#13460: django.db.models.Model breaks multiple inheritance
----------------------------+-----------------------------------------------
Reporter: Art_S | Owner: nobody
Status: new | Milestone:
Component: Core framework | Version: 1.1
Keywords: inheritance | Stage: Unreviewed
Has_patch: 0 |
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django.db.models.Model breaks multiple inheritance by not calling
super(...).__init__(...)
Here's example code:
{{{
from django.db import models
class A(models.Model):
def __init__(self, *args, **kwargs):
super(A, self).__init__(*args, **kwargs)
print 'A'
m = models.CharField()
class B(object):
def __init__(self, *args, **kwargs):
super(B, self).__init__(*args, **kwargs)
print 'B'
class C(object):
def __init__(self, *args, **kwargs):
super(C, self).__init__(*args, **kwargs)
print 'C'
class D(A, B, C):
def __init__(self, *args, **kwargs):
super(D, self).__init__(*args, **kwargs)
print 'D'
D()
}}}
Resulting in:
{{{
A
D
}}}
However as soon as I remove models.Model from parent for A and replace it
with 'object', all the constructors are getting called and the output is:
{{{
C
B
A
D
}}}
Apparently this happens because MRO is nto beign composed properly when
you ommit calls to parent's __init__, even if it's the object.
See http://fuhm.net/super-harmful/ for more details.
--
Ticket URL: <http://code.djangoproject.com/ticket/13460>
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