Fix pydantic type decorator - add missing internal methods

RELEASE.md

@@ -0,0 +1,3 @@
+Release type: patch
+
+Fix pydantic type decorator - add internal methods not copied by `dataclasses.make_dataclass()`

strawberry/experimental/pydantic/object_type.py

@@ -237,14 +237,21 @@ def is_type_of(cls: Type, obj: Any, _info: GraphQLResolveInfo) -> bool:
         else:
             kwargs["init"] = False
 
-        cls = dataclasses.make_dataclass(
+        new_cls = dataclasses.make_dataclass(
             cls.__name__,
             [field.to_tuple() for field in all_model_fields],
             bases=cls.__bases__,
             namespace=namespace,
             **kwargs,  # type: ignore
         )
 
+        # Add back attributes that were not copied (like internal methods)
+        for key, value in vars(cls).items():
+            if not hasattr(new_cls, key):
+                setattr(new_cls, key, value)
+
+        cls = new_cls
+
         if sys.version_info < (3, 10, 1):
             add_custom_init_fn(cls)
 

tests/experimental/pydantic/test_basic.py

@@ -141,6 +141,30 @@ class UserType:
     assert field3.type is other_sentinel
 
 
+def test_basic_type_with_internal_method():
+    class User(pydantic.BaseModel):
+        age: int
+        password: Optional[str]
+
+    @strawberry.experimental.pydantic.type(User)
+    class UserType:
+        age: strawberry.auto
+        password: strawberry.auto
+
+        @strawberry.field
+        def password_hash(self) -> int:
+            return self.perform_hash(self.password)
+
+        def perform_hash(self, data: str) -> int:
+            return hash(data)
+
+    definition: StrawberryObjectDefinition = UserType.__strawberry_definition__
+    assert definition.name == "UserType"
+
+    assert len(definition.fields) == 3
+    assert hasattr(UserType, "perform_hash")
+
+
 def test_referencing_other_models_fails_when_not_registered():
     class Group(pydantic.BaseModel):
         name: str