contentypes generic module has core functionality plus admins-specific one

[Ramiro Morales]

(Copied and adapted from https://code.djangoproject.com/ticket/16368#comment:16)

Consider a project with a foo and a bar apps listed on INSTALLED_APPS:

• foo uses generic foreign keys, with the following models.py:

  from django.db import models
  from django.contrib.contenttypes.models import ContentType
  from django.contrib.contenttypes import generic
  
  class TaggedItem(models.Model):
      tag = models.SlugField()
      content_type = models.ForeignKey(ContentType)
      object_id = models.PositiveIntegerField()
      content_object = generic.GenericForeignKey()
  

• bar has a Site model:

  from django.db import models
  
  class Site(models.Model):
      name = models.CharField(...
      # ...
  

• Neither the admin nor sites Django apps are being used.

This causes the user's Site model to be overridden and masked by Django sites framework's one.

This is because the django/contrib/contenttypes/generic.py module contain both the definitions of the model-related generic stuff (GenericForeignKey, etc.) AND the admin app-related specialized inlines (GenericInlineModelAdmin, GenericStackedInline, GenericTabularInline.)

Maybe it's time we move the latter ones from django.contrib.contenttypes.generic to, say, a new generic_admin (or admin_tools?) on django.contrib.contenttypes?. Of course this would need a deprecation process.