Only ever test for non-127.0.0.1 addresses on Windows in PostgresNode

adunstan · adunstan · commit b93130450606 · 2021-04-21T10:25:31.000-04:00
This has been found to cause hangs where tcp usage is forced. Alexey Kodratov Discussion: https://postgr.es/m/82e271a9a11928337fcb5b5e57b423c0@postgrespro.ru Backpatch to all live branches
diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
@@ -1160,19 +1160,22 @@ sub get_free_port
 		# Check to see if anything else is listening on this TCP port.
 		# Seek a port available for all possible listen_addresses values,
 		# so callers can harness this port for the widest range of purposes.
-		# The 0.0.0.0 test achieves that for post-2006 Cygwin, which
-		# automatically sets SO_EXCLUSIVEADDRUSE.  The same holds for MSYS (a
-		# Cygwin fork).  Testing 0.0.0.0 is insufficient for Windows native
-		# Perl (https://stackoverflow.com/a/14388707), so we also test
-		# individual addresses.
+		# The 0.0.0.0 test achieves that for MSYS, which automatically sets
+		# SO_EXCLUSIVEADDRUSE.  Testing 0.0.0.0 is insufficient for Windows
+		# native Perl (https://stackoverflow.com/a/14388707), so we also
+		# have to test individual addresses.  Doing that for 127.0.0/24
+		# addresses other than 127.0.0.1 might fail with EADDRNOTAVAIL on
+		# non-Linux, non-Windows kernels.
 		#
-		# On non-Linux, non-Windows kernels, binding to 127.0.0/24 addresses
-		# other than 127.0.0.1 might fail with EADDRNOTAVAIL.  Binding to
-		# 0.0.0.0 is unnecessary on non-Windows systems.
+		# Thus, 0.0.0.0 and individual 127.0.0/24 addresses are tested
+		# only on Windows and only when TCP usage is requested.
 		if ($found == 1)
 		{
 			foreach my $addr (qw(127.0.0.1),
-				$use_tcp ? qw(127.0.0.2 127.0.0.3 0.0.0.0) : ())
+               $use_tcp ? qw(127.0.0.2 127.0.0.3 0.0.0.0) : ())
+               $use_tcp && $TestLib::windows_os
+               ? qw(127.0.0.2 127.0.0.3 0.0.0.0)
+               : ())
 			{
 				if (!can_bind($addr, $port))
 				{
