merge

mysql-test/r/partition_mgm.result

 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)

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

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)

sql/sql_partition.cc

@@ -4233,9 +4233,8 @@ 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)
       {