Opened 15 years ago
Closed 12 years ago
#13075 closed Bug (wontfix)
BaseForm __init__ doesn't super and so breaks MI Mixins
Reported by: | gbauer | Owned by: | nobody |
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Component: | Forms | Version: | 1.1 |
Severity: | Normal | Keywords: | mixins |
Cc: | me@…, Łukasz Rekucki | Triage Stage: | Design decision needed |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
BaseForm's init method doesn't do a super(...) call to follow up the chain, which breaks writing mixins for ModelForms, as the chain is not followed to the classes to the right of the base classes:
class MyForm(ModelForm, ModelFormMixin):
... do stuff
Inheritance will follow ModelForm up the chain until it hits BaseForm and then stop following up further, but ModelFormMixin is in the mro after the mro of ModelForm and so will never looked at. Just adding a super(BaseForm, self).init(.....) to the BaseForm init will work wonders there ...
Change History (10)
comment:1 by , 15 years ago
Triage Stage: | Unreviewed → Accepted |
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comment:2 by , 14 years ago
comment:3 by , 14 years ago
Cc: | added |
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We could choose a class-based generic views way: add a self.args/self.kwargs parameter (or self._args/self._kwargs maybe)
comment:4 by , 14 years ago
Triage Stage: | Accepted → Design decision needed |
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comment:5 by , 14 years ago
Cc: | added |
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I would vote for "won't fix" on this. The proper way to write this is:
class MyForm(ModelFormMixin, ModelForm): pass
I don't see a reason why a mixin should be later in MRO then the class it extends. If the mixin is unrelated to ModelForm then putting it in front won't hurt either. This is also how class-based views use mixins.
comment:6 by , 14 years ago
Severity: | → Normal |
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comment:7 by , 13 years ago
Type: | → Bug |
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This is a bit harder than it looks at first sight. According to http://fuhm.net/super-harmful/ , every single argument should be passed on. However, this obviously won't work when there aren't any mixins around, just object, because object does not accept any arguments in init.
On the other hand, standard subclassing of Form expects all arguments BaseForm itself accepts too.
Depending on the mro, mixins/subclasses will have to accept either *args/kwargs or nothing.
I'm not sure how we should fix this issue.