graphql-python / graphql-python/graphene

Why SubclassWithMeta.__init_subclass__ terminates the super() chain?

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✨ enhancement
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Description

Is there a great reason why `graphene.utils.subclass_with_meta.SubclassWithMeta.__init_subclass__`, doesn't call `super().__init_subclass__()`?
https://github.com/graphql-python/graphene/blob/master/graphene/utils/subclass_with_meta.py#L21-#L46

The issue with this is IMO the following:

- Class `Foo` has defined a custom `__init_subclass__`.
- Class `Bar` derives from `Foo` and e.g. `graphene.types.ObjectType`.

Now if `Foo` is accidentally placed after `ObjectType` in `Bar`'s inheritance list, `Foo.__init_subclass__` will never be run.

Here's a quick demo:

```
from graphene.types import ObjectType

class Foo:
def __init_subclass__(cls):
print(f"Init Foo's subclass: {cls.__name__}")
super().__init_subclass__()

class Bar1(Foo, ObjectType):
pass

class Bar2(ObjectType, Foo):
pass
```

>Output:
>```
>Init Foo's subclass: Bar1
>```

[My proposed fix PR](https://github.com/graphql-python/graphene/pull/1234) would simply add `super().__init_subclass__()` to the last line of `SubclassWithMeta.__init_subclass__`.

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  1. Read the whole issue, then the project's contributing guide.
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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with graphene/utils/subclass_with_meta.py at lines 21-46 and reproduce the Foo, Bar1, and Bar2 example from the issue. Review the proposed fix in graphene/pull/1234 and verify that SubclassWithMeta.__init_subclass__ no longer stops the cooperative super() chain. Done means Foo.__init_subclass__ runs for both inheritance orders without breaking existing behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
25/100

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