mojito crash when page is reloaded and a mojit invoke() is in progress

[jithine]

Sequence -

1. User does a page action which does a mojit invoke()
2. Before invoke() is processed user does browser refresh
3. Mojito crashes

Log is captured from the moment user clicks page refresh. 1st part shows that express is detecting a request abort, but in last part of the log, the mojit's controller calls ac.done() and crashes. This is the controller action which was invoked before user did page refresh.

debug: (mojito-dispatcher): Dispatcher created
info: serving locales from cache
Error: Request aborted
    at IncomingMessage.onReqAborted (/home/jithine/g11n_self_serve/node_modules/express/node_modules/connect/node_modules/multiparty/index.js:131:17)
    at IncomingMessage.EventEmitter.emit (events.js:92:17)
    at abortIncoming (http.js:1912:11)
    at Socket.socket.onend (http.js:2004:7)
    at Socket.g (events.js:175:14)
    at Socket.EventEmitter.emit (events.js:117:20)
    at _stream_readable.js:920:16
    at process._tickCallback (node.js:419:13)
debug: (mojito-dispatcher): Dispatcher created
info: (outputhandler.server): done

Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (http.js:692:11)
    at ServerResponse.res.setHeader (/home/jithine/g11n_self_serve/node_modules/express/node_modules/connect/lib/patch.js:63:22)
    at ServerResponse.<anonymous> (/home/jithine/g11n_self_serve/node_modules/express/node_modules/connect/lib/patch.js:80:14)
    at Array.forEach (native)
    at ServerResponse.res.writeHead (/home/jithine/g11n_self_serve/node_modules/express/node_modules/connect/lib/patch.js:79:28)
    at Object.OutputHandler._writeHeaders (/home/jithine/g11n_self_serve/node_modules/mojito/lib/output-handler.server.js:133:26)
    at Object.OutputHandler.done (/home/jithine/g11n_self_serve/node_modules/mojito/lib/output-handler.server.js:59:14)
    at Object.ActionContext.done (/home/jithine/g11n_self_serve/node_modules/mojito/lib/app/autoload/action-context.common.js:532:38)
    at /home/jithine/g11n_self_serve/mojits/TaskList/controller.server.js:386:20
    at /home/jithine/g11n_self_serve/mojits/TaskList/models/model.server.js:80:21
ss [jithine@firedesire g11n_self_serve]$

[aljimenez]

Seems like _writeHeaders is getting called after the res object has been closed: (https://github.com/yahoo/mojito/blob/0d36bf1bbe9b851f34eaca1490886a52ec1f9818/lib/output-handler.server.js#L125)