🎉 Feat(docs): Added new error handling documentation and roadmap images

backend/app.py

@@ -148,7 +148,7 @@ login_manager.login_message_category = "info"
 @login_manager.user_loader
 def load_user(user_id):
     """
-    Robuster User-Loader mit Error-Handling für Schema-Probleme.
+    Robuster User-Loader mit verbessertem Error-Handling für Schema-Probleme.
     """
     try:
         # user_id von Flask-Login ist immer ein String - zu Integer konvertieren
@@ -169,34 +169,74 @@ def load_user(user_id):
             # Schema-Problem - versuche manuelle Abfrage
             app_logger.warning(f"Schema-Problem beim User-Load für ID {user_id_int}: {str(db_error)}")
             
-            # Manuelle Abfrage nur mit Basis-Feldern
+            # Erweiterte manuelle Abfrage mit allen wichtigen Feldern
             try:
                 result = db_session.execute(
-                    text("SELECT id, email, password_hash, name, role, active FROM users WHERE id = :user_id"),
+                    text("""SELECT id, email, username, password_hash, name, role, active, 
+                           created_at, last_login, updated_at, settings, department, 
+                           position, phone, bio, last_activity 
+                           FROM users WHERE id = :user_id"""),
                     {"user_id": user_id_int}
                 ).fetchone()
                 
                 if result:
-                    # Manuell User-Objekt erstellen
+                    # Manuell User-Objekt erstellen mit robuster Tupel-Behandlung
                     user = User()
-                    user.id = result[0]
-                    user.email = result[1] if len(result) > 1 else f"user_{user_id_int}@system.local"
-                    user.password_hash = result[2] if len(result) > 2 else ""
-                    user.name = result[3] if len(result) > 3 else f"User {user_id_int}"
-                    user.role = result[4] if len(result) > 4 else "user"
-                    user.active = result[5] if len(result) > 5 else True
                     
-                    # Standard-Werte für fehlende Felder
-                    user.username = getattr(user, 'username', user.email.split('@')[0])
-                    user.created_at = getattr(user, 'created_at', datetime.now())
-                    user.last_login = getattr(user, 'last_login', None)
-                    user.updated_at = getattr(user, 'updated_at', datetime.now())
+                    # Basis-Felder (immer vorhanden)
+                    user.id = result[0] if len(result) > 0 else user_id_int
+                    user.email = result[1] if len(result) > 1 and result[1] else f"user_{user_id_int}@system.local"
+                    user.username = result[2] if len(result) > 2 and result[2] else user.email.split('@')[0]
+                    user.password_hash = result[3] if len(result) > 3 and result[3] else ""
+                    user.name = result[4] if len(result) > 4 and result[4] else f"User {user_id_int}"
+                    user.role = result[5] if len(result) > 5 and result[5] else "user"
+                    user.active = result[6] if len(result) > 6 and result[6] is not None else True
                     
+                    # Erweiterte Felder (optional)
+                    user.created_at = result[7] if len(result) > 7 and result[7] else datetime.now()
+                    user.last_login = result[8] if len(result) > 8 else None
+                    user.updated_at = result[9] if len(result) > 9 and result[9] else datetime.now()
+                    user.settings = result[10] if len(result) > 10 else None
+                    user.department = result[11] if len(result) > 11 else None
+                    user.position = result[12] if len(result) > 12 else None
+                    user.phone = result[13] if len(result) > 13 else None
+                    user.bio = result[14] if len(result) > 14 else None
+                    user.last_activity = result[15] if len(result) > 15 else datetime.now()
+                    
+                    app_logger.info(f"User {user_id_int} erfolgreich über manuelle Abfrage geladen")
                     db_session.close()
                     return user
                     
             except Exception as manual_error:
                 app_logger.error(f"Auch manuelle User-Abfrage fehlgeschlagen: {str(manual_error)}")
+                
+                # Letzter Fallback: Minimale User-Daten erstellen
+                try:
+                    # Prüfen ob User überhaupt existiert
+                    exists_result = db_session.execute(
+                        text("SELECT COUNT(*) FROM users WHERE id = :user_id"),
+                        {"user_id": user_id_int}
+                    ).fetchone()
+                    
+                    if exists_result and exists_result[0] > 0:
+                        # User existiert, aber Schema ist korrupt - Notfall-User erstellen
+                        user = User()
+                        user.id = user_id_int
+                        user.email = f"user_{user_id_int}@system.local"
+                        user.username = f"user_{user_id_int}"
+                        user.password_hash = ""
+                        user.name = f"User {user_id_int}"
+                        user.role = "user"
+                        user.active = True
+                        user.created_at = datetime.now()
+                        user.last_login = None
+                        user.updated_at = datetime.now()
+                        
+                        app_logger.warning(f"Notfall-User-Objekt für ID {user_id_int} erstellt")
+                        db_session.close()
+                        return user
+                except Exception as fallback_error:
+                    app_logger.error(f"Auch Fallback-User-Erstellung fehlgeschlagen: {str(fallback_error)}")
             
             db_session.close()
             return None