MDEV-16857 system-invisible row_end is displayed in SHOW INDEX

Skip system-invisible keypart in get_schema_stat_record().

mysql-test/suite/versioning/r/create.result

@@ -580,3 +580,22 @@ t2	CREATE TEMPORARY TABLE `t2` (
 ) ENGINE=DEFAULT_ENGINE DEFAULT CHARSET=latin1
 drop temporary table t2;
 drop table t1;
+#
+# MDEV-16857 system-invisible row_end is displayed in SHOW INDEX
+#
+create or replace table t1 (id int primary key, x int) with system versioning;
+select table_schema, table_name, non_unique, index_schema, index_name, seq_in_index, column_name
+from information_schema.statistics where table_name = 't1';
+table_schema	table_name	non_unique	index_schema	index_name	seq_in_index	column_name
+test	t1	0	test	PRIMARY	1	id
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
+t1	0	PRIMARY	1	id	#	#	#	#	#	#		
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `id` int(11) NOT NULL,
+  `x` int(11) DEFAULT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE=DEFAULT_ENGINE DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
+drop table t1;

mysql-test/suite/versioning/t/create.test

@@ -439,3 +439,15 @@ show create table t1;
 show create table t2;
 drop temporary table t2;
 drop table t1;
+
+--echo #
+--echo # MDEV-16857 system-invisible row_end is displayed in SHOW INDEX
+--echo #
+create or replace table t1 (id int primary key, x int) with system versioning;
+select table_schema, table_name, non_unique, index_schema, index_name, seq_in_index, column_name
+from information_schema.statistics where table_name = 't1';
+--replace_column 6 # 7 # 8 # 9 # 10 # 11 #
+show index from t1;
+--replace_result $default_engine DEFAULT_ENGINE
+show create table t1;
+drop table t1;

sql/sql_show.cc

@@ -6676,6 +6676,16 @@ static int get_schema_stat_record(THD *thd, TABLE_LIST *tables,
       LEX_CSTRING unknown= {STRING_WITH_LEN("?unknown field?") };
       for (uint j=0 ; j < key_info->user_defined_key_parts ; j++,key_part++)
       {
+        if (key_part->field->invisible >= INVISIBLE_SYSTEM &&
+            DBUG_EVALUATE_IF("test_completely_invisible", 0, 1))
+        {
+          /*
+            NOTE: we will get SEQ_IN_INDEX gap inside the result if this key_part
+            is not last (currently not possible). Though nothing is wrong with
+            that probably.
+          */
+          continue;
+        }
         restore_record(table, s->default_values);
         table->field[0]->store(STRING_WITH_LEN("def"), cs);
         table->field[1]->store(db_name->str, db_name->length, cs);