node crashes when Stream.on('readable', ...) on Duplex

[alexlamsl]

A simple way to reproduce this issue:

~$ node
> process.stdout instanceof require('stream').Duplex
true
> process.stdout.on('readable', function() {console.log('stdout')})

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: This socket is closed.
    at WriteStream.Socket._write (net.js:618:19)
    at doWrite (_stream_writable.js:211:10)
    at writeOrBuffer (_stream_writable.js:201:5)
    at WriteStream.Writable.write (_stream_writable.js:172:11)
    at WriteStream.Socket.write (net.js:596:40)
    at finish (repl.js:291:27)
    at repl.js:251:15
    at REPLServer.self.eval (repl.js:122:7)
    at Interface. (repl.js:239:12)
    at Interface.EventEmitter.emit (events.js:95:17)

~$

Note that node crashes - and this is reproducible for normal mode as well as shell mode.

[isaacs]

Ah, that's weird.

Note: process.stdout is not actually "readable", so the bug here is that it even tries to read from it.

[alexlamsl]

I agree whole-heartedly - except this is a Duplex, which makes process.stdout instanceof require('stream').Readable === true

Or have I mistaken about how Duplex should behave?

[isaacs]

Well, it's a Socket, which is a child of Duplex, because Sockets are sometimes readable and sometimes writable and sometimes both or neither. But just because it's an instanceof Readable doesn't necessarily mean that you can read from it. After all,

> process.stdout.readable
false

[isaacs]

I'm not able to reproduce this on latest v0.10. Can you? I'm guessing it got fixed somehow?

[alexlamsl]

I am on 0.10.1 (and Windows):

C:\nodejs>node
> process.version
'v0.10.1'
> process.stdout instanceof require('stream').Readable
true
> process.stdout.readable
false
>

So you are saying I should use stream.readable instead of instanceof?

[TooTallNate]

yes

[alexlamsl]

Thanks for the clarification :)