MDEV-15626 Assertion on update virtual column in partitioned table

table.cc:
  virtual columns must be computed for INSERT, if they're part
  of the partitioning expression.

this change broke gcol.gcol_partition_innodb.
fix CHECK TABLE for partitioned tables and vcols.

sql_partition.cc:
  mark prerequisite base columns in full_part_field_set
ha_partition.cc
  initialize vcol_set accordingly

mysql-test/suite/vcol/r/partition.result

@@ -18,3 +18,13 @@ x
 15
 22
 DROP TABLE t1;
+create table t1 (i int, v int as (i) virtual)
+partition by range columns (i)
+subpartition by hash(v) subpartitions 3 (
+partition p1 values less than (3),
+partition pn values less than (maxvalue));
+insert t1 set i= 0;
+set statement sql_mode= '' for update t1 set i= 1, v= 2;
+Warnings:
+Warning	1906	The value specified for generated column 'v' in table 't1' ignored
+drop table t1;

mysql-test/suite/vcol/t/partition.test

@@ -18,3 +18,15 @@ INSERT t1 (id, store_id) VALUES(1, 2), (3, 4), (3, 12), (4, 18);
 CREATE INDEX idx ON t1(x);
 SELECT x FROM t1;
 DROP TABLE t1;
+
+#
+# MDEV-15626 Assertion on update virtual column in partitioned table
+#
+create table t1 (i int, v int as (i) virtual)
+partition by range columns (i)
+subpartition by hash(v) subpartitions 3 (
+    partition p1 values less than (3),
+    partition pn values less than (maxvalue));
+insert t1 set i= 0;
+set statement sql_mode= '' for update t1 set i= 1, v= 2;
+drop table t1;

sql/ha_partition.cc

@@ -8877,6 +8877,8 @@ int ha_partition::check_misplaced_rows(uint read_part_id, bool do_repair)
   {
     /* Only need to read the partitioning fields. */
     bitmap_union(table->read_set, &m_part_info->full_part_field_set);
+    if (table->vcol_set)
+      bitmap_union(table->vcol_set, &m_part_info->full_part_field_set);
   }
 
   if ((result= m_file[read_part_id]->ha_rnd_init(1)))

sql/sql_partition.cc

@@ -614,9 +614,16 @@ static bool create_full_part_field_array(THD *thd, TABLE *table,
     full_part_field_array may be NULL if storage engine supports native
     partitioning.
   */
+  table->vcol_set= table->read_set= &part_info->full_part_field_set;
   if ((ptr= part_info->full_part_field_array))
     for (; *ptr; ptr++)
-      bitmap_set_bit(&part_info->full_part_field_set, (*ptr)->field_index);
+    {
+      if ((*ptr)->vcol_info)
+        table->mark_virtual_col(*ptr);
+      else
+        bitmap_fast_test_and_set(table->read_set, (*ptr)->field_index);
+    }
+  table->default_column_bitmaps();
 
 end:
   DBUG_RETURN(result);

sql/table.cc

@@ -6629,7 +6629,7 @@ bool TABLE::mark_virtual_columns_for_write(bool insert_fl)
     if (bitmap_is_set(write_set, tmp_vfield->field_index))
       bitmap_updated= mark_virtual_col(tmp_vfield);
     else if (tmp_vfield->vcol_info->stored_in_db ||
-             (tmp_vfield->flags & PART_KEY_FLAG))
+             (tmp_vfield->flags & (PART_KEY_FLAG | FIELD_IN_PART_FUNC_FLAG)))
     {
       if (insert_fl)
       {