State Channels: Unhandled 'error' event

[Kalovelo]

It is stated here that you can handle 'error' event. however, there's not a documented way on how to handle that specific case.

Example errors I'd like to handle

here I'd like to retry the connection:

Error handling incoming message:
[Object: null prototype] {
  channel_id: null,
  error: [Object: null prototype] {
    code: 3,
    data: [ [Object: null prototype] ],
    message: 'Rejected',
    request: [Object: null prototype] {}
  },
  id: null,
  jsonrpc: '2.0',
  version: 1
}
UnknownChannelStateError: State Channels FSM entered unknown state
    at enterState (/home//aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:17950:11)
    at handleMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18026:3)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async dequeueMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18044:7)

This is quite random:

/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18271
  state === null || state === void 0 ? void 0 : (_state$reject = state.reject) === null || _state$reject === void 0 ? void 0 : _state$reject.call(state, Object.assign(new UnexpectedChannelMessageError(`Unexpected message received:\n\n${JSON.stringify(message)}`), {
                                                                                                                                                                       ^

UnexpectedChannelMessageError: Unexpected message received:

{"jsonrpc":"2.0","method":"channels.info","params":{"channel_id":"ch_2qisVb9Rj2MWbzmCFFZDukGieUMg4nVmxQEbVrwYmJde6J56s1","data":{"event":"died"}},"version":1}
    at handleUnexpectedMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18271:168)
    at awaitingCallContractCompletion (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:19316:10)
    at handleMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18026:45)
    at dequeueMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18044:13)
    at onMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18123:8)
    at W3CWebSocket.onmessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/@aeternity/aepp-sdk/dist/aepp-sdk.js:18211:16)
    at W3CWebSocket._dispatchEvent [as dispatchEvent] (/home/apostolos/aeternity/state-channel-demo/server/node_modules/yaeti/lib/EventTarget.js:107:17)
    at W3CWebSocket.onMessage (/home/apostolos/aeternity/state-channel-demo/server/node_modules/websocket/lib/W3CWebSocket.js:234:14)
    at WebSocketConnection.<anonymous> (/home/apostolos/aeternity/state-channel-demo/server/node_modules/websocket/lib/W3CWebSocket.js:205:19)
    at WebSocketConnection.emit (node:events:527:28) {
  wsMessage: [Object: null prototype] {
    jsonrpc: '2.0',
    method: 'channels.info',
    params: [Object: null prototype] {
      channel_id: 'ch_2qisVb9Rj2MWbzmCFFZDukGieUMg4nVmxQEbVrwYmJde6J56s1',
      data: [Object: null prototype] { event: 'died' }
    },
    version: 1
  }
}

[davidyuk]

The first part I think is fixed in #1670. I missed the emitter interface when introduced printing of that error.

Unexpected message received

Is there is a case when this error doesn't get throwed by a method it rised? I would keep 'error' events only for exceptions that can't be throwed because initiated by other peer, like the above error on handling the incomming message.

[Kalovelo]

The rejected was triggered by the node and not by the other participant - I guess that when a node is busy handling other channel connections it may reject new ones which in that case I'd like to catch it and retry the connection.