From 040a1df6149f852c3b8de96d9d13258af8a39e23 Mon Sep 17 00:00:00 2001
From: Andrew Dunstan <andrew@dunslane.net>
Date: Wed, 24 Oct 2018 10:45:34 -0400
Subject: [PATCH] Correctly set t_self for heap tuples in expand_tuple

Commit 16828d5c0 incorrectly set an invalid pointer for t_self for heap
tuples. This patch correctly copies it from the source tuple, and
includes a regression test that relies on it being set correctly.

Backpatch to release 11.

Fixes bug #15448 reported by Tillmann Schulz

Diagnosis and test case by Amit Langote
---
 src/backend/access/common/heaptuple.c      |  2 +-
 src/test/regress/expected/fast_default.out | 10 ++++++++++
 src/test/regress/sql/fast_default.sql      | 12 ++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index 15444cf582..28127b311f 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -856,7 +856,7 @@ expand_tuple(HeapTuple *targetHeapTuple,
 			= (HeapTupleHeader) ((char *) *targetHeapTuple + HEAPTUPLESIZE);
 		(*targetHeapTuple)->t_len = len;
 		(*targetHeapTuple)->t_tableOid = sourceTuple->t_tableOid;
-		ItemPointerSetInvalid(&((*targetHeapTuple)->t_self));
+		(*targetHeapTuple)->t_self = sourceTuple->t_self;
 
 		targetTHeader->t_infomask = sourceTHeader->t_infomask;
 		targetTHeader->t_hoff = hoff;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 48bd360a79..0797e11128 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -727,7 +727,17 @@ SELECT * FROM t;
 (1 row)
 
 DROP TABLE t;
+-- make sure expanded tuple has correct self pointer
+-- it will be required by the RI tigger doing the cascading delete
+CREATE TABLE leader (a int PRIMARY KEY, b int);
+CREATE TABLE follower (a int REFERENCES leader ON DELETE CASCADE, b int);
+INSERT INTO leader VALUES (1, 1), (2, 2);
+ALTER TABLE leader ADD c int;
+ALTER TABLE leader DROP c;
+DELETE FROM leader;
 -- cleanup
+DROP TABLE follower;
+DROP TABLE leader;
 DROP FUNCTION test_trigger();
 DROP TABLE t1;
 DROP FUNCTION set(name);
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index 06205cb39f..eefcd497e5 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -471,7 +471,19 @@ UPDATE t SET y = 2;
 SELECT * FROM t;
 DROP TABLE t;
 
+-- make sure expanded tuple has correct self pointer
+-- it will be required by the RI tigger doing the cascading delete
+
+CREATE TABLE leader (a int PRIMARY KEY, b int);
+CREATE TABLE follower (a int REFERENCES leader ON DELETE CASCADE, b int);
+INSERT INTO leader VALUES (1, 1), (2, 2);
+ALTER TABLE leader ADD c int;
+ALTER TABLE leader DROP c;
+DELETE FROM leader;
+
 -- cleanup
+DROP TABLE follower;
+DROP TABLE leader;
 DROP FUNCTION test_trigger();
 DROP TABLE t1;
 DROP FUNCTION set(name);