Re: [PATCH v4] Allow TTY tests to run under recent Mac OS

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Nov 14, 2014, 23:21 UTC
Message-ID: <20141114232106.GA6527@google.com>
In-Reply-To: <1415995993-70879-1-git-send-email-blume.mike@gmail.com>

Hi,

Mike Blume wrote:

Show 5 quoted lines

> TTY tests were previously skipped on all Mac OS systems because of a
> bug where reading from pty master occasionally hung. This bug has since
> been found not to be reproducible under Mac OS 10.9 and 10.10.1.
>
> Therefore, run TTY tests under Mac OS 10.9 (Mavericks) and higher.

*puzzled* Testing on Yosemite with the following script[1]

	perl -MIO::Pty -MFile::Copy -e '
	       for (my $i = 0;; $i++) {
		       my $master = new IO::Pty;
		       my $slave = $master->slave;
		       if (fork == 0) {
			       close $master or die "close: $!";
			       open STDOUT, ">&", $slave or die "dup2: $!";
			       close $slave or die "close: $!";
			       exec("echo", "hi", $i) or die "exec: $!";
		       }
		       close $slave or die "close: $!";
		       copy($master, \*STDOUT) or die "copy: $!";
		       close $master or die "close: $!";
		       wait;
	       }
	'

still seems to hang eventually (after 61 iterations when my officemate tried it), reproducing the bug.

Do you get a different result?

The bug was originally found in an autobuilder that would run the test suite when new versions were pushed to check for regressions. Even if the hang only happened 0.1% of the time, that would get the autobuilder stuck after a while, which was how the problem got noticed.

Thanks, Jonathan

[1] https://rt.cpan.org/Public/Bug/Display.html?id=65692