MDEV-31164 default current_timestamp() not working when used INSERT ON DUPLICATE KEY in some cases

select_insert::store_values() must reset
has_value_set bitmap before every row, just like mysql_insert() does.
because ON DUPLICATE KEY UPDATE and triggers modify it

mysql-test/main/insert_update.result

@@ -412,3 +412,44 @@ select if( @stamp1 = @stamp2, "correct", "wrong");
 if( @stamp1 = @stamp2, "correct", "wrong")
 correct
 drop table t1;
+#
+# MDEV-31164 default current_timestamp() not working when used INSERT ON DUPLICATE KEY in some cases
+#
+set timestamp=unix_timestamp('2000-10-20 0:0:0');
+create table t1 (pk integer primary key, val varchar(20) not null, ts timestamp);
+insert t1 (pk, val) values(1, 'val1');
+select * from t1;
+pk	val	ts
+1	val1	2000-10-20 00:00:00
+set timestamp=unix_timestamp('2000-10-20 1:0:0');
+insert t1 (pk, val) select 2, 'val3' union select 3, 'val4'
+    on duplicate key update ts=now();
+select * from t1;
+pk	val	ts
+1	val1	2000-10-20 00:00:00
+2	val3	2000-10-20 01:00:00
+3	val4	2000-10-20 01:00:00
+set timestamp=unix_timestamp('2000-10-20 2:0:0');
+insert t1 (pk, val) select 1, 'val1' union select 4, 'val2'
+    on duplicate key update ts=now();
+select * from t1;
+pk	val	ts
+1	val1	2000-10-20 02:00:00
+2	val3	2000-10-20 01:00:00
+3	val4	2000-10-20 01:00:00
+4	val2	2000-10-20 02:00:00
+set timestamp=unix_timestamp('2000-10-20 3:0:0');
+insert t1 (pk, val) select 5, 'val1' union select 1, 'val2'
+    on duplicate key update ts=now();
+select * from t1;
+pk	val	ts
+1	val1	2000-10-20 03:00:00
+2	val3	2000-10-20 01:00:00
+3	val4	2000-10-20 01:00:00
+4	val2	2000-10-20 02:00:00
+5	val1	2000-10-20 03:00:00
+drop table t1;
+set timestamp=default;
+#
+# End of 10.4 tests
+#

mysql-test/main/insert_update.test

@@ -311,3 +311,29 @@ insert into t1(f1) values(1) on duplicate key update f1=1;
 select @stamp2:=f2 from t1;
 select if( @stamp1 = @stamp2, "correct", "wrong");
 drop table t1;
+
+--echo #
+--echo # MDEV-31164 default current_timestamp() not working when used INSERT ON DUPLICATE KEY in some cases
+--echo #
+set timestamp=unix_timestamp('2000-10-20 0:0:0');
+create table t1 (pk integer primary key, val varchar(20) not null, ts timestamp);
+insert t1 (pk, val) values(1, 'val1');
+select * from t1;
+set timestamp=unix_timestamp('2000-10-20 1:0:0');
+insert t1 (pk, val) select 2, 'val3' union select 3, 'val4'
+    on duplicate key update ts=now();
+select * from t1;
+set timestamp=unix_timestamp('2000-10-20 2:0:0');
+insert t1 (pk, val) select 1, 'val1' union select 4, 'val2'
+    on duplicate key update ts=now();
+select * from t1;
+set timestamp=unix_timestamp('2000-10-20 3:0:0');
+insert t1 (pk, val) select 5, 'val1' union select 1, 'val2'
+    on duplicate key update ts=now();
+select * from t1;
+drop table t1;
+set timestamp=default;
+
+--echo #
+--echo # End of 10.4 tests
+--echo #

sql/sql_insert.cc

@@ -4028,6 +4028,7 @@ bool select_insert::store_values(List<Item> &values)
   DBUG_ENTER("select_insert::store_values");
   bool error;
 
+  table->reset_default_fields();
   if (fields->elements)
     error= fill_record_n_invoke_before_triggers(thd, table, *fields, values,
                                                 true, TRG_EVENT_INSERT);