MDEV-22881 Unexpected errors, corrupt output, Valgrind / ASAN errors in...

MDEV-22881 Unexpected errors, corrupt output, Valgrind / ASAN errors in Item_ident::print or append_identifier

After this code

end_inplace:

  if (thd->locked_tables_list.reopen_tables(thd, false))
    goto err_with_mdl_after_alter;

table is not reopened (need_reopen is false) but
some_table_marked_for_reopen is reset to false.

Item_field is allocated on table lock and assigned new name on first
ALTER which is then freed at the end of the command. Second ALTER
accessess this Item_field and gets garbage value.

mysql-test/main/alter_table.result

@@ -3311,5 +3311,16 @@ t2	CREATE TABLE `t2` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t2;
 #
+# MDEV-22881 Unexpected errors, corrupt output, Valgrind / ASAN errors in Item_ident::print or append_identifier
+#
+create table t1 (a int check (a >= 0));
+lock tables t1 write;
+alter table t1 rename column a to a;
+alter table t1 rename key if exists x to xx;
+Warnings:
+Note	1176	Key 'x' doesn't exist in table 't1'
+unlock tables;
+drop table t1;
+#
 # End of 10.5 tests
 #

mysql-test/main/alter_table.test

@@ -2517,6 +2517,18 @@ alter table if exists t1 rename t2;
 show create table t2;
 drop table t2;
 
+--echo #
+--echo # MDEV-22881 Unexpected errors, corrupt output, Valgrind / ASAN errors in Item_ident::print or append_identifier
+--echo #
+create table t1 (a int check (a >= 0));
+lock tables t1 write;
+alter table t1 rename column a to a;
+alter table t1 rename key if exists x to xx;
+
+# cleanup
+unlock tables;
+drop table t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

sql/sql_base.cc

@@ -2592,7 +2592,8 @@ Locked_tables_list::reopen_tables(THD *thd, bool need_reopen)
 
 
   /* Reset flag that some table was marked for reopen */
-  some_table_marked_for_reopen= 0;
+  if (need_reopen)
+    some_table_marked_for_reopen= 0;
 
   for (TABLE_LIST *table_list= m_locked_tables;
        table_list; table_list= table_list->next_global)