Extra error handling for node pools that don't match instance manager pattern. (#1149)

Author: nat-henderson

google/resource_container_node_pool.go

@@ -368,9 +368,12 @@ func flattenNodePool(d *schema.ResourceData, config *Config, np *container.NodeP
 	for _, url := range np.InstanceGroupUrls {
 		// retrieve instance group manager (InstanceGroupUrls are actually URLs for InstanceGroupManagers)
 		matches := instanceGroupManagerURL.FindStringSubmatch(url)
+		if len(matches) < 4 {
+			return nil, fmt.Errorf("Error reading instance group manage URL '%q'", url)
+		}
 		igm, err := config.clientCompute.InstanceGroupManagers.Get(matches[1], matches[2], matches[3]).Do()
 		if err != nil {
-			return nil, fmt.Errorf("Error reading instance group manager returned as an instance group URL: %s", err)
+			return nil, fmt.Errorf("Error reading instance group manager returned as an instance group URL: %q", err)
 		}
 		size += int(igm.TargetSize)
 	}