manual merge

mysql-test/r/information_schema.result

@@ -1470,6 +1470,10 @@ f7	datetime	NO		NULL
 f8	datetime	YES		2006-01-01 00:00:00	
 drop table t1;
 End of 5.0 tests.
+show fields from information_schema.TABLE_NAMES;
+ERROR 42S02: Unknown table 'TABLE_NAMES' in information_schema
+show keys from information_schema.TABLE_NAMES;
+ERROR 42S02: Unknown table 'TABLE_NAMES' in information_schema
 select * from information_schema.engines WHERE ENGINE="MyISAM";
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 MyISAM	DEFAULT	Default engine as of MySQL 3.23 with great performance	NO	NO	NO

mysql-test/t/information_schema.test

@@ -1090,6 +1090,15 @@ show columns from t1;
 drop table t1;
 
 --echo End of 5.0 tests.
+
+#
+# Bug#30079 A check for "hidden" I_S tables is flawed
+#
+--error 1109
+show fields from information_schema.TABLE_NAMES;
+--error 1109
+show keys from information_schema.TABLE_NAMES;
+
 #
 # Show engines
 #

sql/sql_parse.cc

@@ -5766,7 +5766,12 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
     ST_SCHEMA_TABLE *schema_table= find_schema_table(thd, ptr->table_name);
     if (!schema_table ||
         (schema_table->hidden && 
-         (sql_command_flags[lex->sql_command] & CF_STATUS_COMMAND) == 0))
+         ((sql_command_flags[lex->sql_command] & CF_STATUS_COMMAND) == 0 || 
+          /*
+            this check is used for show columns|keys from I_S hidden table
+          */
+          lex->orig_sql_command == SQLCOM_SHOW_FIELDS ||
+          lex->orig_sql_command == SQLCOM_SHOW_KEYS)))
     {
       my_error(ER_UNKNOWN_TABLE, MYF(0),
                ptr->table_name, INFORMATION_SCHEMA_NAME.str);