fix: widen JoinType to accept aliased and polymorphic targets (#221)

src/fastapi_toolsets/types.py

@@ -15,7 +15,7 @@ ModelType = TypeVar("ModelType", bound=DeclarativeBase)
 SchemaType = TypeVar("SchemaType", bound=BaseModel)
 
 # CRUD type aliases
-JoinType = list[tuple[type[DeclarativeBase], Any]]
+JoinType = list[tuple[type[DeclarativeBase] | Any, Any]]
 M2MFieldType = Mapping[str, QueryableAttribute[Any]]
 OrderByClause = ColumnElement[Any] | QueryableAttribute[Any]
 

tests/conftest.py

@@ -139,6 +139,17 @@ class Post(Base):
     tags: Mapped[list[Tag]] = relationship(secondary=post_tags)
 
 
+class Transfer(Base):
+    """Test model with two FKs to the same table (users)."""
+
+    __tablename__ = "transfers"
+
+    id: Mapped[uuid.UUID] = mapped_column(Uuid, primary_key=True, default=uuid.uuid4)
+    amount: Mapped[str] = mapped_column(String(50))
+    sender_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"))
+    receiver_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"))
+
+
 class Article(Base):
     """Test article model with ARRAY and JSON columns."""
 
@@ -300,6 +311,23 @@ class ArticleRead(PydanticBase):
     labels: list[str]
 
 
+class TransferCreate(BaseModel):
+    """Schema for creating a transfer."""
+
+    id: uuid.UUID | None = None
+    amount: str
+    sender_id: uuid.UUID
+    receiver_id: uuid.UUID
+
+
+class TransferRead(PydanticBase):
+    """Schema for reading a transfer."""
+
+    id: uuid.UUID
+    amount: str
+
+
+TransferCrud = CrudFactory(Transfer)
 ArticleCrud = CrudFactory(Article)
 RoleCrud = CrudFactory(Role)
 RoleCursorCrud = CrudFactory(Role, cursor_column=Role.id)

tests/test_crud.py

@@ -38,6 +38,10 @@ from .conftest import (
     Tag,
     TagCreate,
     TagCrud,
+    Transfer,
+    TransferCreate,
+    TransferCrud,
+    TransferRead,
     User,
     UserCreate,
     UserCrud,
@@ -1282,6 +1286,128 @@ class TestCrudJoins:
         assert users[0].username == "multi_join"
 
 
+class TestCrudAliasedJoins:
+    """Tests for CRUD operations with aliased joins (same table joined twice)."""
+
+    @pytest.mark.anyio
+    async def test_get_multi_with_aliased_joins(self, db_session: AsyncSession):
+        """Aliased joins allow joining the same table twice."""
+        from sqlalchemy.orm import aliased
+
+        alice = await UserCrud.create(
+            db_session, UserCreate(username="alice", email="alice@test.com")
+        )
+        bob = await UserCrud.create(
+            db_session, UserCreate(username="bob", email="bob@test.com")
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="100", sender_id=alice.id, receiver_id=bob.id),
+        )
+
+        Sender = aliased(User)
+        Receiver = aliased(User)
+
+        results = await TransferCrud.get_multi(
+            db_session,
+            joins=[
+                (Sender, Transfer.sender_id == Sender.id),
+                (Receiver, Transfer.receiver_id == Receiver.id),
+            ],
+            filters=[Sender.username == "alice", Receiver.username == "bob"],
+        )
+        assert len(results) == 1
+        assert results[0].amount == "100"
+
+    @pytest.mark.anyio
+    async def test_get_multi_aliased_no_match(self, db_session: AsyncSession):
+        """Aliased joins correctly filter out non-matching rows."""
+        from sqlalchemy.orm import aliased
+
+        alice = await UserCrud.create(
+            db_session, UserCreate(username="alice", email="alice@test.com")
+        )
+        bob = await UserCrud.create(
+            db_session, UserCreate(username="bob", email="bob@test.com")
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="100", sender_id=alice.id, receiver_id=bob.id),
+        )
+
+        Sender = aliased(User)
+        Receiver = aliased(User)
+
+        # bob is receiver, not sender — should return nothing
+        results = await TransferCrud.get_multi(
+            db_session,
+            joins=[
+                (Sender, Transfer.sender_id == Sender.id),
+                (Receiver, Transfer.receiver_id == Receiver.id),
+            ],
+            filters=[Sender.username == "bob", Receiver.username == "alice"],
+        )
+        assert len(results) == 0
+
+    @pytest.mark.anyio
+    async def test_paginate_with_aliased_joins(self, db_session: AsyncSession):
+        """Aliased joins work with offset_paginate."""
+        from sqlalchemy.orm import aliased
+
+        alice = await UserCrud.create(
+            db_session, UserCreate(username="alice", email="alice@test.com")
+        )
+        bob = await UserCrud.create(
+            db_session, UserCreate(username="bob", email="bob@test.com")
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="50", sender_id=alice.id, receiver_id=bob.id),
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="75", sender_id=bob.id, receiver_id=alice.id),
+        )
+
+        Sender = aliased(User)
+        result = await TransferCrud.offset_paginate(
+            db_session,
+            joins=[(Sender, Transfer.sender_id == Sender.id)],
+            filters=[Sender.username == "alice"],
+            schema=TransferRead,
+        )
+        assert result.pagination.total_count == 1
+        assert result.data[0].amount == "50"
+
+    @pytest.mark.anyio
+    async def test_count_with_aliased_join(self, db_session: AsyncSession):
+        """Aliased joins work with count."""
+        from sqlalchemy.orm import aliased
+
+        alice = await UserCrud.create(
+            db_session, UserCreate(username="alice", email="alice@test.com")
+        )
+        bob = await UserCrud.create(
+            db_session, UserCreate(username="bob", email="bob@test.com")
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="10", sender_id=alice.id, receiver_id=bob.id),
+        )
+        await TransferCrud.create(
+            db_session,
+            TransferCreate(amount="20", sender_id=alice.id, receiver_id=bob.id),
+        )
+
+        Sender = aliased(User)
+        count = await TransferCrud.count(
+            db_session,
+            joins=[(Sender, Transfer.sender_id == Sender.id)],
+            filters=[Sender.username == "alice"],
+        )
+        assert count == 2
+
+
 class TestCrudFactoryM2M:
     """Tests for CrudFactory with m2m_fields parameter."""