fix: improve handling of awaitables in default_type_resolver

Replicates graphql/graphql-js@98b6541

Author: Cito

src/graphql/execution/execute.py

@@ -2428,6 +2428,16 @@ def default_type_resolver(
                 append_awaitable_result(cast("Awaitable[bool]", is_type_of_result))
                 append_awaitable_type(type_)
             elif is_type_of_result:
+                if awaitable_is_type_of_results:
+
+                    async def await_is_type_of_and_return_type(
+                        resolved_type_name: str = type_.name,
+                    ) -> str:
+                        with suppress(Exception):
+                            await gather_with_cancel(*awaitable_is_type_of_results)
+                        return resolved_type_name
+
+                    return await_is_type_of_and_return_type()
                 return type_.name
 
     if awaitable_is_type_of_results:

tests/execution/test_union_interface.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 
-from graphql.execution import execute_sync
+import pytest
+
+from graphql.execution import ExecutionResult, execute, execute_sync
 from graphql.language import parse
 from graphql.type import (
     GraphQLBoolean,
@@ -13,6 +15,8 @@
     GraphQLUnionType,
 )
 
+pytestmark = pytest.mark.anyio
+
 
 class Dog:
     name: str
@@ -44,20 +48,30 @@ def __init__(self, name: str, meows: bool):
         self.progeny = []
 
 
+class Plant:
+    name: str
+
+    def __init__(self, name: str):
+        self.name = name
+
+
 class Person:
     name: str
     pets: list[Dog | Cat] | None
     friends: list[Dog | Cat | Person] | None
+    responsibilities: list[Dog | Cat | Plant] | None
 
     def __init__(
         self,
         name: str,
         pets: list[Dog | Cat] | None = None,
         friends: list[Dog | Cat | Person] | None = None,
+        responsibilities: list[Dog | Cat | Plant] | None = None,
     ):
         self.name = name
         self.pets = pets
         self.friends = friends
+        self.responsibilities = responsibilities
 
 
 NamedType = GraphQLInterfaceType("Named", {"name": GraphQLField(GraphQLString)})
@@ -104,24 +118,39 @@ def __init__(
 )
 
 
+async def resolve_plant_type(_value, _info) -> bool:
+    raise RuntimeError("Not sure if this is a plant")
+
+
+PlantType = GraphQLObjectType(
+    "Plant",
+    lambda: {"name": GraphQLField(GraphQLString)},
+    interfaces=[NamedType],
+    is_type_of=resolve_plant_type,
+)
+
+
 def resolve_pet_type(value, _info, _type):
     if isinstance(value, Dog):
         return DogType.name
     if isinstance(value, Cat):
         return CatType.name
 
     # Not reachable. All possible types have been considered.
-    assert False, "Unexpected pet type"  # pragma: no cover
+    pytest.fail("Unexpected pet type")  # pragma: no cover
 
 
 PetType = GraphQLUnionType("Pet", [DogType, CatType], resolve_type=resolve_pet_type)
 
+PetOrPlantType = GraphQLUnionType("PetOrPlantType", [PlantType, DogType, CatType])
+
 PersonType = GraphQLObjectType(
     "Person",
     lambda: {
         "name": GraphQLField(GraphQLString),
         "pets": GraphQLField(GraphQLList(PetType)),
         "friends": GraphQLField(GraphQLList(NamedType)),
+        "responsibilities": GraphQLField(GraphQLList(PetOrPlantType)),
         "progeny": GraphQLField(GraphQLList(PersonType)),  # type: ignore
         "mother": GraphQLField(PersonType),  # type: ignore
         "father": GraphQLField(PersonType),  # type: ignore
@@ -140,8 +169,9 @@ def resolve_pet_type(value, _info, _type):
 odie.mother = Dog("Odie's Mom", True)
 odie.mother.progeny = [odie]
 
+fern = Plant("Fern")
 liz = Person("Liz", [], [])
-john = Person("John", [garfield, odie], [liz, odie])
+john = Person("John", [garfield, odie], [liz, odie], [garfield, fern])
 
 
 def describe_execute_union_and_intersection_types():
@@ -191,6 +221,7 @@ def can_introspect_on_union_and_intersection_types():
                         {"name": "Dog"},
                         {"name": "Cat"},
                         {"name": "Person"},
+                        {"name": "Plant"},
                     ],
                     "enumValues": None,
                     "inputFields": None,
@@ -525,3 +556,38 @@ def resolve_type(_source, info, _type):
             "root_value": root_value,
             "context": context_value,
         }
+
+    @pytest.mark.filterwarnings("error:.*was never awaited:RuntimeWarning")
+    async def handles_rejections_from_is_type_of_after_an_is_type_of_returns_true():
+        document = parse("""
+            {
+                responsibilities {
+                __typename
+                ... on Dog {
+                    name
+                    barks
+                }
+                ... on Cat {
+                    name
+                    meows
+                }
+                }
+            }
+            """)
+
+        root_value = Person("John", [], [liz], [garfield])
+        context_value = {"authToken": "123abc"}
+
+        result = execute(schema, document, root_value, context_value)
+        assert not isinstance(result, ExecutionResult)
+        result = await result
+        assert isinstance(result, ExecutionResult)
+
+        assert result == (
+            {
+                "responsibilities": [
+                    {"__typename": "Cat", "name": "Garfield", "meows": False},
+                ],
+            },
+            None,
+        )