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

From: Jonathan Nieder <[email-masked]>
Date: Fri, 14 Nov 2014 15:21:07 -0800

Hi,

Mike Blume wrote:

> 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