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, 10 insertions, 1 deletions

diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 0caae7ac821..f343a17ee11 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -455,6 +455,8 @@ int mysql_update(THD *thd,
   }
   init_ftfuncs(thd, select_lex, 1);
 
+  switch_to_nullable_trigger_fields(fields, table);
+  switch_to_nullable_trigger_fields(values, table);
   table->mark_columns_needed_for_update();
 
   table->update_const_key_parts(conds);
@@ -1766,7 +1768,6 @@ int multi_update::prepare(List<Item> &not_used_values,
     }
   }
 
-
   table_count=  update.elements;
   update_tables= update.first;
 
@@ -1802,7 +1803,15 @@ int multi_update::prepare(List<Item> &not_used_values,
   /* Allocate copy fields */
   max_fields=0;
   for (i=0 ; i < table_count ; i++)
+  {
     set_if_bigger(max_fields, fields_for_table[i]->elements + leaf_table_count);
+    if (fields_for_table[i]->elements)
+    {
+      TABLE *table= ((Item_field*)(fields_for_table[i]->head()))->field->table;
+      switch_to_nullable_trigger_fields(*fields_for_table[i], table);
+      switch_to_nullable_trigger_fields(*values_for_table[i], table);
+    }
+  }
   copy_field= new Copy_field[max_fields];
   DBUG_RETURN(thd->is_fatal_error != 0);
 }