From 8f39d2584ba0ba33998461aa93a714f8cadf498d Mon Sep 17 00:00:00 2001
From: Mattias Jonsson <mattias.jonsson@sun.com>
Date: Tue, 2 Dec 2008 11:18:01 +0100
Subject: [PATCH] Bug#40389: REORGANIZE PARTITION crashes when only using one
 partition

The non documented command 'ALTER PARTITION t REORGANIZE PARTITION'
(without any partitions!) which only make sense for nativly
partitioned engines, such as NDB, crashes the server if there was
no change of number of partitions.

The problem was wrong usage of fast_end_partition function,
which led to usage of a non initialized variable.
---
 mysql-test/r/partition_mgm.result |  7 +++++++
 mysql-test/t/partition_mgm.test   | 11 +++++++++++
 sql/partition_info.cc             |  1 +
 sql/sql_partition.cc              |  5 ++---
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/mysql-test/r/partition_mgm.result b/mysql-test/r/partition_mgm.result
index 9ef220028b3..eeb9be949a0 100644
--- a/mysql-test/r/partition_mgm.result
+++ b/mysql-test/r/partition_mgm.result
@@ -1,4 +1,11 @@
 DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a INT PRIMARY KEY)
+ENGINE MYISAM
+PARTITION BY HASH (a)
+PARTITIONS 1;
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+ALTER TABLE t1 REORGANIZE PARTITION;
+DROP TABLE t1;
 create table t1 (a int)
 partition by range (a)
 subpartition by key (a)
diff --git a/mysql-test/t/partition_mgm.test b/mysql-test/t/partition_mgm.test
index 68da4a5b390..1f53989b4d4 100644
--- a/mysql-test/t/partition_mgm.test
+++ b/mysql-test/t/partition_mgm.test
@@ -3,6 +3,17 @@
 DROP TABLE IF EXISTS t1;
 --enable_warnings
 
+#
+# Bug 40389: REORGANIZE PARTITION crashes when only using one partition
+#
+CREATE TABLE t1 (a INT PRIMARY KEY)
+ENGINE MYISAM
+PARTITION BY HASH (a)
+PARTITIONS 1;
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+ALTER TABLE t1 REORGANIZE PARTITION;
+DROP TABLE t1;
+
 #
 # Bug 21143: mysqld hang when error in number of subparts in
 #            REORGANIZE command
diff --git a/sql/partition_info.cc b/sql/partition_info.cc
index 02f2c9b0ab1..e2027d3571e 100644
--- a/sql/partition_info.cc
+++ b/sql/partition_info.cc
@@ -867,6 +867,7 @@ bool partition_info::check_partition_info(THD *thd, handlerton **eng_type,
 
     if (part_type != HASH_PARTITION || !list_of_part_fields)
     {
+      DBUG_ASSERT(part_expr);
       err= part_expr->walk(&Item::check_partition_func_processor, 0,
                            NULL);
       if (!err && is_sub_partitioned() && !list_of_subpart_fields)
diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index da80a2125e9..6fb803ce4ff 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -4228,9 +4228,8 @@ uint prep_alter_part_table(THD *thd, TABLE *table, Alter_info *alter_info,
           after the change as before. Thus we can reply ok immediately
           without any changes at all.
         */
-        DBUG_RETURN(fast_end_partition(thd, ULL(0), ULL(0),
-                                       table, NULL,
-                                       TRUE, NULL, FALSE));
+        *fast_alter_partition= TRUE;
+        DBUG_RETURN(FALSE);
       }
       else if (new_part_no > curr_part_no)
       {