Inheritance issue

[romansemko]

I am having problems with simple inheritance.

Here is my models.py:

class BaseSegment(models.Model):
    name = models.CharField(max_length=256, verbose_name=_("Name"), unique=True)

class Segment(BaseSegment):
    label = models.CharField(max_length=256, verbose_name=_("Label"), default='')
    description = models.TextField(verbose_name=_("Description"), default='')

And my translation.py:

from modeltranslation.translator import translator, TranslationOptions
from models import BaseSegment, Segment

class BaseSegmentOptions(TranslationOptions):
    fields = ('name',)

class SegmentOptions(BaseSegmentOptions):
    fields = ('label', 'description')

translator.register(BaseSegment, BaseSegmentOptions)
translator.register(Segment, SegmentOptions)

This does not work, Django (1.8.0) complains when trying to makemigrations:

SystemCheckError: System check identified some issues:

ERRORS:
base.Segment.name_de: (models.E006) The field 'name_de' clashes with the field 'name_de' from model 'base.basesegment'.
base.Segment.name_en: (models.E006) The field 'name_en' clashes with the field 'name_en' from model 'base.basesegment'.
base.Segment.name_fr: (models.E006) The field 'name_fr' clashes with the field 'name_fr' from model 'base.basesegment'.

I have tried just registering the SegmentModel, practically without this line

translator.register(BaseSegment, BaseSegmentOptions)

But then, modeltranslation complains:

modeltranslation.translator.NotRegistered: The model "BaseSegment" is not registered for translation

I have tried skipping BaseSegment alltogether, adding the 'name' field to SegmentOptions, but then the 'name' field seems completely empty (although it is already pre-populated in the 'name' field in BaseSegment).

What am I doing wrong?

[romansemko]

Django v1.8.6 - same behaviour.

[wernight]

I'm having the same issue with normal inheritance, also after upgrading.

[wernight]

Fixed by loading modeltranslation before django.contrib.admin in INSTALLED_APPS.

[SalahAdDin]

Interesting, it will be very useful put that in the documentation.

[zlorf]

Gosh, it's there, just read it carefully: http://django-modeltranslation.readthedocs.org/en/latest/installation.html#required-settings

[zlorf]

@romansemko You need to change SegmentOptions to NOT inherit from BaseSegmentOptions. That's because fields are inherited this way: http://django-modeltranslation.readthedocs.org/en/latest/registration.html#translationoptions-fields-inheritance And SegmentOptions.fields == ('name', 'label', 'description'). But name is the field not on Segment, but on BaseSegment only.

[arpitremarkable]

Just inherit SegmentOptions from TranslationOptions. No other change in your code is required. . It is all a bit un-intuitive at first but you'll figure it out when you go through the codebase. This scenario could have been handled more elegantly though.