MDEV-8605 MariaDB not use DEFAULT value even when inserted NULL for NOT NULLABLE column

NOT NULL constraint must be checked *after* the BEFORE triggers.
That is for INSERT and UPDATE statements even NOT NULL fields
must be able to store a NULL temporarily at least while
BEFORE INSERT/UPDATE triggers are running.

1 files changed, 3 insertions, 0 deletions

diff --git a/sql/item.h b/sql/item.h
index e262ce9d12d..d5b6463d91a 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1605,6 +1605,8 @@ public:
 
   virtual bool check_inner_refs_processor(uchar *arg) { return FALSE; }
 
+  virtual bool switch_to_nullable_fields_processor(uchar *arg) { return FALSE; }
+
   /*
     For SP local variable returns pointer to Item representing its
     current value and pointer to current Item otherwise.
@@ -2464,6 +2466,7 @@ public:
   bool vcol_in_partition_func_processor(uchar *bool_arg);
   bool enumerate_field_refs_processor(uchar *arg);
   bool update_table_bitmaps_processor(uchar *arg);
+  bool switch_to_nullable_fields_processor(uchar *arg);
   void cleanup();
   Item_equal *get_item_equal() { return item_equal; }
   void set_item_equal(Item_equal *item_eq) { item_equal= item_eq; }