From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Subject: Re: TAP tests and symlinks on Windows
To: Michael Paquier <michael@paquier.xyz>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
 =?UTF-8?Q?Juan_Jos=c3=a9_Santamar=c3=ada_Flecha?=
 <juanjo.santamaria@gmail.com>, =?UTF-8?Q?Dagfinn_Ilmari_Manns=c3=a5ker?=
 <ilmari@ilmari.org>, pgsql-hackers <pgsql-hackers@postgresql.org>
References: <20200615062319.GF52676@paquier.xyz>
 <11c4ee09-3706-5912-ffd7-dc3657de7a5e@2ndQuadrant.com>
 <20200617074434.GB118592@paquier.xyz> <20200623105527.GA1974@paquier.xyz>
 <3ebcde2b-3b78-2e5f-9249-03c709dc23dd@2ndquadrant.com>
 <20200629075616.GC330401@paquier.xyz> <20200630121328.GB67289@paquier.xyz>
 <504f09d7-d600-44ca-a32b-0ed209cc2273@2ndquadrant.com>
 <19483ac1-0f31-cfd3-8ef7-5da0ac5a5f46@2ndQuadrant.com>
 <ea68701d-0225-b457-e729-67e9fe4f41e6@2ndQuadrant.com>
 <20200714052837.GH10826@paquier.xyz>
Autocrypt: addr=andrew.dunstan@2ndQuadrant.com; prefer-encrypt=mutual;
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Message-ID: <5a0b2bea-16c1-6e24-246a-eceea5757b68@2ndQuadrant.com>
Date: Wed, 15 Jul 2020 11:04:28 -0400
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On 7/14/20 1:31 AM, Michael Paquier wrote:
> On Fri, Jul 10, 2020 at 07:58:02AM -0400, Andrew Dunstan wrote:
>> After much frustration and gnashing of teeth here's a patch that allows
>> almost all the TAP tests involving symlinks to work as expected on all
>> Windows build environments, without requiring an additional Perl module.
>> I have tested this on a system that is very similar to that running
>> drongo and fairywren, with both msys2 and MSVC builds.
> Thanks Andrew for looking at the part with MSYS.  The tests pass for
> me with MSVC.  The trick with mklink is cool.  I have not considered
> that, and the test code gets simpler.
>
> +       my $cmd = qq{mklink /j "$newname" "$oldname"};
> +       if ($Config{osname} eq 'msys')
> +       {
> +           # need some indirection on msys
> +           $cmd = qq{echo '$cmd' | \$COMSPEC /Q};
> +       }
> +       note("dir_symlink cmd: $cmd");
> +       system($cmd);
> From the quoting perspective, wouldn't it be simpler to build an array
> with all those arguments and call system() with @cmd?


This is the simplest invocation I found to be reliable on msys2 (and it
took me a long time to find). If you have a tested alternative please
let me know.


> +# Create files that look like temporary relations to ensure they are ignored
> +# in a tablespace.
> +my @tempRelationFiles = qw(t888_888 t888888_888888_vm.1);
> This variable conflicts with a previous declaration, creating a
> warning.
>
> +   skip "symlink check not implemented on Windows", 1
> +     if ($windows_os);
>     opendir(my $dh, "$pgdata/pg_tblspc") or die;
> I think that this would be cleaner with a SKIP block.


I don't understand this comment. The skip statement here is in a SKIP
block. In fact skip only works inside SKIP blocks. (perldoc Test::More
for details). Maybe you got confused by the diff format.


>
> +Portably create a symlink for a director. On Windows this creates a junction.
> +Elsewhere it just calls perl's builtin symlink.
> s/director/directory/
> s/junction/junction point/


fixed.


>
>    <para>
>      The TAP tests require the Perl module <literal>IPC::Run</literal>.
>      This module is available from CPAN or an operating system package.
> +    On Windows, <literal>Win32API::File</literal> is also required .
>    </para>
> This part should be backpatched IMO.


I will do this in  a separate backpatched commit.


>
> Some of the indentation is weird, this needs a cleanup with perltidy.


Done.


Revised patch attached.


cheers


andrew


-- 
Andrew Dunstan                https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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diff --git a/src/bin/pg_basebackup/t/010_pg_basebackup.pl b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
index 208df557b8..f674a7c94e 100644
--- a/src/bin/pg_basebackup/t/010_pg_basebackup.pl
+++ b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
@@ -211,87 +211,93 @@ $node->command_fails(
 	'pg_basebackup tar with long name fails');
 unlink "$pgdata/$superlongname";
 
-# The following tests test symlinks. Windows doesn't have symlinks, so
-# skip on Windows.
+# The following tests are for symlinks.
+
+# Move pg_replslot out of $pgdata and create a symlink to it.
+$node->stop;
+
+# Set umask so test directories and files are created with group permissions
+umask(0027);
+
+# Enable group permissions on PGDATA
+chmod_recursive("$pgdata", 0750, 0640);
+
+rename("$pgdata/pg_replslot", "$tempdir/pg_replslot")
+  or BAIL_OUT "could not move $pgdata/pg_replslot";
+dir_symlink("$tempdir/pg_replslot", "$pgdata/pg_replslot")
+  or BAIL_OUT "could not symlink to $pgdata/pg_replslot";
+
+$node->start;
+
+# Create a temporary directory in the system location and symlink it
+# to our physical temp location.  That way we can use shorter names
+# for the tablespace directories, which hopefully won't run afoul of
+# the 99 character length limit.
+my $shorter_tempdir = TestLib::tempdir_short . "/tempdir";
+dir_symlink "$tempdir", $shorter_tempdir;
+
+mkdir "$tempdir/tblspc1";
+my $realTsDir    = TestLib::perl2host("$shorter_tempdir/tblspc1");
+my $real_tempdir = TestLib::perl2host($tempdir);
+$node->safe_psql('postgres',
+	"CREATE TABLESPACE tblspc1 LOCATION '$realTsDir';");
+$node->safe_psql('postgres',
+	"CREATE TABLE test1 (a int) TABLESPACE tblspc1;");
+$node->command_ok(
+	[ 'pg_basebackup', '-D', "$real_tempdir/tarbackup2", '-Ft' ],
+	'tar format with tablespaces');
+ok(-f "$tempdir/tarbackup2/base.tar", 'backup tar was created');
+my @tblspc_tars = glob "$tempdir/tarbackup2/[0-9]*.tar";
+is(scalar(@tblspc_tars), 1, 'one tablespace tar was created');
+rmtree("$tempdir/tarbackup2");
+
+# Create an unlogged table to test that forks other than init are not copied.
+$node->safe_psql('postgres',
+	'CREATE UNLOGGED TABLE tblspc1_unlogged (id int) TABLESPACE tblspc1;');
+
+my $tblspc1UnloggedPath = $node->safe_psql('postgres',
+	q{select pg_relation_filepath('tblspc1_unlogged')});
+
+# Make sure main and init forks exist
+ok( -f "$pgdata/${tblspc1UnloggedPath}_init",
+	'unlogged init fork in tablespace');
+ok(-f "$pgdata/$tblspc1UnloggedPath", 'unlogged main fork in tablespace');
+
+# Create files that look like temporary relations to ensure they are ignored
+# in a tablespace.
+@tempRelationFiles = qw(t888_888 t888888_888888_vm.1);
+my $tblSpc1Id = basename(
+	dirname(
+		dirname(
+			$node->safe_psql(
+				'postgres', q{select pg_relation_filepath('test1')}))));
+
+foreach my $filename (@tempRelationFiles)
+{
+	append_to_file(
+		"$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename",
+		'TEMP_RELATION');
+}
+
+$node->command_fails(
+	[ 'pg_basebackup', '-D', "$tempdir/backup1", '-Fp' ],
+	'plain format with tablespaces fails without tablespace mapping');
+
+$node->command_ok(
+	[
+		'pg_basebackup',    '-D',
+		"$tempdir/backup1", '-Fp',
+		"-T$realTsDir=$real_tempdir/tbackup/tblspc1"
+	],
+	'plain format with tablespaces succeeds with tablespace mapping');
+ok(-d "$tempdir/tbackup/tblspc1", 'tablespace was relocated');
+
+# This symlink check is not supported on Windows as -l
+# doesn't work with junctions
 SKIP:
 {
-	skip "symlinks not supported on Windows", 18 if ($windows_os);
-
-	# Move pg_replslot out of $pgdata and create a symlink to it.
-	$node->stop;
-
-	# Set umask so test directories and files are created with group permissions
-	umask(0027);
-
-	# Enable group permissions on PGDATA
-	chmod_recursive("$pgdata", 0750, 0640);
-
-	rename("$pgdata/pg_replslot", "$tempdir/pg_replslot")
-	  or BAIL_OUT "could not move $pgdata/pg_replslot";
-	symlink("$tempdir/pg_replslot", "$pgdata/pg_replslot")
-	  or BAIL_OUT "could not symlink to $pgdata/pg_replslot";
-
-	$node->start;
-
-	# Create a temporary directory in the system location and symlink it
-	# to our physical temp location.  That way we can use shorter names
-	# for the tablespace directories, which hopefully won't run afoul of
-	# the 99 character length limit.
-	my $shorter_tempdir = TestLib::tempdir_short . "/tempdir";
-	symlink "$tempdir", $shorter_tempdir;
-
-	mkdir "$tempdir/tblspc1";
-	$node->safe_psql('postgres',
-		"CREATE TABLESPACE tblspc1 LOCATION '$shorter_tempdir/tblspc1';");
-	$node->safe_psql('postgres',
-		"CREATE TABLE test1 (a int) TABLESPACE tblspc1;");
-	$node->command_ok([ 'pg_basebackup', '-D', "$tempdir/tarbackup2", '-Ft' ],
-		'tar format with tablespaces');
-	ok(-f "$tempdir/tarbackup2/base.tar", 'backup tar was created');
-	my @tblspc_tars = glob "$tempdir/tarbackup2/[0-9]*.tar";
-	is(scalar(@tblspc_tars), 1, 'one tablespace tar was created');
-	rmtree("$tempdir/tarbackup2");
-
-	# Create an unlogged table to test that forks other than init are not copied.
-	$node->safe_psql('postgres',
-		'CREATE UNLOGGED TABLE tblspc1_unlogged (id int) TABLESPACE tblspc1;'
-	);
-
-	my $tblspc1UnloggedPath = $node->safe_psql('postgres',
-		q{select pg_relation_filepath('tblspc1_unlogged')});
-
-	# Make sure main and init forks exist
-	ok( -f "$pgdata/${tblspc1UnloggedPath}_init",
-		'unlogged init fork in tablespace');
-	ok(-f "$pgdata/$tblspc1UnloggedPath", 'unlogged main fork in tablespace');
-
-	# Create files that look like temporary relations to ensure they are ignored
-	# in a tablespace.
-	my @tempRelationFiles = qw(t888_888 t888888_888888_vm.1);
-	my $tblSpc1Id         = basename(
-		dirname(
-			dirname(
-				$node->safe_psql(
-					'postgres', q{select pg_relation_filepath('test1')}))));
-
-	foreach my $filename (@tempRelationFiles)
-	{
-		append_to_file(
-			"$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename",
-			'TEMP_RELATION');
-	}
-
-	$node->command_fails(
-		[ 'pg_basebackup', '-D', "$tempdir/backup1", '-Fp' ],
-		'plain format with tablespaces fails without tablespace mapping');
-
-	$node->command_ok(
-		[
-			'pg_basebackup', '-D', "$tempdir/backup1", '-Fp',
-			"-T$shorter_tempdir/tblspc1=$tempdir/tbackup/tblspc1"
-		],
-		'plain format with tablespaces succeeds with tablespace mapping');
-	ok(-d "$tempdir/tbackup/tblspc1", 'tablespace was relocated');
+	skip "symlink check not implemented on Windows", 1
+	  if ($windows_os);
 	opendir(my $dh, "$pgdata/pg_tblspc") or die;
 	ok( (   grep {
 				-l "$tempdir/backup1/pg_tblspc/$_"
@@ -300,65 +306,73 @@ SKIP:
 			} readdir($dh)),
 		"tablespace symlink was updated");
 	closedir $dh;
+}
+
+# Group access should be enabled on all backup files
+SKIP:
+{
+	skip "unix-style permissions not supported on Windows", 1
+	  if ($windows_os);
 
-	# Group access should be enabled on all backup files
 	ok(check_mode_recursive("$tempdir/backup1", 0750, 0640),
 		"check backup dir permissions");
+}
+
+# Unlogged relation forks other than init should not be copied
+my ($tblspc1UnloggedBackupPath) =
+  $tblspc1UnloggedPath =~ /[^\/]*\/[^\/]*\/[^\/]*$/g;
+
+ok(-f "$tempdir/tbackup/tblspc1/${tblspc1UnloggedBackupPath}_init",
+	'unlogged init fork in tablespace backup');
+ok(!-f "$tempdir/tbackup/tblspc1/$tblspc1UnloggedBackupPath",
+	'unlogged main fork not in tablespace backup');
 
-	# Unlogged relation forks other than init should not be copied
-	my ($tblspc1UnloggedBackupPath) =
-	  $tblspc1UnloggedPath =~ /[^\/]*\/[^\/]*\/[^\/]*$/g;
-
-	ok(-f "$tempdir/tbackup/tblspc1/${tblspc1UnloggedBackupPath}_init",
-		'unlogged init fork in tablespace backup');
-	ok(!-f "$tempdir/tbackup/tblspc1/$tblspc1UnloggedBackupPath",
-		'unlogged main fork not in tablespace backup');
-
-	# Temp relations should not be copied.
-	foreach my $filename (@tempRelationFiles)
-	{
-		ok( !-f "$tempdir/tbackup/tblspc1/$tblSpc1Id/$postgresOid/$filename",
-			"[tblspc1]/$postgresOid/$filename not copied");
-
-		# Also remove temp relation files or tablespace drop will fail.
-		my $filepath =
-		  "$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename";
-
-		unlink($filepath)
-		  or BAIL_OUT("unable to unlink $filepath");
-	}
-
-	ok( -d "$tempdir/backup1/pg_replslot",
-		'pg_replslot symlink copied as directory');
-	rmtree("$tempdir/backup1");
-
-	mkdir "$tempdir/tbl=spc2";
-	$node->safe_psql('postgres', "DROP TABLE test1;");
-	$node->safe_psql('postgres', "DROP TABLE tblspc1_unlogged;");
-	$node->safe_psql('postgres', "DROP TABLESPACE tblspc1;");
-	$node->safe_psql('postgres',
-		"CREATE TABLESPACE tblspc2 LOCATION '$shorter_tempdir/tbl=spc2';");
-	$node->command_ok(
-		[
-			'pg_basebackup', '-D', "$tempdir/backup3", '-Fp',
-			"-T$shorter_tempdir/tbl\\=spc2=$tempdir/tbackup/tbl\\=spc2"
-		],
-		'mapping tablespace with = sign in path');
-	ok(-d "$tempdir/tbackup/tbl=spc2",
-		'tablespace with = sign was relocated');
-	$node->safe_psql('postgres', "DROP TABLESPACE tblspc2;");
-	rmtree("$tempdir/backup3");
-
-	mkdir "$tempdir/$superlongname";
-	$node->safe_psql('postgres',
-		"CREATE TABLESPACE tblspc3 LOCATION '$tempdir/$superlongname';");
-	$node->command_ok(
-		[ 'pg_basebackup', '-D', "$tempdir/tarbackup_l3", '-Ft' ],
-		'pg_basebackup tar with long symlink target');
-	$node->safe_psql('postgres', "DROP TABLESPACE tblspc3;");
-	rmtree("$tempdir/tarbackup_l3");
+# Temp relations should not be copied.
+foreach my $filename (@tempRelationFiles)
+{
+	ok(!-f "$tempdir/tbackup/tblspc1/$tblSpc1Id/$postgresOid/$filename",
+		"[tblspc1]/$postgresOid/$filename not copied");
+
+	# Also remove temp relation files or tablespace drop will fail.
+	my $filepath =
+	  "$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename";
+
+	unlink($filepath)
+	  or BAIL_OUT("unable to unlink $filepath");
 }
 
+ok( -d "$tempdir/backup1/pg_replslot",
+	'pg_replslot symlink copied as directory');
+rmtree("$tempdir/backup1");
+
+mkdir "$tempdir/tbl=spc2";
+$realTsDir = TestLib::perl2host("$shorter_tempdir/tbl=spc2");
+$node->safe_psql('postgres', "DROP TABLE test1;");
+$node->safe_psql('postgres', "DROP TABLE tblspc1_unlogged;");
+$node->safe_psql('postgres', "DROP TABLESPACE tblspc1;");
+$node->safe_psql('postgres',
+	"CREATE TABLESPACE tblspc2 LOCATION '$realTsDir';");
+$realTsDir =~ s/=/\\=/;
+$node->command_ok(
+	[
+		'pg_basebackup',    '-D',
+		"$tempdir/backup3", '-Fp',
+		"-T$realTsDir=$real_tempdir/tbackup/tbl\\=spc2"
+	],
+	'mapping tablespace with = sign in path');
+ok(-d "$tempdir/tbackup/tbl=spc2", 'tablespace with = sign was relocated');
+$node->safe_psql('postgres', "DROP TABLESPACE tblspc2;");
+rmtree("$tempdir/backup3");
+
+mkdir "$tempdir/$superlongname";
+$realTsDir = TestLib::perl2host("$shorter_tempdir/$superlongname");
+$node->safe_psql('postgres',
+	"CREATE TABLESPACE tblspc3 LOCATION '$realTsDir';");
+$node->command_ok([ 'pg_basebackup', '-D', "$tempdir/tarbackup_l3", '-Ft' ],
+	'pg_basebackup tar with long symlink target');
+$node->safe_psql('postgres', "DROP TABLESPACE tblspc3;");
+rmtree("$tempdir/tarbackup_l3");
+
 $node->command_ok([ 'pg_basebackup', '-D', "$tempdir/backupR", '-R' ],
 	'pg_basebackup -R runs');
 ok(-f "$tempdir/backupR/postgresql.auto.conf", 'postgresql.auto.conf exists');
@@ -496,7 +510,7 @@ my $file_corrupt2 = $node->safe_psql('postgres',
 
 # set page header and block sizes
 my $pageheader_size = 24;
-my $block_size = $node->safe_psql('postgres', 'SHOW block_size;');
+my $block_size      = $node->safe_psql('postgres', 'SHOW block_size;');
 
 # induce corruption
 system_or_bail 'pg_ctl', '-D', $pgdata, 'stop';
diff --git a/src/bin/pg_dump/t/010_dump_connstr.pl b/src/bin/pg_dump/t/010_dump_connstr.pl
index abdb07c558..5497e46056 100644
--- a/src/bin/pg_dump/t/010_dump_connstr.pl
+++ b/src/bin/pg_dump/t/010_dump_connstr.pl
@@ -5,7 +5,7 @@ use PostgresNode;
 use TestLib;
 use Test::More;
 
-if ($^O eq 'msys' && `uname -or` =~ /^[2-9].*Msys/)
+if ($TestLib::is_msys2)
 {
 	plan skip_all => 'High bit name tests fail on Msys2';
 }
@@ -27,7 +27,7 @@ $ENV{PGCLIENTENCODING} = 'LATIN1';
 # The odds of finding something interesting by testing all ASCII letters
 # seem too small to justify the cycles of testing a fifth name.
 my $dbname1 =
-    'regression'
+	'regression'
   . generate_ascii_string(1,  9)
   . generate_ascii_string(11, 12)
   . generate_ascii_string(14, 33)
diff --git a/src/bin/pg_rewind/t/004_pg_xlog_symlink.pl b/src/bin/pg_rewind/t/004_pg_xlog_symlink.pl
index 3813543ee1..fff4758508 100644
--- a/src/bin/pg_rewind/t/004_pg_xlog_symlink.pl
+++ b/src/bin/pg_rewind/t/004_pg_xlog_symlink.pl
@@ -6,16 +6,7 @@ use warnings;
 use File::Copy;
 use File::Path qw(rmtree);
 use TestLib;
-use Test::More;
-if ($windows_os)
-{
-	plan skip_all => 'symlinks not supported on Windows';
-	exit;
-}
-else
-{
-	plan tests => 5;
-}
+use Test::More tests => 5;
 
 use FindBin;
 use lib $FindBin::RealBin;
@@ -36,7 +27,7 @@ sub run_test
 	# turn pg_wal into a symlink
 	print("moving $test_primary_datadir/pg_wal to $primary_xlogdir\n");
 	move("$test_primary_datadir/pg_wal", $primary_xlogdir) or die;
-	symlink($primary_xlogdir, "$test_primary_datadir/pg_wal") or die;
+	dir_symlink($primary_xlogdir, "$test_primary_datadir/pg_wal") or die;
 
 	RewindTest::start_primary();
 
diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pm
index a7490d2ce7..cbe87f8684 100644
--- a/src/test/perl/TestLib.pm
+++ b/src/test/perl/TestLib.pm
@@ -67,6 +67,7 @@ our @EXPORT = qw(
   check_mode_recursive
   chmod_recursive
   check_pg_config
+  dir_symlink
   system_or_bail
   system_log
   run_log
@@ -84,10 +85,12 @@ our @EXPORT = qw(
   command_checks_all
 
   $windows_os
+  $is_msys2
   $use_unix_sockets
 );
 
-our ($windows_os, $use_unix_sockets, $tmp_check, $log_path, $test_logfile);
+our ($windows_os, $is_msys2, $use_unix_sockets, $tmp_check, $log_path,
+	$test_logfile);
 
 BEGIN
 {
@@ -114,6 +117,9 @@ BEGIN
 
 	# Must be set early
 	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	# Check if this environment is MSYS2.
+	$is_msys2 = $^O eq 'msys' && `uname -or` =~ /^[2-9].*Msys/;
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -137,6 +143,10 @@ BEGIN
 
 Set to true when running under Windows, except on Cygwin.
 
+=item C<$is_msys2>
+
+Set to true when running under MSYS2.
+
 =back
 
 =cut
@@ -152,7 +162,7 @@ INIT
 	# TESTDIR environment variable, which is normally set by the invoking
 	# Makefile.
 	$tmp_check = $ENV{TESTDIR} ? "$ENV{TESTDIR}/tmp_check" : "tmp_check";
-	$log_path = "$tmp_check/log";
+	$log_path  = "$tmp_check/log";
 
 	mkdir $tmp_check;
 	mkdir $log_path;
@@ -263,9 +273,10 @@ sub tempdir_short
 
 =item perl2host()
 
-Translate a Perl file name to a host file name.  Currently, this is a no-op
+Translate a virtual file name to a host file name.  Currently, this is a no-op
 except for the case of Perl=msys and host=mingw32.  The subject need not
-exist, but its parent directory must exist.
+exist, but its parent or grandparent directory must exist unless cygpath is
+available.
 
 =cut
 
@@ -273,6 +284,17 @@ sub perl2host
 {
 	my ($subject) = @_;
 	return $subject unless $Config{osname} eq 'msys';
+	if ($is_msys2)
+	{
+		# get absolute, windows type path
+		my $path = qx{cygpath -a -w "$subject"};
+		if (!$?)
+		{
+			chomp $path;
+			return $path if $path;
+		}
+		# fall through if this didn't work.
+	}
 	my $here = cwd;
 	my $leaf;
 	if (chdir $subject)
@@ -283,7 +305,12 @@ sub perl2host
 	{
 		$leaf = '/' . basename $subject;
 		my $parent = dirname $subject;
-		chdir $parent or die "could not chdir \"$parent\": $!";
+		if (!chdir $parent)
+		{
+			$leaf   = '/' . basename($parent) . $leaf;
+			$parent = dirname $parent;
+			chdir $parent or die "could not chdir \"$parent\": $!";
+		}
 	}
 
 	# this odd way of calling 'pwd -W' is the only way that seems to work.
@@ -602,6 +629,40 @@ sub check_pg_config
 
 =pod
 
+=item dir_symlink(oldname, newname)
+
+Portably create a symlink for a directory. On Windows this creates a junction
+point. Elsewhere it just calls perl's builtin symlink.
+
+=cut
+
+sub dir_symlink
+{
+	my $oldname = shift;
+	my $newname = shift;
+	if ($windows_os)
+	{
+		$oldname = perl2host($oldname);
+		$newname = perl2host($newname);
+		$oldname =~ s,/,\\,g;
+		$newname =~ s,/,\\,g;
+		my $cmd = qq{mklink /j "$newname" "$oldname"};
+		if ($Config{osname} eq 'msys')
+		{
+			# need some indirection on msys
+			$cmd = qq{echo '$cmd' | \$COMSPEC /Q};
+		}
+		system($cmd);
+	}
+	else
+	{
+		symlink $oldname, $newname;
+	}
+	die "No $newname" unless -e $newname;
+}
+
+=pod
+
 =back
 
 =head1 Test::More-LIKE METHODS
@@ -664,7 +725,7 @@ sub command_exit_is
 	# long as the process was not terminated by an exception. To work around
 	# that, use $h->full_results on Windows instead.
 	my $result =
-	    ($Config{osname} eq "MSWin32")
+		($Config{osname} eq "MSWin32")
 	  ? ($h->full_results)[0]
 	  : $h->result(0);
 	is($result, $expected, $test_name);

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