manual merge bug#10952

mysql-test/r/merge.result:
  Auto merged
mysql-test/t/merge.test:
  Auto merged
sql/sql_table.cc:
  Auto merged

mysql-test/extra/binlog_tests/blackhole.test

@@ -147,3 +147,15 @@ set autocommit=1;
 --replace_column 2 # 5 #
 --replace_regex /table_id: [0-9]+/table_id: #/
 show binlog events;
+
+#
+# BUG#10952 - alter table ... lost data without errors and warnings
+#
+drop table if exists t1;
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+--error 1031
+alter table t1 engine=blackhole;
+drop table t1;
+
+# End of 5.0 tests

mysql-test/r/binlog_stm_blackhole.result

@@ -149,3 +149,11 @@ master-bin.000001	#	Query	1	#	use `test`; create table t1 (a int) engine=blackho
 master-bin.000001	#	Query	1	#	use `test`; BEGIN
 master-bin.000001	#	Query	1	#	use `test`; insert into t1 values(1)
 master-bin.000001	#	Query	1	#	use `test`; COMMIT
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+alter table t1 engine=blackhole;
+ERROR HY000: Table storage engine for 't1' doesn't have this option
+drop table t1;

mysql-test/r/merge.result

@@ -771,3 +771,11 @@ Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 test.t2	check	status	OK
 drop table t1, t2, t3;
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+alter table t1 engine=MERGE;
+ERROR HY000: Table storage engine for 't1' doesn't have this option
+drop table t1;

mysql-test/t/merge.test

@@ -382,3 +382,15 @@ check table t1, t2;
 drop table t1, t2, t3;
 
 # End of 4.1 tests
+
+#
+# BUG#10952 - alter table ... lost data without errors and warnings
+#
+drop table if exists t1;
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+--error 1031
+alter table t1 engine=MERGE;
+drop table t1;
+
+# End of 5.0 tests

sql/ha_myisammrg.cc

@@ -74,7 +74,7 @@ handlerton myisammrg_hton= {
   NULL,    /* Alter table flags */
   NULL,    /* Alter Tablespace */
   NULL,    /* Fill Files Table */
-  HTON_CAN_RECREATE,
+  HTON_CAN_RECREATE | HTON_ALTER_CANNOT_CREATE,
   NULL,    /* binlog_func */
   NULL,    /* binlog_log_query */
   NULL	   /* release_temporary_latches */

sql/handler.h

@@ -603,6 +603,7 @@ struct show_table_alias_st {
 #define HTON_FLUSH_AFTER_RENAME      (1 << 4)
 #define HTON_NOT_USER_SELECTABLE     (1 << 5)
 #define HTON_TEMPORARY_NOT_SUPPORTED (1 << 6) //Having temporary tables not supported
+#define HTON_ALTER_CANNOT_CREATE     (1 << 7) //Cannot use alter to create
 
 typedef struct st_thd_trans
 {

sql/sql_table.cc

@@ -5098,7 +5098,9 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
              ha_resolve_storage_engine_name(old_db_type),
              ha_resolve_storage_engine_name(new_db_type)));
   if (ha_check_storage_engine_flag(old_db_type, HTON_ALTER_NOT_SUPPORTED) ||
-      ha_check_storage_engine_flag(new_db_type, HTON_ALTER_NOT_SUPPORTED))
+      ha_check_storage_engine_flag(new_db_type, HTON_ALTER_NOT_SUPPORTED) ||
+      (old_db_type != new_db_type &&
+       ha_check_storage_engine_flag(new_db_type, HTON_ALTER_CANNOT_CREATE)))
   {
     DBUG_PRINT("info", ("doesn't support alter"));
     my_error(ER_ILLEGAL_HA, MYF(0), table_name);

storage/blackhole/ha_blackhole.cc

@@ -67,7 +67,7 @@ handlerton blackhole_hton= {
   NULL,    /* Alter table flags */
   NULL,    /* Alter Tablespace */
   NULL,    /* Fill FILES table */
-  HTON_CAN_RECREATE,
+  HTON_CAN_RECREATE | HTON_ALTER_CANNOT_CREATE,
   NULL,    /* binlog_func */
   NULL,    /* binlog_log_query */
   NULL	   /* release_temporary_latches */