5.1 version of a fix and test cases for bugs:

Bug#4968 ""Stored procedure crash if cursor opened on altered table"
Bug#6895 "Prepared Statements: ALTER TABLE DROP COLUMN does nothing"
Bug#19182 "CREATE TABLE bar (m INT) SELECT n FROM foo; doesn't work from 
stored procedure."
Bug#19733 "Repeated alter, or repeated create/drop, fails"
Bug#22060 "ALTER TABLE x AUTO_INCREMENT=y in SP crashes server"
Bug#24879 "Prepared Statements: CREATE TABLE (UTF8 KEY) produces a 
growing key length" (this bug is not fixed in 5.0)

Re-execution of CREATE DATABASE, CREATE TABLE and ALTER TABLE 
statements in stored routines or as prepared statements caused
incorrect results (and crashes in versions prior to 5.0.25).

In 5.1 the problem occured only for CREATE DATABASE, CREATE TABLE
SELECT and CREATE TABLE with INDEX/DATA DIRECTOY options).
  
The problem of bugs 4968, 19733, 19282 and 6895 was that functions
mysql_prepare_table, mysql_create_table and mysql_alter_table are not
re-execution friendly: during their operation they modify contents
of LEX (members create_info, alter_info, key_list, create_list),
thus making the LEX unusable for the next execution.
In particular, these functions removed processed columns and keys from
create_list, key_list and drop_list. Search the code in sql_table.cc 
for drop_it.remove() and similar patterns to find evidence.
  
The fix is to supply to these functions a usable copy of each of the
above structures at every re-execution of an SQL statement. 
  
To simplify memory management, LEX::key_list and LEX::create_list
were added to LEX::alter_info, a fresh copy of which is created for
every execution.
  
The problem of crashing bug 22060 stemmed from the fact that the above 
metnioned functions were not only modifying HA_CREATE_INFO structure 
in LEX, but also were changing it to point to areas in volatile memory
of the execution memory root.
   
The patch solves this problem by creating and using an on-stack
copy of HA_CREATE_INFO in mysql_execute_command.

Additionally, this patch splits the part of mysql_alter_table
that analizes and rewrites information from the parser into
a separate function - mysql_prepare_alter_table, in analogy with
mysql_prepare_table, which is renamed to mysql_prepare_create_table.

1 files changed, 168 insertions, 0 deletions

diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result
index b811a27203c..0216ec2a174 100644
--- a/mysql-test/r/ps.result
+++ b/mysql-test/r/ps.result
@@ -1062,6 +1062,87 @@ EXECUTE stmt USING @a;
 0	0
 DEALLOCATE PREPARE stmt;
 DROP TABLE t1;
+DROP TABLE IF EXISTS t1, t2;
+CREATE TABLE t1 (i INT);
+PREPARE st_19182
+FROM "CREATE TABLE t2 (i INT, j INT, KEY (i), KEY(j)) SELECT i FROM t1";
+EXECUTE st_19182;
+DESC t2;
+Field	Type	Null	Key	Default	Extra
+j	int(11)	YES	MUL	NULL	
+i	int(11)	YES	MUL	NULL	
+DROP TABLE t2;
+EXECUTE st_19182;
+DESC t2;
+Field	Type	Null	Key	Default	Extra
+j	int(11)	YES	MUL	NULL	
+i	int(11)	YES	MUL	NULL	
+DEALLOCATE PREPARE st_19182;
+DROP TABLE t2, t1;
+drop database if exists mysqltest;
+drop table if exists t1, t2;
+create database mysqltest character set utf8;
+prepare stmt1 from "create table mysqltest.t1 (c char(10))";
+prepare stmt2 from "create table mysqltest.t2 select 'test'";
+execute stmt1;
+execute stmt2;
+show create table mysqltest.t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c` char(10) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=utf8
+show create table mysqltest.t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `test` varchar(4) CHARACTER SET latin1 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=utf8
+drop table mysqltest.t1;
+drop table mysqltest.t2;
+alter database mysqltest character set latin1;
+execute stmt1;
+execute stmt2;
+show create table mysqltest.t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c` char(10) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+show create table mysqltest.t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `test` varchar(4) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop database mysqltest;
+deallocate prepare stmt1;
+deallocate prepare stmt2;
+execute stmt;
+show create table t1;
+drop table t1;
+execute stmt;
+show create table t1;
+drop table t1;
+deallocate prepare stmt;
+CREATE TABLE t1(a int);
+INSERT INTO t1 VALUES (2), (3), (1);
+PREPARE st1 FROM
+'(SELECT a FROM t1) UNION (SELECT a+10 FROM t1) ORDER BY RAND()*0+a';
+EXECUTE st1;
+a
+1
+2
+3
+11
+12
+13
+EXECUTE st1;
+a
+1
+2
+3
+11
+12
+13
+DEALLOCATE PREPARE st1;
+DROP TABLE t1;
 End of 4.1 tests.
 create table t1 (a varchar(20));
 insert into t1 values ('foo');
@@ -1544,6 +1625,72 @@ a
 2
 DEALLOCATE PREPARE stmt;
 DROP TABLE t1,t2;
+drop table if exists t1;
+create table t1 (s1 char(20));
+prepare stmt from "alter table t1 modify s1 int";
+execute stmt;
+execute stmt;
+drop table t1;
+deallocate prepare stmt;
+drop table if exists t1;
+create table t1 (a int, b int);
+prepare s_6895 from "alter table t1 drop column b";
+execute s_6895;
+show columns from t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	YES		NULL	
+drop table t1;
+create table t1 (a int, b int);
+execute s_6895;
+show columns from t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	YES		NULL	
+drop table t1;
+create table t1 (a int, b int);
+execute s_6895;
+show columns from t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	YES		NULL	
+deallocate prepare s_6895;
+drop table t1;
+create table t1 (i int primary key auto_increment) comment='comment for table t1';
+create table t2 (i int, j int, k int);
+prepare stmt from "alter table t1 auto_increment=100";
+execute stmt;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `i` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`i`)
+) ENGINE=MyISAM AUTO_INCREMENT=100 DEFAULT CHARSET=latin1 COMMENT='comment for table t1'
+flush tables;
+select * from t2;
+i	j	k
+execute stmt;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `i` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`i`)
+) ENGINE=MyISAM AUTO_INCREMENT=100 DEFAULT CHARSET=latin1 COMMENT='comment for table t1'
+deallocate prepare stmt;
+drop table t1, t2;
+set @old_character_set_server= @@character_set_server;
+set @@character_set_server= latin1;
+prepare stmt from "create database mysqltest_1";
+execute stmt;
+show create database mysqltest_1;
+Database	Create Database
+mysqltest_1	CREATE DATABASE `mysqltest_1` /*!40100 DEFAULT CHARACTER SET latin1 */
+drop database mysqltest_1;
+set @@character_set_server= utf8;
+execute stmt;
+show create database mysqltest_1;
+Database	Create Database
+mysqltest_1	CREATE DATABASE `mysqltest_1` /*!40100 DEFAULT CHARACTER SET utf8 */
+drop database mysqltest_1;
+deallocate prepare stmt;
+set @@character_set_server= @old_character_set_server;
 drop tables if exists t1;
 create table t1 (id int primary key auto_increment, value varchar(10));
 insert into t1 (id, value) values (1, 'FIRST'), (2, 'SECOND'), (3, 'THIRD');
@@ -2524,4 +2671,25 @@ i	j
 4	5
 3	NULL
 DROP TABLE t1, t2;
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+prepare stmt
+from "create table t1 (c char(100) character set utf8, key (c(10)))";
+execute stmt;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c` char(100) CHARACTER SET utf8 DEFAULT NULL,
+  KEY `c` (`c`(10))
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
+execute stmt;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c` char(100) CHARACTER SET utf8 DEFAULT NULL,
+  KEY `c` (`c`(10))
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
 End of 5.1 tests.