Folks:

I just ran into a problem where I did a "darcs push user@host" and it  
"hung".  After a few minutes (instead of waiting I went to do other  
stuff), I realized that the underlying ssh connection must be blocked.

I tried it -- "ssh user@host" -- and sure enough the Windows putty  
ssh posted a warning message to stderr and blocked after asking  
"Store key in cache? (y/n)".

I've noticed that this is a frequent problem for new users of  
darcs.  If anyone is having trouble using darcs over ssh, the first  
step is always to tell them to invoke the equivalent ssh command on  
the command-line so that they can see the stderr.

Brian Warner pointed out to me that if darcs simply passed any stderr  
from the call to ssh back to darcs's stderr, then this would happen  
automatically and new users (as well as experienced users like me)  
would be able to diagnose their problems more quickly.

Regards,

Zooko