MALE = "m"
        FEMALE = "f"
        UNKNOWN = "u"

        class Labels:
            MALE = 'Male',
            FEMALE = 'Female',
            UNKNOWN = 'Unknown'

    gender = EnumField(Gender, max_length=1, blank=True, null=True)

python manage.py makemigrations returns:

  File "/home/bhe/.virtualenvs/mx-py34/lib/python3.4/site-packages/django/db/migrations/writer.py", line 349, in serialize
    raise ValueError("Cannot serialize: %r\nThere are some values Django cannot serialize into migration files.\nFor more, see https://docs.djangoproject.com/en/dev/topics/migrations/#migration-serializing" % value)
ValueError: Cannot serialize: <Gender.MALE: 'm'>
There are some values Django cannot serialize into migration files.
For more, see https://docs.djangoproject.com/en/dev/topics/migrations/#migration-serializing

[samh]

I see; I hadn't actually tried migrations (just got it to work with unmigrated models).

I was able to get it working by adding a deconstruct method in the init method like so:

def __init__(self, value):
    def deconstruct():
        return (
            '%s.%s' % (self.__class__.__module__, self.__class__.__name__),
            (self.value,),
            {}
        )
    self.deconstruct = deconstruct

A standard deconstruct method fails because Django tries to call it on the type, not just the instances. I think this might be considered a Django bug, so I haven't yet made a pull request here. If I've missed something, I'm open to suggestions.

I would also remove 'choices' in the deconstruct method in EnumFieldMixin, since it should be generated from the enum:

kwargs.pop('choices', None)

[bh]

There could occur another issue with nested classes.

class FooModel(models.Model):
    class Gender(Enum):
        MALE = "m"
        FEMALE = "f"
        UNKNOWN = "u"
    g = EnumFIeld(Gender)

vs.

class Gender(Enum):
    MALE = "m"
    FEMALE = "f"
    UNKNOWN = "u"

class FooModel(models.Model):
    g = EnumFIeld(Gender)

Something like (self.__class__.__module__, self.__class__.__name__), cannot be used with nested classes, I think. Because the Django migration engine cannot import a class from another one.

[samh]

Related Django bug: https://code.djangoproject.com/ticket/22951

[matthewwithanm]

@bh @samh Sorry this went under the radar ):

I just pushed 0.5.1 which removes choices from the deconstructed kwargs. I think we can get around the nested class issue by improving our handling of the string case and having deconstruct() always use a string.