TypeError: Cannot read property 'fulfill' of undefined

[iperevozchikov]

Hello guys! I've met some hard reproduced bug few days ago It's related to message handling in rtm mode:

at RTMClient._handleMsgResponse (/.../node_modules/@slack/client/lib/clients/rtm/client.js:772:22)
at RTMClient._handlePong (/.../node_modules/@slack/client/lib/clients/rtm/client.js:606:8)
at RTMClient._handleWsMessageInternal (/.../node_modules/@slack/client/lib/clients/rtm/client.js:426:10)
at RTMClient.handleWsMessage (/.../node_modules/@slack/client/lib/clients/rtm/client.js:410:10)
at WebSocket.wrapper (/.../node_modules/@slack/client/node_modules/lodash/index.js:3095:19)
at emitTwo (events.js:106:13)
at WebSocket.emit (events.js:191:7)
at Receiver.ontext (/.../node_modules/ws/lib/WebSocket.js:841:10)
at /.../node_modules/ws/lib/Receiver.js:536:18
at Receiver.applyExtensions (/.../node_modules/ws/lib/Receiver.js:371:5)
at /.../node_modules/ws/lib/Receiver.js:508:14
at Receiver.flush (/.../node_modules/ws/lib/Receiver.js:347:3)
at Receiver.finish (/.../node_modules/ws/lib/Receiver.js:541:12)
at Receiver.expectHandler (/.../node_modules/ws/lib/Receiver.js:499:31)
at Receiver.add (/.../node_modules/ws/lib/Receiver.js:103:24)
at TLSSocket.realHandler (/.../node_modules/ws/lib/WebSocket.js:825:20)
at emitOne (events.js:96:13)
at TLSSocket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:172:18)
at TLSSocket.Readable.push (_stream_readable.js:130:10)
at TLSWrap.onread (net.js:542:20)   

I did fast investigation and found possible place, that may be cause of problem: link
In that line you get responseHandler by msgId, but you do it in unsafe way, because object may return undefined value, but you expect Promise.
Used last version of SDK: 3.3.0.

[rdlh]

Same problem here!

at RTMClient._handleMsgResponse (@slack/client/lib/clients/rtm/client.js line 761 col 22) responseHandler.fulfill(res);
at RTMClient._handlePong (@slack/client/lib/clients/rtm/client.js line 595 col 8) this._handleMsgResponse(message.reply_to, null, message);
at RTMClient._handleWsMessageInternal (@slack/client/lib/clients/rtm/client.js line 415 col 10) this._handlePong(message);
at RTMClient.handleWsMessage (@slack/client/lib/clients/rtm/client.js line 399 col 10) this._handleWsMessageInternal(message.type, message);
at WebSocket.wrapper (@slack/client/node_modules/lodash/index.js line 3095 col 19) return fn.apply(thisArg, arguments);
at WebSocket.emit (events.js line 110 col 17)
at Receiver.ontext (@slack/client/node_modules/ws/lib/WebSocket.js line 841 col 10) self.emit('message', data, flags);
at <unknown> (@slack/client/node_modules/ws/lib/Receiver.js line 536 col 18) self.ontext(messageBuffer.toString('utf8'), {masked: state.masked, buffer: messageBuffer});
at Receiver.applyExtensions (@slack/client/node_modules/ws/lib/Receiver.js line 371 col 5) callback(null, messageBuffer);
at <unknown> (@slack/client/node_modules/ws/lib/Receiver.js line 508 col 14) self.applyExtensions(packet, state.lastFragment, state.compressed, function(err, buffer) {
at Receiver.flush (@slack/client/node_modules/ws/lib/Receiver.js line 347 col 3) handler(function() {
at Receiver.opcodes.1.finish (@slack/client/node_modules/ws/lib/Receiver.js line 541 col 12) this.flush();
at Receiver.expectHandler (@slack/client/node_modules/ws/lib/Receiver.js line 499 col 31)  opcodes['1'].finish.call(self, null, data);
at Receiver.add (@slack/client/node_modules/ws/lib/Receiver.js line 103 col 24) this.expectHandler.call(this, bufferForHandler);
at TLSSocket.realHandler (@slack/client/node_modules/ws/lib/WebSocket.js line 825 col 20)  self._receiver.add(data);
at TLSSocket.emit (events.js line 107 col 17)

[ghost]

The PR above will fix this.

It should, in theory, be very hard to get to that state. Any extra info on how it happened?