Change Summary

The primary change of this PR is to allow code as below to work properly:

classA[T](BaseModel):@validate_call(validate_return=True)deff(self,x:T)->T:returnxa=A[int]()asserta.f(1)==1asserta.f('1')==1a.f('abc')# throw error correctly

Limitations

I classify generic functions into three cases:

1. The TypeVar is "free", or attached to a function:

T=TypeVar("T")deff(a:T): ...# ordeff[T](a:T): ...

2. The TypeVar is attached to a class that is not a subclass ofBaseModel:

classA(Generic[T]):deff(a:T): ...# orclassA[T]:deff(a:T): ...

3. The TypeVar is attached to a class thatis a subclass ofBaseModel:

classA(BaseModel,Generic[T]):deff(a:T): ...# orclassA[T](BaseModel):deff(a:T): ...

For the case 1 and 2, there is (AFAIK) unfortunately no way to access the value ofT at runtime without custom__class_getitem__. See theissue anddiscussion. Therefore there is no way to "trigger" the schema rebuilding process.

For case 3, the value ofT is always determined and can be accessed at runtime. Hence, this PR currently only supports such case.

Update: I realize that in case 1, we can override the__getitem__ such that the user can do something likef[int](...) to manually trigger rebuilding. The only problem is thatFunctionType is not allowed to be subclassed, and instance-level method override does not work for dunder methods, so we must return an object whose type is notFunctionType anymore. This seems to conflict with current design.

As for case 2, perhaps we could expose another API, e.g.enable_generic_validate_call, so that when a class is decorated by it, we override its__class_getitem__ and do the similar stuff asBaseModel.

Related issue number

#7796 (partially fixed)

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review,please add a comment including the phrase "please review" to assign reviewers