Refactor database session management across multiple API endpoints to utilize a transactional session, enhancing consistency in transaction handling. Update dependencies in costs, financials, groups, health, invites, items, and lists modules for improved error handling and reliability.

be/app/api/v1/endpoints/costs.py

@@ -7,7 +7,7 @@ from sqlalchemy.orm import Session, selectinload
 from decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN
 from typing import List
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 from app.models import (
     User as UserModel,
@@ -120,7 +120,7 @@ def calculate_suggested_settlements(user_balances: List[UserBalanceDetail]) -> L
 )
 async def get_list_cost_summary(
     list_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -282,7 +282,7 @@ async def get_list_cost_summary(
 )
 async def get_group_balance_summary(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """

be/app/api/v1/endpoints/financials.py

@@ -5,7 +5,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
 from typing import List as PyList, Optional, Sequence
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 from app.models import User as UserModel, Group as GroupModel, List as ListModel, UserGroup as UserGroupModel, UserRoleEnum
 from app.schemas.expense import (
@@ -46,7 +46,7 @@ async def check_list_access_for_financials(db: AsyncSession, list_id: int, user_
 )
 async def create_new_expense(
     expense_in: ExpenseCreate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} creating expense: {expense_in.description}")
@@ -109,7 +109,7 @@ async def create_new_expense(
 @router.get("/expenses/{expense_id}", response_model=ExpensePublic, summary="Get Expense by ID", tags=["Expenses"])
 async def get_expense(
     expense_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} requesting expense ID {expense_id}")
@@ -130,7 +130,7 @@ async def list_list_expenses(
     list_id: int,
     skip: int = Query(0, ge=0),
     limit: int = Query(100, ge=1, le=200),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} listing expenses for list ID {list_id}")
@@ -143,7 +143,7 @@ async def list_group_expenses(
     group_id: int,
     skip: int = Query(0, ge=0),
     limit: int = Query(100, ge=1, le=200),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} listing expenses for group ID {group_id}")
@@ -155,7 +155,7 @@ async def list_group_expenses(
 async def update_expense_details(
     expense_id: int,
     expense_in: ExpenseUpdate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -209,7 +209,7 @@ async def update_expense_details(
 async def delete_expense_record(
     expense_id: int,
     expected_version: Optional[int] = Query(None, description="Expected version for optimistic locking"),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -273,7 +273,7 @@ async def delete_expense_record(
 )
 async def create_new_settlement(
     settlement_in: SettlementCreate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} recording settlement in group {settlement_in.group_id}")
@@ -299,7 +299,7 @@ async def create_new_settlement(
 @router.get("/settlements/{settlement_id}", response_model=SettlementPublic, summary="Get Settlement by ID", tags=["Settlements"])
 async def get_settlement(
     settlement_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} requesting settlement ID {settlement_id}")
@@ -321,7 +321,7 @@ async def list_group_settlements(
     group_id: int,
     skip: int = Query(0, ge=0),
     limit: int = Query(100, ge=1, le=200),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     logger.info(f"User {current_user.email} listing settlements for group ID {group_id}")
@@ -333,7 +333,7 @@ async def list_group_settlements(
 async def update_settlement_details(
     settlement_id: int,
     settlement_in: SettlementUpdate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -387,7 +387,7 @@ async def update_settlement_details(
 async def delete_settlement_record(
     settlement_id: int,
     expected_version: Optional[int] = Query(None, description="Expected version for optimistic locking"),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """

be/app/api/v1/endpoints/groups.py

@@ -5,13 +5,13 @@ from typing import List
 from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 from app.models import User as UserModel, UserRoleEnum # Import model and enum
 from app.schemas.group import GroupCreate, GroupPublic
 from app.schemas.invite import InviteCodePublic
 from app.schemas.message import Message # For simple responses
-from app.schemas.list import ListPublic
+from app.schemas.list import ListPublic, ListDetail
 from app.crud import group as crud_group
 from app.crud import invite as crud_invite
 from app.crud import list as crud_list
@@ -36,7 +36,7 @@ router = APIRouter()
 )
 async def create_group(
     group_in: GroupCreate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Creates a new group, adding the creator as the owner."""
@@ -54,7 +54,7 @@ async def create_group(
     tags=["Groups"]
 )
 async def read_user_groups(
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Retrieves all groups the current user is a member of."""
@@ -71,7 +71,7 @@ async def read_user_groups(
 )
 async def read_group(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Retrieves details for a specific group, including members, if the user is part of it."""
@@ -98,7 +98,7 @@ async def read_group(
 )
 async def create_group_invite(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Generates a new invite code for the group. Requires owner/admin role (MVP: owner only)."""
@@ -121,15 +121,7 @@ async def create_group_invite(
         # This case should ideally be covered by exceptions from create_invite now
         raise InviteCreationError(group_id)
 
-    try:
+    logger.info(f"User {current_user.email} created invite code for group {group_id}")
-        await db.commit() # Explicit commit before returning
-        logger.info(f"User {current_user.email} created and committed invite code for group {group_id}")
-    except Exception as e:
-        logger.error(f"Failed to commit transaction after creating invite for group {group_id}: {e}", exc_info=True)
-        await db.rollback() # Ensure rollback if explicit commit fails
-        # Re-raise to ensure a 500 error is returned
-        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=f"Failed to save invite: {str(e)}")
-
     return invite
 
 @router.get(
@@ -140,7 +132,7 @@ async def create_group_invite(
 )
 async def get_group_active_invite(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Retrieves the active invite code for the group. Requires group membership (owner/admin to be stricter later if needed)."""
@@ -177,7 +169,7 @@ async def get_group_active_invite(
 )
 async def leave_group(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Removes the current user from the specified group."""
@@ -216,7 +208,7 @@ async def leave_group(
 async def remove_group_member(
     group_id: int,
     user_id_to_remove: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Removes a specified user from the group. Requires current user to be owner."""
@@ -249,13 +241,13 @@ async def remove_group_member(
 
 @router.get(
     "/{group_id}/lists",
-    response_model=List[ListPublic],
+    response_model=List[ListDetail],
     summary="Get Group Lists",
     tags=["Groups", "Lists"]
 )
 async def read_group_lists(
     group_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Retrieves all lists belonging to a specific group, if the user is a member."""

be/app/api/v1/endpoints/health.py

@@ -4,7 +4,7 @@ from fastapi import APIRouter, Depends
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.sql import text
 
-from app.database import get_async_session
+from app.database import get_transactional_session
 from app.schemas.health import HealthStatus
 from app.core.exceptions import DatabaseConnectionError
 
@@ -18,7 +18,7 @@ router = APIRouter()
     description="Checks the operational status of the API and its connection to the database.",
     tags=["Health"]
 )
-async def check_health(db: AsyncSession = Depends(get_async_session)):
+async def check_health(db: AsyncSession = Depends(get_transactional_session)):
     """
     Health check endpoint. Verifies API reachability and database connection.
     """

be/app/api/v1/endpoints/invites.py

@@ -3,7 +3,7 @@ import logging
 from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 from app.models import User as UserModel, UserRoleEnum
 from app.schemas.invite import InviteAccept
@@ -30,7 +30,7 @@ router = APIRouter()
 )
 async def accept_invite(
     invite_in: InviteAccept,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Accepts a group invite using the provided invite code."""

be/app/api/v1/endpoints/items.py

@@ -5,7 +5,7 @@ from typing import List as PyList, Optional
 from fastapi import APIRouter, Depends, HTTPException, status, Response, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 # --- Import Models Correctly ---
 from app.models import User as UserModel
@@ -23,7 +23,7 @@ router = APIRouter()
 # Now ItemModel is defined before being used as a type hint
 async def get_item_and_verify_access(
     item_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user)
 ) -> ItemModel:
     """Dependency to get an item and verify the user has access to its list."""
@@ -52,7 +52,7 @@ async def get_item_and_verify_access(
 async def create_list_item(
     list_id: int,
     item_in: ItemCreate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """Adds a new item to a specific list. User must have access to the list."""
@@ -80,7 +80,7 @@ async def create_list_item(
 )
 async def read_list_items(
     list_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
     # Add sorting/filtering params later if needed: sort_by: str = 'created_at', order: str = 'asc'
 ):
@@ -99,7 +99,7 @@ async def read_list_items(
 
 
 @router.put(
-    "/items/{item_id}", # Operate directly on item ID
+    "/lists/{list_id}/items/{item_id}", # Nested under lists
     response_model=ItemPublic,
     summary="Update Item",
     tags=["Items"],
@@ -108,10 +108,11 @@ async def read_list_items(
     }
 )
 async def update_item(
-    item_id: int, # Item ID from path
+    list_id: int,
+    item_id: int,
     item_in: ItemUpdate,
     item_db: ItemModel = Depends(get_item_and_verify_access), # Use dependency to get item and check list access
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user), # Need user ID for completed_by
 ):
     """
@@ -140,7 +141,7 @@ async def update_item(
 
 
 @router.delete(
-    "/items/{item_id}", # Operate directly on item ID
+    "/lists/{list_id}/items/{item_id}", # Nested under lists
     status_code=status.HTTP_204_NO_CONTENT,
     summary="Delete Item",
     tags=["Items"],
@@ -149,10 +150,11 @@ async def update_item(
     }
 )
 async def delete_item(
-    item_id: int, # Item ID from path
+    list_id: int,
+    item_id: int,
     expected_version: Optional[int] = Query(None, description="The expected version of the item to delete for optimistic locking."),
     item_db: ItemModel = Depends(get_item_and_verify_access), # Use dependency to get item and check list access
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user), # Log who deleted it
 ):
     """

be/app/api/v1/endpoints/lists.py

@@ -5,7 +5,7 @@ from typing import List as PyList, Optional # Alias for Python List type hint
 from fastapi import APIRouter, Depends, HTTPException, status, Response, Query # Added Query
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.database import get_db
+from app.database import get_transactional_session
 from app.auth import current_active_user
 from app.models import User as UserModel
 from app.schemas.list import ListCreate, ListUpdate, ListPublic, ListDetail
@@ -40,7 +40,7 @@ router = APIRouter()
 )
 async def create_list(
     list_in: ListCreate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -61,7 +61,6 @@ async def create_list(
 
     try:
         created_list = await crud_list.create_list(db=db, list_in=list_in, creator_id=current_user.id)
-        await db.commit() # Ensure the transaction is committed
         logger.info(f"List '{created_list.name}' (ID: {created_list.id}) created successfully for user {current_user.email}.")
         return created_list
     except DatabaseIntegrityError as e:
@@ -87,12 +86,12 @@ async def create_list(
 
 @router.get(
     "", # Route relative to prefix "/lists"
-    response_model=PyList[ListPublic], # Return a list of basic list info
+    response_model=PyList[ListDetail], # Return a list of detailed list info including items
     summary="List Accessible Lists",
     tags=["Lists"]
 )
 async def read_lists(
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
     # Add pagination parameters later if needed: skip: int = 0, limit: int = 100
 ):
@@ -114,7 +113,7 @@ async def read_lists(
 )
 async def read_list(
     list_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -139,7 +138,7 @@ async def read_list(
 async def update_list(
     list_id: int,
     list_in: ListUpdate,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -177,7 +176,7 @@ async def update_list(
 async def delete_list(
     list_id: int,
     expected_version: Optional[int] = Query(None, description="The expected version of the list to delete for optimistic locking."),
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """
@@ -212,7 +211,7 @@ async def delete_list(
 )
 async def read_list_status(
     list_id: int,
-    db: AsyncSession = Depends(get_db),
+    db: AsyncSession = Depends(get_transactional_session),
     current_user: UserModel = Depends(current_active_user),
 ):
     """