Re: [PATCH] t6026-merge-attr: wait for process to release trash directory

From: Jeff King <peff@peff.net>
Date: Sep 8, 2016, 08:27 UTC
Message-ID: <20160908082713.sgzp2evbvzuthdb4@sigill.intra.peff.net>
In-Reply-To: <alpine.DEB.2.20.1609081002490.129229@virtualbox>

On Thu, Sep 08, 2016 at 10:05:58AM +0200, Johannes Schindelin wrote:

Show 26 quoted lines

> > > 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.

Regarding my "unconditionally" above: coincidentally, I happened to be looking in lib-git-daemon.sh about an hour ago and noticed that we do indeed check "test_have_prereq PIPE" (just not near the mkfifo, of course, because we are not in a test block).

It seems to have been added by a "Johannes Schindelin". Any relation?

So yeah. It definitely would be a bad idea to use a fifo in a test that is already Windows-specific.

-Peff