Hi Peff & Junio, On Wed, 7 Sep 2016, Jeff King wrote: > On Wed, Sep 07, 2016 at 11:39:57AM -0700, Junio C Hamano wrote: > > > > Can we do some signaling with fifos to tell the hook when it is safe to > > > exit? Then we would just need to `wait` for its parent process. > > > > Is fifo safe on Windows, though? > > No clue. We seem to use mkfifo unconditionally in lib-daemon, but > perhaps people do not run that test on Windows. Other invocations seem > to be protected by the PIPE prerequisite. But... AFAICT we do not use mkfifo on Windows. Let's see what t/test-lib.sh has to say about the matter: test_lazy_prereq PIPE ' # test whether the filesystem supports FIFOs case $(uname -s) in CYGWIN*|MINGW*) false ;; *) rm -f testfifo && mkfifo testfifo ;; esac ' So there you go. The reason it is disabled is that Cygwin/MSYS2 do have a concept of a FIFO. But `git.exe` won't be able to access such a FIFO because it is emulated by the POSIX emulation layer, which Git cannot access. > > With v2 that explicitly kills, I guess we can make the sleep longer > > without slowing down in the optimistic case? > > Yeah, I think the v2 one is non-racy (I thought at first we might race > with the "echo", but it should be synchronous; the hook will not exit > until we have written the pid file, and git will not exit until the hook > is done running). Please note that Hannes and I discussed this (as I originally suggested to increase it to 10 seconds, and Hannes rightfully pointed out that we would have to change the script name, too, as it says sleep-one-second.sh, and that would have made the patch less readable) and we came to the same conclusion: it's not necessary. Ciao, Dscho