Work around Msys weakness in Testlib.pm's command_like()

When output of IPC::Run::run () is redirected to scalar references, in
certain circumstances the Msys perl does not correctly detect that the
end of file has been seen, making the test hang indefinitely. One such
circumstance is when the command is 'pg_ctl start', and such a change
was made in commit f13ea95f9e. The workaround, which only applies on
MSys, is to redirect the output to temporary files and then read them in
when the process has finished.

Patch by me, reviewed and tweaked by Tom Lane.

src/bin/pg_ctl/t/001_start_stop.pl

@@ -32,9 +32,17 @@ else
 	print $conf "listen_addresses = '127.0.0.1'\n";
 }
 close $conf;
-command_like([ 'pg_ctl', 'start', '-D', "$tempdir/data",
-	'-l', "$TestLib::log_path/001_start_stop_server.log" ],
-	qr/done.*server started/s, 'pg_ctl start');
+my $ctlcmd = [ 'pg_ctl', 'start', '-D', "$tempdir/data",
+			   '-l', "$TestLib::log_path/001_start_stop_server.log" ];
+if ($Config{osname} ne 'msys')
+{
+	command_like($ctlcmd, qr/done.*server started/s, 'pg_ctl start');
+}
+else
+{
+	# use the version of command_like that doesn't hang on Msys here
+	command_like_safe($ctlcmd, qr/done.*server started/s, 'pg_ctl start');
+}
 
 # sleep here is because Windows builds can't check postmaster.pid exactly,
 # so they may mistake a pre-existing postmaster.pid for one created by the

src/test/perl/TestLib.pm

@@ -37,6 +37,7 @@ our @EXPORT = qw(
   program_version_ok
   program_options_handling_ok
   command_like
+  command_like_safe
   command_fails_like
 
   $windows_os
@@ -300,6 +301,24 @@ sub command_like
 	like($stdout, $expected_stdout, "$test_name: matches");
 }
 
+sub command_like_safe
+{
+	# Doesn't rely on detecting end of file on the file descriptors,
+	# which can fail, causing the process to hang, notably on Msys
+	# when used with 'pg_ctl start'
+	my ($cmd, $expected_stdout, $test_name) = @_;
+	my ($stdout, $stderr);
+	my $stdoutfile = File::Temp->new();
+	my $stderrfile = File::Temp->new();
+	print("# Running: " . join(" ", @{$cmd}) . "\n");
+	my $result = IPC::Run::run $cmd, '>', $stdoutfile, '2>', $stderrfile;
+	$stdout = slurp_file($stdoutfile);
+	$stderr = slurp_file($stderrfile);
+	ok($result, "$test_name: exit code 0");
+	is($stderr, '', "$test_name: no stderr");
+	like($stdout, $expected_stdout, "$test_name: matches");
+}
+
 sub command_fails_like
 {
 	my ($cmd, $expected_stderr, $test_name) = @_;