05/22 Enhance codes and fix bugs 2

app/__init__.py

@@ -110,7 +110,7 @@ def create_app(config_name: str = 'development') -> Flask:
 
     @login_manager.user_loader
     def load_user(user_id):
-        return User.query.get(int(user_id))
+        return db.session.get(User, int(user_id))
 
     # Blueprints
     from .routes.auth import auth_bp
@@ -226,7 +226,12 @@ def create_app(config_name: str = 'development') -> Flask:
             id='token_blacklist_cleanup',
             replace_existing=True,
         )
-        scheduler.start()
+        # In Flask debug mode the Werkzeug reloader spawns two processes.
+        # WERKZEUG_RUN_MAIN == 'true' only in the child (the actual server),
+        # so we skip the scheduler in the parent reloader to avoid duplicate jobs.
+        import os
+        if not app.debug or os.environ.get('WERKZEUG_RUN_MAIN') == 'true':
+            scheduler.start()
 
     # ── Production safety checks ───────────────────────────────────────────────
     # Warn loudly at startup when running in production with settings that are