Change Summary

Fixes#10279, partiallyfixes#9887.

We avoid caching parametrized models when in the process of parametrizing another model, as the result ofBaseModel.__class_getitem__ can returnPydanticRecursiveRef instances in this case. In the model core schema generation logic, we mutateFieldInfo instances if the annotation wasn't evaluated yet, meaning we could set the annotation to some typing construct containing aPydanticRecursiveRef, e.g. with:

classModel1[T](BaseModel):# When evaluated, this annotation will be a `PydanticRecursiveRef`model2:'Model2[T]'classModel2[S](BaseModel):model1:Model1[S]

Because theseFieldInfo instances come from themodel_fields attribute of the model class, having the caching logic here can result in a parametrized model class with aFieldInfo containingPydanticRecursiveRef instances when we later parametrize a model (e.g.Model1[str]).

Note that is hopefully not a long term solution, as this doesn't fix what is an even simpler repro:#9969.

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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
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