Opened 5 days ago
Last modified 4 days ago
#35827 new New feature
Model subclass with __init_subclass__ doesn't get correct _meta instance — at Version 4
Reported by: | Ben Beecher | Owned by: | |
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Component: | Database layer (models, ORM) | Version: | 5.0 |
Severity: | Normal | Keywords: | |
Cc: | Triage Stage: | Someday/Maybe | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
When defining and using a model mixin like so:
class ModelMixin(Model): class Meta: abstract = True def __init_subclass__(cls) -> None: super().__init_subclass__() breakpoint() cls._my_setup_func() class TestModel(ModelMixin): name = models.CharField(max_length=100)
The init_subclass call will be first called when the class is created here:
https://github.com/django/django/blob/main/django/db/models/base.py#L120
However the meta is attached here:
https://github.com/django/django/blob/main/django/db/models/base.py#L143
So during the init_subclass call you will have the superclass' meta object if you try to access it.
55 def __init_subclass__(cls) -> None: 56 super().__init_subclass__() 57 breakpoint() 58 -> cls._my_setup_func() (Pdb++) cls <class 'label.TestModel'> (Pdb++) cls._meta <Options for ModelMixin>
Change History (4)
comment:1 by , 5 days ago
Description: | modified (diff) |
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comment:2 by , 5 days ago
Description: | modified (diff) |
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comment:3 by , 5 days ago
Description: | modified (diff) |
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comment:4 by , 5 days ago
Description: | modified (diff) |
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