REPL lock-up handling UDP stream

[thenwithexpandedwingshesteershisflight]

hi, I'm parsing a stream from the iphone app Sensor Data, which streams the iphone's sensor data over a port via UDP.

here's the code:

https://gist.github.com/3066388

it works, but the REPL is completely locking up sometimes (can't ctrl+d out) and I can't work out the why.

[Zach Tellman]

Nothing you're doing should be executing anything on the REPL thread,
so my guess is that maybe the data structure that is being printed is
just too large. Make sure you're only printing the count, and see if
the problem persists.

If it does, post a jstack dump of the REPL or swank process while it's hung.

Zach

[thenwithexpandedwingshesteershisflight]

it hangs in seemingly unrelated operations to Aleph/Lamina, even when the stream isn't being handled so maybe it's netty ?
Here's what I did:

lein repl
jps returns 2 processes for that repl

then I evaluated code here:
https://gist.github.com/3068925
- requiring a namespace, entering that namespace, creating channels, then I defined a function ready to receive-all on my channel (which has worked before), then it hung - jstacks for the 2 processes are below
- but that's not a reproducable scenario - I just tried the same again and no hang

[Colin Jones]

Which preview release of lein2 are you using? preview4 or earlier? There were some race-condition bugs fixed in REPLy after then that would definitely explain it, and the stacktrace line numbers in REPLy makes me suspect that you might be on preview4. 

Can you try upgrading lein2 to the latest preview, and see if you can still reproduce it?

- Colin

[thenwithexpandedwingshesteershisflight]

Leiningen 2.0.0-preview4 on Java 1.7.0_04 Java HotSpot(TM) 64-Bit Server VM

just upgraded to preview7 and no hanging - thanks!!

[Zach Tellman]

Glad to hear it. Colin, thanks for jumping in, I was completely at a loss.

Zach