购物车加入错误

@@ -53,16 +53,16 @@ class Cart extends Api
             }
             $model->where('id', $cart['id'])->delete();
         }
-        $spec_sku = new Litestoregoodsspec();
+        $spec_sku  = new Litestoregoodsspec();
+        $spec_info = $spec_sku->where('goods_spec_id', $sku_id)->find();
         if ($cart) {
-            $spec_sku->where('goods_spec_id', $sku_id)->find();
-            if ($spec_sku['stock_num'] + $cart['number'] < $number) {
+
+            if ($spec_info['stock_num'] + $cart['number'] < $number) {
                 $this->error('库存不足');
             }
             $cart->setInc('number', $number);
         } else {
-            $spec_sku->where('goods_spec_id', $sku_id)->find();
-            if ($spec_sku['stock_num'] < $number) {
+            if ($spec_info['stock_num'] < $number) {
                 $this->error('库存不足');
             }
             $data['number'] = $number;