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

adunstan · adunstan · commit 1d997cb37532 · 2021-04-21T10:30:26.000-04:00
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
@@ -977,28 +977,25 @@ sub get_new_node
 			$found = 0 if ($node->port == $port);
 		}
 
-		# Check to see if anything else is listening on this TCP port.  This
-		# is *necessary* on $use_tcp (Windows) configurations.  Seek a port
-		# available for all possible listen_addresses values, for own_host
-		# nodes and so the caller can harness this port for the widest range
-		# of purposes.  The 0.0.0.0 test achieves that for post-2006 Cygwin,
-		# which automatically sets SO_EXCLUSIVEADDRUSE.  The same holds for
-		# MSYS (a Cygwin fork).  Testing 0.0.0.0 is insufficient for Windows
-		# native Perl (https://stackoverflow.com/a/14388707), so we also test
-		# individual addresses.
+		# Check to see if anything else is listening on this TCP port.
+		# Seek a port available for all possible listen_addresses values,
+		# so callers can harness this port for the widest range of purposes.
+		# The 0.0.0.0 test achieves that for MSYS, which automatically sets
+		# SO_EXCLUSIVEADDRUSE.  Testing 0.0.0.0 is insufficient for Windows
+		# native Perl (https://stackoverflow.com/a/14388707), so we also
+		# have to test individual addresses.  Doing that for 127.0.0/24
+		# addresses other than 127.0.0.1 might fail with EADDRNOTAVAIL on
+		# non-Linux, non-Windows kernels.
 		#
-		# This seems like a good idea on Unixen as well, even though we don't
-		# ask the postmaster to open a TCP port on Unix.  On Non-Linux,
-		# non-Windows kernels, binding to 127.0.0.1/24 addresses other than
-		# 127.0.0.1 might fail with EADDRNOTAVAIL.  Binding to 0.0.0.0 is
-		# unnecessary on non-Windows systems.
-		#
-		# XXX A port available now may become unavailable by the time we start
-		# the postmaster.
+		# Thus, 0.0.0.0 and individual 127.0.0/24 addresses are tested
+		# only on Windows and only when TCP usage is requested.
 		if ($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 && $TestLib::windows_os
+               ? qw(127.0.0.2 127.0.0.3 0.0.0.0)
+               : ())
 			{
 				can_bind($addr, $port) or $found = 0;
 			}
