CodSpeed Performance Report

Merging#10789 willnot alter performance

_{ComparingFyZzyss:9418-support-equals-bound-and-default (22a2bd4) withmain (0157e34)}

Summary

✅ 44 untouched benchmarks

Coverage report

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File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
pydantic/_internal
_generate_schema.py
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please review

@FyZzyss,

Thanks for your contribution! We'll review this soon - working on pushing v2.10 out now, but I'm anticipating we can get this into v2.11 :)

I think it's safe to support all combinations with bounds, constraints and defaults. In any case, we prioritize the default type overconstraints orbound:

T1=TypeVar('T1',bound=int,default=SubInt)-->generatesaschemafor`SubInt`T2=TypeVar('T2',int,str,default=int)-->generatesaschemafor`int`

Having a different bound and default shouldn't be an issue. The only requirement -- from a static type checking perspective -- is thatdefault should be a subtype ofbound. But such checks are out of scope for Pydantic (see#10462 (comment)).

This should work:

def_unsubstituted_typevar_schema(self,typevar:typing.TypeVar)->core_schema.CoreSchema:try:has_default=typevar.has_default()exceptAttributeError:# Happens if using `typing.TypeVar` on Python < 3.13passelse:ifhas_default:returnself.generate_schema(typevar.__default__)# pyright: ignore[reportAttributeAccessIssue]iftypevar.__constraints__:returnself._union_schema(typing.Union[typevar.__constraints__])iftypevar.__bound__:schema=self.generate_schema(typevar.__bound__)schema['serialization']=core_schema.wrap_serializer_function_ser_schema(lambdax,h:h(x),schema=core_schema.any_schema(),            )returnschemareturncore_schema.any_schema()

Totally agree that it's safe.
I started this PR as supporting equals bound/default, but recognized that it's unnecessary limitation.

This code only works for unsubstituted models, so we simply prioritize the default type (expected behavior for me).
Python Type checker will check ifdefault is not a subtype ofbound inTypeVar.

I will take Viicos suggestion

Python will check and won't start ifdefault is not a subtype ofbound inTypeVar.

It doesn't, only static type checkers enforce it :)