Django migrations for Mezzanine EXTRA_MODEL_FIELD

0001_form_add_field.py

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations
import mezzanine.core.fields


class AddExtraField(migrations.AddField):

    def __init__(self, *args, **kwargs):
        if 'app_label' in kwargs:
            self.app_label = kwargs.pop('app_label')
        else:
            self.app_label = None
        super(AddExtraField, self).__init__(*args, **kwargs)

    def state_forwards(self, app_label, state):
        super(AddExtraField, self).state_forwards(self.app_label or app_label, state)

    def database_forwards(self, app_label, schema_editor, from_state, to_state):
        super(AddExtraField, self).database_forwards(
            self.app_label or app_label, schema_editor, from_state, to_state)

    def database_backwards(self, app_label, schema_editor, from_state, to_state):
        super(AddExtraField, self).database_backwards(
            self.app_label or app_label, schema_editor, from_state, to_state)


class Migration(migrations.Migration):

    dependencies = [
        ('forms', '0004_auto_20150517_0510'),
    ]

    operations = [
        AddExtraField(
            model_name='form',
            name='heading',
            field=models.CharField(max_length=400, verbose_name='Heading', blank=True),
            app_label='forms'
        ),
    ]

settings.py

# ...
EXTRA_MODEL_FIELDS = (
    (
        "mezzanine.forms.models.Form.heading",
        "CharField", # 'django.db.models.' is implied if path is omitted.
        ("Heading",),
        {'max_length': 400, 'blank': True},
    ),
)
# ...