Re: [PATCH] Fix race and deadlock when sending pack

Paul Serice [off-list ref] writes:

The best way to reproduce the problem is to locally clone your
repository.  When you perform a push, git-send-pack will directly set
up pipes connected to stdin and stdout of git-receive-pack.  You
should then set up hook/post-update or hook/update to try to write
lots of text to stdout.  (You want to use the local protocol because
ssh is robust enough to mask the worst behavior.)

My immediate reaction was "do not do it then", but you are
right.  Hooks are run after all the protocol exchanges are done,
so they should be free to throw any garbage at the other end.

It appears cpfd() seems to mostly duplicate what is in copy.c;
is there any particular reason?