The `ShellBolt` can handle the "error" command, as shown in this file in Storm source code:
But, `ShellSpout` does not actually have a handler for "error".
The symptoms a multi-lang user will see here is that if their Spout throws an error and their multi-lang implementation sends an "error" command up to the ShellSpout, the ShellSpout will respond saying that it doesn't recognize the "error" command, and thus it will crash (while swallowing the exception thrown by the underlying multi-lang component).
I am about to open a PR on Github that fixes this.
Originally reported on the streamparse project in this Github issue: