Django multi-table inheritance chokes on leaked variable in model definition

Django multi-table inheritance chokes on leaked variable in model definition

class Parent(models.Model):
pass
class RebelliousChild(Parent):
parent_fields = [__x.name for __x in Parent._meta._fields()]
Django 1.3 responds:
django.core.exceptions.FieldError: Local field '_RebelliousChild__x'
in class 'RebelliousChild'clashes with field of similar name from base
class 'Parent'
Django 1.5 responds:
FieldError: Local field u'id' in class 'RebelliousChild' clashes with field
of similar name from base class 'Parent'
My second reaction (after trying to make the variable private) was to
delete the variable (which worked.)
parent_fields = [__x.name for __x in Parent._meta._fields()]
del __x



List comprehensions leak their control variables in Python 2. Django
prohibits overriding parent field attributes, which seems to be involved
somehow, since Django 1.5 has the same issue. But in both cases the leaked
attribute name _RebelliousChild__x isn't defined on Parent.
What is going on here?