mosca collapses when directly closing browser which runs mqtt client

[simonxuhao]

Steps to reproduce the bug:

1. Install mosca
   npm install mosca bunyan

2. start mosca
   mosca -v --http-port 8888 | bunyan

3. open mqtt.io in a browser window, set last will topic to 'abc123' and last will message, connect to the broker and subscribe to topic 'abc123', publish a message

4. directly shutdown the browser, mosca broker goes crazy:

[2014-03-04T07:30:00.896Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.898Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.899Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.899Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.900Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.900Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.903Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.903Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.905Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.905Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.906Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.906Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.907Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.907Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.908Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.908Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.909Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.909Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.910Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.911Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
[2014-03-04T07:30:00.911Z] WARN: mosca/4232 on Arch: Not connected (client=kRZB3Q0CGByl5DO2MG3Vc)
[2014-03-04T07:30:00.911Z] INFO: mosca/4232 on Arch: delivering last will (client=kRZB3Q0CGByl5DO2MG3Vc, willTopic=abc123)
....
....

and quits

The issue is 100% reproducible on Chrome and IE11. Didn't try Firefox.

[email protected] ../node_modules/bunyan
├── [email protected]
└── [email protected]

[email protected] ../node_modules/mosca
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected] ([email protected])
├── [email protected] ([email protected])
├── [email protected]
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected])
├── [email protected]
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected])
├── [email protected]
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected])
└── [email protected] ([email protected], [email protected])

[mcollina]

This is a very bad bug. I never tested putting the will on the same topic of the device is subscribed.

I'll have a look at it. However it is very important the last part of the stacktrace before it quits. Can you add it?

[mcollina]

Confirmed, there is an infinite loop when delivering the last will.
I'm not sure why this is triggered only by the MQTT over Websocket thing.

[mcollina]

Can you please try https://github.com/mcollina/mosca/compare/no-will-infinite-loop and see if it works for you? It worked for me.

[simonxuhao]

Tested on mqtt.io with all combinations of Last-Will QoS Last-Will Retain, it worked fine.

[2014-03-05T02:11:13.766Z] INFO: mosca/356 on Arch: delivering last will (client=JLq2lQlZHdOrEfsmLNSxE, willTopic=abc123)
[2014-03-05T02:11:13.767Z] INFO: mosca/356 on Arch: unsubscribed (client=JLq2lQlZHdOrEfsmLNSxE, topic=abc123)
[2014-03-05T02:11:13.772Z] INFO: mosca/356 on Arch: closed (client=JLq2lQlZHdOrEfsmLNSxE)

[mcollina]

Released as 0.17.5.

Thanks!