Handle all schema generation errors in InstanceOf (pydantic#12705)

Author: Viicos

pydantic/_internal/_generate_schema.py

@@ -58,7 +58,13 @@
 from ..aliases import AliasChoices, AliasPath
 from ..annotated_handlers import GetCoreSchemaHandler, GetJsonSchemaHandler
 from ..config import ConfigDict, JsonDict, JsonEncoder, JsonSchemaExtraCallable
-from ..errors import PydanticSchemaGenerationError, PydanticUndefinedAnnotation, PydanticUserError
+from ..errors import (
+    PydanticForbiddenQualifier,
+    PydanticInvalidForJsonSchema,
+    PydanticSchemaGenerationError,
+    PydanticUndefinedAnnotation,
+    PydanticUserError,
+)
 from ..functional_validators import AfterValidator, BeforeValidator, FieldValidatorModes, PlainValidator, WrapValidator
 from ..json_schema import JsonSchemaValue
 from ..version import version_short
@@ -328,6 +334,15 @@ def _add_custom_serialization_from_json_encoders(
     return schema
 
 
+GENERATE_SCHEMA_ERRORS = (
+    PydanticForbiddenQualifier,
+    PydanticInvalidForJsonSchema,
+    PydanticSchemaGenerationError,
+    PydanticUndefinedAnnotation,
+)
+"""Errors raised during core schema generation. This does *not* include `InvalidSchemaError`, which is raised during schema cleaning."""
+
+
 class InvalidSchemaError(Exception):
     """The core schema is invalid."""
 

pydantic/functional_validators.py

@@ -782,15 +782,15 @@ def __class_getitem__(cls, item: AnyType) -> AnyType:
 
         @classmethod
         def __get_pydantic_core_schema__(cls, source: Any, handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
-            from pydantic import PydanticSchemaGenerationError
+            from pydantic._internal._generate_schema import GENERATE_SCHEMA_ERRORS
 
             # use the generic _origin_ as the second argument to isinstance when appropriate
             instance_of_schema = core_schema.is_instance_schema(_generics.get_origin(source) or source)
 
             try:
                 # Try to generate the "standard" schema, which will be used when loading from JSON
                 original_schema = handler(source)
-            except PydanticSchemaGenerationError:
+            except GENERATE_SCHEMA_ERRORS:
                 # If that fails, just produce a schema that can validate from python
                 return instance_of_schema
             else:

tests/test_types.py

@@ -6268,14 +6268,22 @@ def test_instanceof_invalid_core_schema():
     class MyClass:
         pass
 
+    @dataclass
+    class ClassWithInvalidAnnotations:
+        a: 'Unknown' = 1  # noqa: F821
+        b: NotRequired[int] = 1
+
     class MyModel(BaseModel):
         a: InstanceOf[MyClass]
         b: Optional[InstanceOf[MyClass]]
+        c: InstanceOf[ClassWithInvalidAnnotations]
+
+    MyModel(a=MyClass(), b=None, c=ClassWithInvalidAnnotations())
+    MyModel(a=MyClass(), b=MyClass(), c=ClassWithInvalidAnnotations())
 
-    MyModel(a=MyClass(), b=None)
-    MyModel(a=MyClass(), b=MyClass())
     with pytest.raises(ValidationError) as exc_info:
-        MyModel(a=1, b=1)
+        MyModel(a=1, b=1, c=1)
+
     assert exc_info.value.errors(include_url=False) == [
         {
             'ctx': {'class': 'test_instanceof_invalid_core_schema.<locals>.MyClass'},
@@ -6291,6 +6299,13 @@ class MyModel(BaseModel):
             'msg': 'Input should be an instance of test_instanceof_invalid_core_schema.<locals>.MyClass',
             'type': 'is_instance_of',
         },
+        {
+            'ctx': {'class': 'test_instanceof_invalid_core_schema.<locals>.ClassWithInvalidAnnotations'},
+            'input': 1,
+            'loc': ('c',),
+            'msg': 'Input should be an instance of test_instanceof_invalid_core_schema.<locals>.ClassWithInvalidAnnotations',
+            'type': 'is_instance_of',
+        },
     ]
     with pytest.raises(
         PydanticInvalidForJsonSchema, match='Cannot generate a JsonSchema for core_schema.IsInstanceSchema'