Re: [msysGit] upload-pack timing issue on windows?

On Montag, 23. August 2010, Erik Faye-Lund wrote:

- The culprit seems to be our poll-emulation. My understanding is that
poll() was called by create_pack_file() in upload-pack.c with nfds=1
(it's 2 until one of the fds are closed) when there's no data
available in the pipe. Since our poll() always returns POLLIN when
nfds=1, the check for xread(...) == 0 further down in
create_pack_file() cause the fd to be closed, leading to an error on
the client-side.
-  Just removing the nfds=1-hack works for me, but I'm suspecting the
nfds=1-hack is there for some socket-reason. So instead I've replaced
our poll-emulation with gnulib's in my branch (with a couple of
patches on top), and it seems to do the trick for me. I still haven't
tested it heavily, though.

The nfds == 1 hack is an "optimization": When only one channel must be 
observed, then we can let (x)read() wait for data instead of doing it inside 
poll() in some way.

I'm not happy with our poll emulation because it contains a busy-loop. 
Gnulib's version looks quite capable, but I haven't studied it in detail. 
Until then, I trust that it does the right thing.

--Hannes