Add is_type_of to PydanticObjectType to support Graphene Union

Author: arun-sureshkumar

graphene_pydantic/objecttype.py

@@ -4,6 +4,7 @@
 import pydantic
 from graphene.types.objecttype import ObjectTypeOptions
 from graphene.types.utils import yank_fields_from_attrs
+from graphql import GraphQLResolveInfo
 
 from .converters import convert_pydantic_field
 from .registry import Placeholder, Registry, get_global_registry
@@ -18,11 +19,11 @@ class PydanticObjectTypeOptions(ObjectTypeOptions):
 
 
 def construct_fields(
-    obj_type: T.Type["PydanticObjectType"],
-    model: T.Type[pydantic.BaseModel],
-    registry: Registry,
-    only_fields: T.Tuple[str, ...],
-    exclude_fields: T.Tuple[str, ...],
+        obj_type: T.Type["PydanticObjectType"],
+        model: T.Type[pydantic.BaseModel],
+        registry: Registry,
+        only_fields: T.Tuple[str, ...],
+        exclude_fields: T.Tuple[str, ...],
 ) -> T.Dict[str, graphene.Field]:
     """
     Construct all the fields for a PydanticObjectType.
@@ -59,16 +60,16 @@ class PydanticObjectType(graphene.ObjectType):
 
     @classmethod
     def __init_subclass_with_meta__(
-        cls,
-        model: type = None,
-        registry: Registry = None,
-        skip_registry: bool = False,
-        only_fields: T.Tuple[str, ...] = (),
-        exclude_fields: T.Tuple[str, ...] = (),
-        interfaces=(),
-        id=None,
-        _meta=None,
-        **options,
+            cls,
+            model: type = None,
+            registry: Registry = None,
+            skip_registry: bool = False,
+            only_fields: T.Tuple[str, ...] = (),
+            exclude_fields: T.Tuple[str, ...] = (),
+            interfaces=(),
+            id=None,
+            _meta=None,
+            **options,
     ):
         assert model and issubclass(
             model, pydantic.BaseModel
@@ -154,3 +155,7 @@ def resolve_placeholders(cls):
                 meta.registry.register_object_field(cls, name, pydantic_field)
         # update the graphene side of things
         meta.fields.update(fields_to_update)
+
+    @classmethod
+    def is_type_of(cls, root, _: GraphQLResolveInfo) -> bool:
+        return root.__annotations__ == cls._meta.model.__annotations__