proton -r dies with "EMFILE, Too many open files" after a long time (leak)

[tomyan]

When proton is set to reload changes immediately (the -r option), it sits with the following output for a long time (perhaps a couple of days of intermittent hacking on a project):

mac:~/node-projects/use.no.de> proton -r
webapp started on 0.0.0.0:8000

It then dies with the following error:

/Users/thomasyandell/node-projects/proton.js/lib/proton.js:104
    var pipe    = net_binding.socketpair(),
                              ^
Error: EMFILE, Too many open files
    at new <anonymous> (/Users/thomasyandell/node-projects/proton.js/lib/proton.js:104:31)
    at Server.<anonymous> (/Users/thomasyandell/node-projects/proton.js/lib/proton.js:140:21)
    at Server.emit (events.js:64:17)
    at IOWatcher.callback (net.js:950:12)

This must be the parent process leaking handles, which should be fairly easy to track down and fix. This occurs with the https://github.com/usenode/use.no.de project, but I think Richard said it also happens on other sites.