From b7560c3387fa7110773cfdb6ddfa6fd62ae909fc Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 14 Nov 2023 16:08:28 +0900
Subject: [PATCH v3 2/3] Add regression test to show snapbuild consistency

Reverted 409f9ca44713 causes the test to fail.
---
 src/backend/replication/logical/snapbuild.c   |  3 ++
 .../modules/test_injection_points/Makefile    |  2 +
 .../t/001_snapshot_status.pl                  | 47 +++++++++++++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 src/test/modules/test_injection_points/t/001_snapshot_status.pl

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index fec190a8b2..a65ed3d5bb 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -141,6 +141,7 @@
 #include "storage/procarray.h"
 #include "storage/standby.h"
 #include "utils/builtins.h"
+#include "utils/injection_point.h"
 #include "utils/memutils.h"
 #include "utils/snapmgr.h"
 #include "utils/snapshot.h"
@@ -654,6 +655,8 @@ SnapBuildInitialSnapshot(SnapBuild *builder)
 	snap->xcnt = newxcnt;
 	snap->xip = newxip;
 
+	INJECTION_POINT_RUN("SnapBuildInitialSnapshot");
+
 	return snap;
 }
 
diff --git a/src/test/modules/test_injection_points/Makefile b/src/test/modules/test_injection_points/Makefile
index 65bcdde782..4696c1b013 100644
--- a/src/test/modules/test_injection_points/Makefile
+++ b/src/test/modules/test_injection_points/Makefile
@@ -10,6 +10,8 @@ EXTENSION = test_injection_points
 DATA = test_injection_points--1.0.sql
 REGRESS = test_injection_points
 
+TAP_TESTS = 1
+
 ifdef USE_PGXS
 PG_CONFIG = pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
diff --git a/src/test/modules/test_injection_points/t/001_snapshot_status.pl b/src/test/modules/test_injection_points/t/001_snapshot_status.pl
new file mode 100644
index 0000000000..e4670fb4d9
--- /dev/null
+++ b/src/test/modules/test_injection_points/t/001_snapshot_status.pl
@@ -0,0 +1,47 @@
+# Test consistent of initial snapshot data.
+
+# This requires a node with wal_level=logical combined with an injection
+# point that forces a failure when a snapshot is initially built with a
+# logical slot created.
+#
+# See bug https://postgr.es/m/CAFiTN-s0zA1Kj0ozGHwkYkHwa5U0zUE94RSc_g81WrpcETB5=w@mail.gmail.com.
+
+use strict;
+use warnings;
+
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+my $node = PostgreSQL::Test::Cluster->new('node');
+$node->init(allows_streaming => 'logical');
+$node->start;
+
+$node->safe_psql('postgres', 'CREATE EXTENSION test_injection_points;');
+$node->safe_psql('postgres',
+  "SELECT test_injection_points_create('SnapBuildInitialSnapshot', 'error');");
+
+my $node_host = $node->host;
+my $node_port = $node->port;
+my $connstr_common = "host=$node_host port=$node_port";
+my $connstr_db = "$connstr_common replication=database dbname=postgres";
+
+# This requires a single session, with two commands.
+my $psql_session =
+  $node->background_psql('postgres', on_error_stop => 0,
+			 extra_params => [ '-d', $connstr_db ]);
+my ($output, $ret) = $psql_session->query(
+    'CREATE_REPLICATION_SLOT "slot" LOGICAL "pgoutput";');
+ok($ret != 0, "First CREATE_REPLICATION_SLOT fails on injected error");
+
+# Now remove the injected error and check that the second command works.
+$node->safe_psql('postgres',
+  "SELECT test_injection_points_drop('SnapBuildInitialSnapshot');");
+
+($output, $ret) = $psql_session->query(
+    'CREATE_REPLICATION_SLOT "slot" LOGICAL "pgoutput";');
+print "BOO" . substr($output, 0, 4) . "\n";
+ok(substr($output, 0, 4) eq 'slot',
+   "Second CREATE_REPLICATION_SLOT passes");
+
+done_testing();
-- 
2.42.0