Define strict return value typing for Depends and Security #11255
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JaniM
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I think it's a good fix!
I would only change the title and description to make things clearer.
In fact, this fix does not cause FastAPI to show any errors if the returned dependency type does not match the parameter type. But this fix allows you to find this error using mypy.
With this fix, 'mypy' will show error: Incompatible default for argument "value" (default has type "str", argument has type "int") [assignment].
UPD: why don't you add the same to the Security as well?
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I didn't touch Edit: Made the change. |
JaniM
changed the title
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The checks seem to be stuck, can someone give them a nudge? |
Depends can be used with a direct form, which although not recommended, is
still supported. The following code is problematic wrt. type checking.
def dependency() -> str:
return "dependency"
@router.get("/")
def endpoint(value: int = Depends(dependency)):
pass
Currently, `Depends(dependency)` returns Any, which then happily gets assigned
to the int. This patch changes it to return a type matching what the dependency
returns, making the above code fail type checking with mypy as it should.
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Good fix! Hoping this gets merged soon... |
Depends can be used with a direct form, which although not recommended, is still supported. The following code is problematic wrt. type checking.
Currently,
Depends(dependency)returns Any, which then happily gets assigned to the int. This patch changes it to return a type matching what the dependency returns, making the above code fail type checking with mypy as it should.