fix(cart): recover from stale menu items at checkout

cafe-management-sys/src/components/CartContext.jsx

@@ -8,6 +8,7 @@ import {
     generateCartItemId,
     cartTotals,
     buildOrderItems,
+    staleItemId,
 } from '../utils/cartPricing';
 
 const CartContext = createContext();
@@ -181,7 +182,19 @@ export const CartProvider = ({ children }) => {
 
             setOrderError(errorMessage);
             setOrderConfirmation(null);
-            throw new Error(errorMessage);
+            // A stored cart line may reference a menu item that no longer exists
+            // (e.g. deleted after a menu/DB change). Drop just that line so a
+            // retry succeeds and the customer can finish checkout.
+            const staleId = staleItemId(errorMessage);
+            if (staleId) {
+                setCartItems(prev => prev.filter((it) => it._id !== staleId));
+                setOrderError('One item in your cart is no longer available and was removed.');
+            }
+            throw new Error(
+                staleId
+                    ? 'An item in your cart is no longer available and was removed. Please review and try again.'
+                    : errorMessage
+            );
         } finally {
             setIsLoading(false);
         }

cafe-management-sys/src/utils/cartPricing.js

@@ -64,6 +64,12 @@ export const generateCartItemId = (id, size, options) =>
     .map(([key, value]) => `${key}:${value}`)
     .join('|')}`;
 
+/** Extracts the menu id from a server 'Menu item not found: <uuid>' error. */
+export const staleItemId = (message = '') => {
+  const m = String(message).match(/Menu item not found: ([0-9a-f-]{8,})/i);
+  return m ? m[1] : null;
+};
+
 /** Shape cart lines into the server's `POST /orders` item contract. */
 export const buildOrderItems = (items = []) =>
   items.map((item) => ({

cafe-management-sys/src/utils/cartPricing.test.js

@@ -9,6 +9,7 @@ import {
   estimateTotals,
   generateCartItemId,
   buildOrderItems,
+  staleItemId,
 } from './cartPricing';
 
 const legacy = { _id: 'm1', price: { medium: 100, large: 150 }, quantity: 2, selectedSize: 'large' };
@@ -96,4 +97,11 @@ describe('cartPricing', () => {
       specialInstructions: 'no ice',
     });
   });
+
+  it('staleItemId extracts a stale menu id from the server error', () => {
+    expect(staleItemId('Menu item not found: 55ffe79f-c6de-4a58-8bf3-7db2992c8fdf'))
+      .toBe('55ffe79f-c6de-4a58-8bf3-7db2992c8fdf');
+    expect(staleItemId('Something else')).toBeNull();
+    expect(staleItemId('')).toBeNull();
+  });
 });