Fix user-status endpoint: resolve TypeError from unhashable User objects in deduplication logic

backend/app/main.py

@@ -89,16 +89,44 @@ def get_user_statuses(session: Session = Depends(get_session), current_user: Use
         dept_statement = select(User).where(User.departments.any(Department.id.in_(dept_ids)))
         department_users = session.exec(dept_statement).all()
     
-    # Get users with existing private chats (either as sender or receiver)
-    chat_partners_statement = select(User).where(
-        (User.id == DirectMessage.sender_id) | (User.id == DirectMessage.receiver_id)
-    ).where(
+    # Get users with existing private chats
+    # Find all direct messages where current user is sender or receiver
+    dm_statement = select(DirectMessage).where(
         (DirectMessage.sender_id == current_user.id) | (DirectMessage.receiver_id == current_user.id)
-    ).distinct()
-    chat_partners = session.exec(chat_partners_statement).all()
+    )
+    direct_messages = session.exec(dm_statement).all()
+    
+    # Extract unique user IDs (excluding current user)
+    chat_partner_ids = set()
+    for dm in direct_messages:
+        if dm.sender_id != current_user.id:
+            chat_partner_ids.add(dm.sender_id)
+        if dm.receiver_id != current_user.id:
+            chat_partner_ids.add(dm.receiver_id)
+    
+    # Get chat partner users
+    if chat_partner_ids:
+        chat_partners_statement = select(User).where(User.id.in_(chat_partner_ids))
+        chat_partners = session.exec(chat_partners_statement).all()
+    else:
+        chat_partners = []
+    
+    # Combine and deduplicate users by ID
+    all_user_ids = set()
+    all_users = []
+    
+    # Add department users
+    for user in department_users:
+        if user.id not in all_user_ids:
+            all_user_ids.add(user.id)
+            all_users.append(user)
+    
+    # Add chat partners
+    for user in chat_partners:
+        if user.id not in all_user_ids:
+            all_user_ids.add(user.id)
+            all_users.append(user)
     
-    # Combine and deduplicate users
-    all_users = list(set(department_users + chat_partners))
     # Remove current user from the list
     all_users = [user for user in all_users if user.id != current_user.id]