Model field name 'hiding' should not be permitted when field is defined in one of the parent models

[Vasily Ivanov]

According to ​http://docs.djangoproject.com/en/1.1/topics/db/models/#field-name-hiding-is-not-permitted it is not permitted to hide field name in child
model and django would raise a FieldError exception. And that's
exactly what happens:

class Phone(models.Model):
  pass

class Service(models.Model):
   phone = models.ForeignKey(Phone, related_name='services')

class Call(Service):
   phone = models.ForeignKey(Phone, related_name='calls')

> manage.py validate
django.core.exceptions.FieldError: Local field 'phone' in class 'Call' clashes with field of similar name from base class 'Service'

works as expected... no problem

However, if I add new IntermediateService model like this:

class Phone(models.Model):
  pass

class Service(models.Model):
   phone = models.ForeignKey(Phone, related_name='services')

class IntermediateService(Service):
   class Meta:
       abstract = True

class Call(IntermediateService):
   phone = models.ForeignKey(Phone, related_name='calls')

...surprisingly it validates:

> manage.py validate
0 errors found

and generates sqls for postgresql:

> manage.py sql app

CREATE TABLE "app_phone" (
   "id" serial NOT NULL PRIMARY KEY
);
CREATE TABLE "app_service" (
   "id" serial NOT NULL PRIMARY KEY,
   "phone_id" integer NOT NULL REFERENCES "app_phone" ("id")
DEFERRABLE INITIALLY DEFERRED
);
CREATE TABLE "app_call" (
   "service_ptr_id" integer NOT NULL UNIQUE REFERENCES
"app_service" ("id") DEFERRABLE INITIALLY DEFERRED,
   "phone_id" integer NOT NULL REFERENCES "app_phone" ("id")
DEFERRABLE INITIALLY DEFERRED
);

Looks like a bug to me.

[Russell Keith-Magee]

I'm not completely convinced that the error isn't using an abstract model in the middle of an inheritance chain. However, either way, there is a bug than needs to be resolved.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Tim Graham]

Duplicate of #17673