app.py

@@ -442,18 +442,28 @@ def get_total_expense_for_list(list_id, start_date=None, end_date=None):
     return query.scalar() or 0
 
 
-
 def update_list_categories_from_form(shopping_list, form):
-    cat = form.get("categories")
-    shopping_list.categories.clear()
-    if cat:
+    raw_vals = form.getlist("categories") 
+    candidate_ids = set()
+
+    for v in raw_vals:
+        if not v:
+            continue
+        v = v.strip()
         try:
-            cid = int(cat)
-            cats = Category.query.filter(Category.id == cid).all()
-            shopping_list.categories.extend(cats)
+            candidate_ids.add(int(v))
+            continue
         except ValueError:
             pass
 
+        cat = Category.query.filter(func.lower(Category.name) == v.lower()).first()
+        if cat:
+            candidate_ids.add(cat.id)
+    shopping_list.categories.clear()
+    if candidate_ids:
+        cats = Category.query.filter(Category.id.in_(candidate_ids)).all()
+        shopping_list.categories.extend(cats)
+
 
 def generate_share_token(length=8):
     return secrets.token_hex(length // 2)