[CF 5741] v1 - Fix hostaddr crash during non-blocking cancellation

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5741

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/CAOYmi+mQCHUm5uQ3ThBv0g42wyNt4OSAmM8r2V7YwuAf5bm5vA@mail.gmail.com
Author(s): Jacob Champion

Author: Commitfest Bot

.cirrus.tasks.yml

@@ -29,7 +29,7 @@ env:
   MTEST_ARGS: --print-errorlogs --no-rebuild -C build
   PGCTLTIMEOUT: 120 # avoids spurious failures during parallel tests
   TEMP_CONFIG: ${CIRRUS_WORKING_DIR}/src/tools/ci/pg_ci_base.conf
-  PG_TEST_EXTRA: kerberos ldap ssl libpq_encryption load_balance oauth
+  PG_TEST_EXTRA: kerberos ldap ssl libpq_encryption load_balance oauth tcp
 
 
 # What files to preserve in case tests fail

src/interfaces/libpq/fe-cancel.c

@@ -137,6 +137,8 @@ PQcancelCreate(PGconn *conn)
 		goto oom_error;
 
 	originalHost = conn->connhost[conn->whichhost];
+	cancelConn->connhost[0].type = originalHost.type;
+
 	if (originalHost.host)
 	{
 		cancelConn->connhost[0].host = strdup(originalHost.host);

src/test/modules/libpq_pipeline/meson.build

@@ -26,6 +26,7 @@ tests += {
   'tap': {
     'tests': [
       't/001_libpq_pipeline.pl',
+      't/002_tcp.pl',
     ],
     'deps': [libpq_pipeline],
   },

src/test/modules/libpq_pipeline/t/002_tcp.pl

@@ -0,0 +1,45 @@
+
+# Copyright (c) 2021-2025, PostgreSQL Global Development Group
+
+use strict;
+use warnings FATAL => 'all';
+
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Force test nodes to begin in TCP mode.
+# Use an INIT block so it runs after the BEGIN block in Utils.pm.
+
+INIT { $PostgreSQL::Test::Utils::use_unix_sockets = 0; }
+
+use PostgreSQL::Test::Cluster;
+
+if (!$ENV{PG_TEST_EXTRA} || $ENV{PG_TEST_EXTRA} !~ /\btcp\b/)
+{
+	plan skip_all =>
+	  'Potentially unsafe test TCP not enabled in PG_TEST_EXTRA';
+}
+
+my $node = PostgreSQL::Test::Cluster->new('main');
+$node->init;
+$node->start;
+
+# Don't let PGHOST interfere with these tests.
+delete $ENV{PGHOST};
+
+my @cases = (
+	$node->connstr('postgres') . " max_protocol_version=latest",
+	$node->connstr('postgres') . " max_protocol_version=3.0",
+	"hostaddr=127.0.0.1 port=" . $node->port);
+
+foreach my $c (@cases)
+{
+	# Don't use $node->command_ok(); it overrides PGHOST too.
+	command_ok(
+		[ 'libpq_pipeline', 'cancel', $c ],
+		"libpq_pipeline cancel, connstr: " . $c);
+}
+
+$node->stop('fast');
+
+done_testing();