fix: Fix missing fields from auto generated connections (#137)

We changed auto generated edges/connections to inherit from
`relay.Edge`/`relay.Connection`, which requires some extra fields to be
instantiated.

Fix #97

Author: bellini666

RELEASE.md

@@ -0,0 +1,4 @@
+Release type: patch
+
+Fix an issue where auto generated connections were missing some expected
+attributes to be properly instantiated.

src/strawberry_sqlalchemy_mapper/mapper.py

@@ -463,13 +463,22 @@ def make_connection_wrapper_resolver(
         edge_type = self._edge_type_for(type_name)
 
         async def wrapper(self, info: Info):
+            # TODO: Add pagination support to dataloader resolvers
+            edges = [
+                edge_type.resolve_edge(
+                    related_object,
+                    cursor=i,
+                )
+                for i, related_object in enumerate(await resolver(self, info))
+            ]
             return connection_type(
-                edges=[
-                    edge_type(
-                        node=related_object,
-                    )
-                    for related_object in await resolver(self, info)
-                ]
+                edges=edges,
+                page_info=relay.PageInfo(
+                    has_next_page=False,
+                    has_previous_page=False,
+                    start_cursor=edges[0].cursor if edges else None,
+                    end_cursor=edges[-1].cursor if edges else None,
+                ),
             )
 
         setattr(wrapper, _IS_GENERATED_RESOLVER_KEY, True)
@@ -732,7 +741,9 @@ def convert(type_: Any) -> Any:
                         StrawberryField,
                         field(
                             resolver=self.association_proxy_resolver_for(
-                                mapper, descriptor, strawberry_type  # type: ignore[arg-type]
+                                mapper,
+                                descriptor,
+                                strawberry_type,  # type: ignore[arg-type]
                             )
                         ),
                     )

tests/relay/test_auto_connections.py

@@ -0,0 +1,125 @@
+from typing import Any
+
+import pytest
+import strawberry
+from sqlalchemy import Column, ForeignKey, Integer, String
+from sqlalchemy.ext.asyncio.engine import AsyncEngine
+from sqlalchemy.orm import relationship
+from strawberry.relay.utils import to_base64
+from strawberry_sqlalchemy_mapper import StrawberrySQLAlchemyMapper
+from strawberry_sqlalchemy_mapper.loader import StrawberrySQLAlchemyLoader
+
+
+@pytest.fixture
+def user_and_group_tables(base: Any):
+    class User(base):
+        __tablename__ = "user"
+        id = Column(Integer, autoincrement=True, primary_key=True)
+        name = Column(String(50), nullable=False)
+        group_id = Column(Integer, ForeignKey("group.id"))
+        group = relationship("Group", back_populates="users")
+
+    class Group(base):
+        __tablename__ = "group"
+        id = Column(Integer, autoincrement=True, primary_key=True)
+        name = Column(String, nullable=False)
+        users = relationship("User", back_populates="group")
+
+    return User, Group
+
+
+@pytest.mark.asyncio
+async def test_query_auto_generated_connection(
+    base: Any,
+    async_engine: AsyncEngine,
+    async_sessionmaker,
+    user_and_group_tables,
+):
+    user_table, group_table = user_and_group_tables
+
+    async with async_engine.begin() as conn:
+        await conn.run_sync(base.metadata.create_all)
+    mapper = StrawberrySQLAlchemyMapper()
+
+    global User, Group
+    try:
+
+        @mapper.type(user_table)
+        class User:
+            ...
+
+        @mapper.type(group_table)
+        class Group:
+            ...
+
+        @strawberry.type
+        class Query:
+            @strawberry.field
+            async def group(self, id: strawberry.ID) -> Group:
+                session = async_sessionmaker()
+                return await session.get(group_table, int(id))
+
+        schema = strawberry.Schema(query=Query)
+
+        query = """\
+        query GetGroup ($id: ID!) {
+          group(id: $id) {
+            id
+            name
+            users {
+              pageInfo {
+                hasNextPage
+                hasPreviousPage
+                startCursor
+                endCursor
+              }
+              edges {
+                node {
+                  id
+                  name
+                }
+              }
+            }
+          }
+        }
+        """
+
+        async with async_sessionmaker(expire_on_commit=False) as session:
+            group = group_table(name="Foo Bar")
+            user1 = user_table(name="User 1", group=group)
+            user2 = user_table(name="User 2", group=group)
+            user3 = user_table(name="User 3", group=group)
+            session.add_all([group, user1, user2, user3])
+            await session.commit()
+
+            result = await schema.execute(
+                query,
+                variable_values={"id": group.id},
+                context_value={
+                    "sqlalchemy_loader": StrawberrySQLAlchemyLoader(
+                        async_bind_factory=async_sessionmaker
+                    )
+                },
+            )
+            assert result.errors is None
+            assert result.data == {
+                "group": {
+                    "id": group.id,
+                    "name": "Foo Bar",
+                    "users": {
+                        "pageInfo": {
+                            "hasNextPage": False,
+                            "hasPreviousPage": False,
+                            "startCursor": to_base64("arrayconnection", "0"),
+                            "endCursor": to_base64("arrayconnection", "2"),
+                        },
+                        "edges": [
+                            {"node": {"id": user1.id, "name": "User 1"}},
+                            {"node": {"id": user2.id, "name": "User 2"}},
+                            {"node": {"id": user3.id, "name": "User 3"}},
+                        ],
+                    },
+                },
+            }
+    finally:
+        del User, Group