Fix issue with unnamed unions and generics (#3099)

* Fix issue with unnamed unions and generics

* Remove unused resolvers

* Ignore 3.12 in black for now

.pre-commit-config.yaml

@@ -3,7 +3,7 @@ repos:
     rev: 23.7.0
     hooks:
       - id: black
-        exclude: ^tests/\w+/snapshots/
+        exclude: ^(tests/\w+/snapshots/|tests/python_312/)
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: v0.0.280

RELEASE.md

@@ -0,0 +1,31 @@
+Release type: patch
+
+This release fixes an issue that would prevent using generics with unnamed
+unions, like in this example:
+
+```python
+from typing import Generic, TypeVar, Union
+import strawberry
+
+T = TypeVar("T")
+
+
+@strawberry.type
+class Connection(Generic[T]):
+    nodes: list[T]
+
+
+@strawberry.type
+class Entity1:
+    id: int
+
+
+@strawberry.type
+class Entity2:
+    id: int
+
+
+@strawberry.type
+class Query:
+    entities: Connection[Union[Entity1, Entity2]]
+```

strawberry/schema/name_converter.py

@@ -146,10 +146,7 @@ def get_from_type(self, type_: Union[StrawberryType, type]) -> str:
         elif isinstance(type_, EnumDefinition):
             name = type_.name
         elif isinstance(type_, StrawberryUnion):
-            # TODO: test Generics with unnamed unions
-            assert type_.graphql_name
-
-            name = type_.graphql_name
+            name = type_.graphql_name if type_.graphql_name else self.from_union(type_)
         elif isinstance(type_, StrawberryList):
             name = self.get_from_type(type_.of_type) + "List"
         elif isinstance(type_, StrawberryOptional):

tests/python_312/test_generics.py

@@ -1172,3 +1172,58 @@ def real(self) -> Abstract:
 
     assert not query_result.errors
     assert query_result.data == {"real": {"__typename": "IntReal", "x": ""}}
+
+
+
+def test_generics_via_anonymous_union():
+    @strawberry.type
+    class Edge[T]:
+        cursor: str
+        node: T
+
+    @strawberry.type
+    class Connection[T]:
+        edges: list[Edge[T]]
+
+    @strawberry.type
+    class Entity1:
+        id: int
+
+    @strawberry.type
+    class Entity2:
+        id: int
+
+    @strawberry.type
+    class Query:
+        entities: Connection[Union[Entity1, Entity2]]
+
+    schema = strawberry.Schema(query=Query)
+
+    expected_schema = textwrap.dedent(
+        """
+        type Entity1 {
+          id: Int!
+        }
+
+        union Entity1Entity2 = Entity1 | Entity2
+
+        type Entity1Entity2Connection {
+          edges: [Entity1Entity2Edge!]!
+        }
+
+        type Entity1Entity2Edge {
+          cursor: String!
+          node: Entity1Entity2!
+        }
+
+        type Entity2 {
+          id: Int!
+        }
+
+        type Query {
+          entities: Entity1Entity2Connection!
+        }
+        """
+    ).strip()
+
+    assert str(schema) == expected_schema

tests/schema/test_generics.py

@@ -768,6 +768,62 @@ def example(self) -> List[Union[Edge[int], Edge[str]]]:
     }
 
 
+def test_generics_via_anonymous_union():
+    T = TypeVar("T")
+
+    @strawberry.type
+    class Edge(Generic[T]):
+        cursor: str
+        node: T
+
+    @strawberry.type
+    class Connection(Generic[T]):
+        edges: list[Edge[T]]
+
+    @strawberry.type
+    class Entity1:
+        id: int
+
+    @strawberry.type
+    class Entity2:
+        id: int
+
+    @strawberry.type
+    class Query:
+        entities: Connection[Union[Entity1, Entity2]]
+
+    schema = strawberry.Schema(query=Query)
+
+    expected_schema = textwrap.dedent(
+        """
+        type Entity1 {
+          id: Int!
+        }
+
+        union Entity1Entity2 = Entity1 | Entity2
+
+        type Entity1Entity2Connection {
+          edges: [Entity1Entity2Edge!]!
+        }
+
+        type Entity1Entity2Edge {
+          cursor: String!
+          node: Entity1Entity2!
+        }
+
+        type Entity2 {
+          id: Int!
+        }
+
+        type Query {
+          entities: Entity1Entity2Connection!
+        }
+        """
+    ).strip()
+
+    assert str(schema) == expected_schema
+
+
 def test_generated_names():
     T = TypeVar("T")