{ "rules_require_product_2" : {
    "LABEL" : "Require Product 2",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "commerce_order", "rules", "commerce_cart" ],
    "ON" : [ "commerce_cart_product_add" ],
    "IF" : [
      { "NOT commerce_order_contains_product" : {
          "commerce_order" : [ "commerce-order" ],
          "product_id" : "PROD-02",
          "operator" : "=",
          "value" : "1"
        }
      }
    ],
    "DO" : [
      { "drupal_message" : {
          "message" : "Sorry, in order to add that to your cart, you must add Product #2",
          "type" : "warning"
        }
      },
      { "LOOP" : {
          "USING" : { "list" : [ "commerce-order:commerce-line-items" ] },
          "ITEM" : { "list_item" : "Current list item" },
          "DO" : [
            { "list_remove" : {
                "list" : [ "commerce-order:commerce-line-items" ],
                "item" : [ "list-item" ]
              }
            }
          ]
        }
      }
    ]
  }
}