bug #15521 (Cannot reorganise a partition with a new name equal to the old name)

mysql-test/r/partition.result:
  result fixed
mysql-test/r/partition_mgm_err.result:
  result fixed
mysql-test/t/partition.test:
  test case added
mysql-test/t/partition_mgm_err.test:
  test modified to produce the declared error
sql/handler.h:
  check_reorganise_list interface
sql/sql_partition.cc:
  check_reorganise_list implementation
sql/sql_table.cc:
  now we call check_reorganise_list to do proper test.
  Also we should set right no_parts value as it can change here

mysql-test/r/partition.result

@@ -114,3 +114,37 @@ CREATE TABLE `t1` (
 SELECT * FROM t1;
 id
 drop table t1;
+create table t1
+(a int)
+partition by range (a)
+( partition p0 values less than(10),
+partition p1 values less than (20),
+partition p2 values less than maxvalue);
+alter table t1 reorganise partition p2 into (partition p2 values less than (30));
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) default NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY RANGE (a) (PARTITION p0 VALUES LESS THAN (10) ENGINE = MyISAM, PARTITION p1 VALUES LESS THAN (20) ENGINE = MyISAM, PARTITION p2 VALUES LESS THAN (30) ENGINE = MyISAM)
+drop table t1;
+CREATE TABLE t1 (a int, b int)
+PARTITION BY RANGE (a)
+(PARTITION x0 VALUES LESS THAN (2),
+PARTITION x1 VALUES LESS THAN (4),
+PARTITION x2 VALUES LESS THAN (6),
+PARTITION x3 VALUES LESS THAN (8),
+PARTITION x4 VALUES LESS THAN (10),
+PARTITION x5 VALUES LESS THAN (12),
+PARTITION x6 VALUES LESS THAN (14),
+PARTITION x7 VALUES LESS THAN (16),
+PARTITION x8 VALUES LESS THAN (18),
+PARTITION x9 VALUES LESS THAN (20));
+ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2 INTO
+(PARTITION x1 VALUES LESS THAN (6));
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) default NULL,
+  `b` int(11) default NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY RANGE (a) (PARTITION x1 VALUES LESS THAN (6) ENGINE = MyISAM, PARTITION x3 VALUES LESS THAN (8) ENGINE = MyISAM, PARTITION x4 VALUES LESS THAN (10) ENGINE = MyISAM, PARTITION x5 VALUES LESS THAN (12) ENGINE = MyISAM, PARTITION x6 VALUES LESS THAN (14) ENGINE = MyISAM, PARTITION x7 VALUES LESS THAN (16) ENGINE = MyISAM, PARTITION x8 VALUES LESS THAN (18) ENGINE = MyISAM, PARTITION x9 VALUES LESS THAN (20) ENGINE = MyISAM)
+drop table t1;

mysql-test/r/partition_mgm_err.result

@@ -26,7 +26,7 @@ ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,x10 INTO
 (PARTITION x11 VALUES LESS THAN (22));
 ERROR HY000: More partitions to reorganise than there are partitions
 ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2 INTO
-(PARTITION x1 VALUES LESS THAN (6));
+(PARTITION x3 VALUES LESS THAN (6));
 ERROR HY000: All partitions must have unique names in the table
 ALTER TABLE t1 REORGANISE PARTITION x0, x2 INTO
 (PARTITION x11 VALUES LESS THAN (2));

mysql-test/t/partition.test

@@ -172,3 +172,34 @@ SELECT * FROM t1;
 
 drop table t1;
 
+#
+# BUG 15221 (Cannot reorganize with the same name)
+#
+create table t1
+(a int)
+partition by range (a)
+  ( partition p0 values less than(10),
+    partition p1 values less than (20),
+    partition p2 values less than maxvalue);
+
+alter table t1 reorganise partition p2 into (partition p2 values less than (30));
+show create table t1;
+drop table t1;
+
+CREATE TABLE t1 (a int, b int)
+PARTITION BY RANGE (a)
+(PARTITION x0 VALUES LESS THAN (2),
+ PARTITION x1 VALUES LESS THAN (4),
+ PARTITION x2 VALUES LESS THAN (6),
+ PARTITION x3 VALUES LESS THAN (8),
+ PARTITION x4 VALUES LESS THAN (10),
+ PARTITION x5 VALUES LESS THAN (12),
+ PARTITION x6 VALUES LESS THAN (14),
+ PARTITION x7 VALUES LESS THAN (16),
+ PARTITION x8 VALUES LESS THAN (18),
+ PARTITION x9 VALUES LESS THAN (20));
+
+ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2 INTO
+(PARTITION x1 VALUES LESS THAN (6));
+show create table t1;
+drop table t1;

mysql-test/t/partition_mgm_err.test

@@ -43,7 +43,7 @@ ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,x10 INTO
 
 --error ER_SAME_NAME_PARTITION
 ALTER TABLE t1 REORGANISE PARTITION x0,x1,x2 INTO
-(PARTITION x1 VALUES LESS THAN (6));
+(PARTITION x3 VALUES LESS THAN (6));
 
 --error ER_CONSECUTIVE_REORG_PARTITIONS
 ALTER TABLE t1 REORGANISE PARTITION x0, x2 INTO

sql/handler.h

@@ -717,6 +717,9 @@ typedef struct st_ha_check_opt
 bool is_partition_in_list(char *part_name, List<char> list_part_names);
 bool is_partitions_in_table(partition_info *new_part_info,
                             partition_info *old_part_info);
+bool check_reorganise_list(partition_info *new_part_info,
+                           partition_info *old_part_info,
+                           List<char> list_part_names);
 bool set_up_defaults_for_partitioning(partition_info *part_info,
                                       handler *file,
                                       ulonglong max_rows,

sql/sql_partition.cc

@@ -189,6 +189,61 @@ bool is_partitions_in_table(partition_info *new_part_info,
 }
 
 
+/*
+  Check that the reorganized table will not have duplicate partitions.
+
+  SYNOPSIS
+    check_reorganise_list()
+    new_part_info      New partition info
+    old_part_info      Old partition info
+    list_part_names    The list of partition names that will go away and can be reused in the
+                       new table.
+
+  RETURN VALUES
+    TRUE               Inacceptable name conflict detected.
+    FALSE              New names are OK.
+
+  DESCRIPTION
+    Can handle that the 'new_part_info' and 'old_part_info' the same
+    in which case it checks that the list of names in the partitions
+    doesn't contain any duplicated names.
+*/
+
+bool check_reorganise_list(partition_info *new_part_info,
+                           partition_info *old_part_info,
+                           List<char> list_part_names)
+{
+  uint new_count, old_count;
+  uint no_new_parts= new_part_info->partitions.elements;
+  uint no_old_parts= old_part_info->partitions.elements;
+  List_iterator<partition_element> new_parts_it(new_part_info->partitions);
+  bool same_part_info= (new_part_info == old_part_info);
+  DBUG_ENTER("check_reorganise_list");
+
+  new_count= 0;
+  do
+  {
+    List_iterator<partition_element> old_parts_it(old_part_info->partitions);
+    char *new_name= (new_parts_it++)->partition_name;
+    new_count++;
+    old_count= 0;
+    do
+    {
+      char *old_name= (old_parts_it++)->partition_name;
+      old_count++;
+      if (same_part_info && old_count == new_count)
+        break;
+      if (!(my_strcasecmp(system_charset_info, old_name, new_name)))
+      {
+        if (!is_partition_in_list(old_name, list_part_names))
+          DBUG_RETURN(TRUE);
+      }
+    } while (old_count < no_old_parts);
+  } while (new_count < no_new_parts);
+  DBUG_RETURN(FALSE);
+}
+
+
 /*
   A useful routine used by update_row for partition handlers to calculate
   the partition ids of the old and the new record.

sql/sql_table.cc

@@ -3832,7 +3832,8 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
         my_error(ER_ONLY_ON_RANGE_LIST_PARTITION, MYF(0), "REORGANISE");
         DBUG_RETURN(TRUE);
       }
-      if (is_partitions_in_table(alt_part_info, tab_part_info))
+      if (check_reorganise_list(alt_part_info, tab_part_info,
+                                alter_info->partition_names))
       {
         my_error(ER_SAME_NAME_PARTITION, MYF(0));
         DBUG_RETURN(TRUE);
@@ -3901,6 +3902,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
       }
     }
     partition_changed= TRUE;
+    tab_part_info->no_parts= tab_part_info->partitions.elements;
     create_info->db_type= DB_TYPE_PARTITION_DB;
     thd->lex->part_info= tab_part_info;
     if (alter_info->flags == ALTER_ADD_PARTITION ||