function DEFAULT(x) now works for expression defaults

2 files changed, 59 insertions, 4 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 7c93c5eed73..c4385b99d39 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -8211,8 +8211,7 @@ bool Item_default_value::fix_fields(THD *thd, Item **items)
   }
 
   field_arg= (Item_field *)real_arg;
-  if ((field_arg->field->flags & NO_DEFAULT_VALUE_FLAG) ||
-      field_arg->field->default_value)
+  if ((field_arg->field->flags & NO_DEFAULT_VALUE_FLAG))
   {
     my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);
     goto error;
@@ -8225,6 +8224,12 @@ bool Item_default_value::fix_fields(THD *thd, Item **items)
                                (def_field->table->s->default_values -
                                 def_field->table->record[0]));
   set_field(def_field);
+  if (field->default_value)
+  {
+    if (field->default_value->expr_item) // it's NULL during CREATE TABLE
+      field->default_value->expr_item->walk(&Item::register_field_in_read_map, 1, 0);
+    IF_DBUG(def_field->is_stat_field=1,); // a hack to fool ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED
+  }
   return FALSE;
 
 error:
@@ -8245,10 +8250,53 @@ void Item_default_value::print(String *str, enum_query_type query_type)
   str->append(')');
 }
 
+void Item_default_value::calculate()
+{
+  if (field->default_value || field->has_insert_default_function())
+    field->set_default();
+}
+
+String *Item_default_value::val_str(String *str)
+{
+  calculate();
+  return Item_field::val_str(str);
+}
+
+double Item_default_value::val_real()
+{
+  calculate();
+  return Item_field::val_real();
+}
+
+longlong Item_default_value::val_int()
+{
+  calculate();
+  return Item_field::val_int();
+}
+
+my_decimal *Item_default_value::val_decimal(my_decimal *decimal_value)
+{
+  calculate();
+  return Item_field::val_decimal(decimal_value);
+}
+
+bool Item_default_value::get_date(MYSQL_TIME *ltime,ulonglong fuzzydate)
+{
+  calculate();
+  return Item_field::get_date(ltime, fuzzydate);
+}
+
+bool Item_default_value::send(Protocol *protocol, String *buffer)
+{
+  calculate();
+  return Item_field::send(protocol, buffer);
+}
 
 int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)
 {
-  if (!arg)
+  if (arg)
+    calculate();
+  else
   {
     TABLE *table= field_arg->table;
     THD *thd= table->in_use;
diff --git a/sql/item.h b/sql/item.h
index 0a526e09bed..9794d987be1 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -4877,6 +4877,7 @@ public:
 
 class Item_default_value : public Item_field
 {
+  void calculate();
 public:
   Item *arg;
   Item_default_value(THD *thd, Name_resolution_context *context_arg)
@@ -4890,7 +4891,13 @@ public:
   enum Type type() const { return DEFAULT_VALUE_ITEM; }
   bool eq(const Item *item, bool binary_cmp) const;
   bool fix_fields(THD *, Item **);
-  virtual void print(String *str, enum_query_type query_type);
+  void print(String *str, enum_query_type query_type);
+  String *val_str(String *str);
+  double val_real();
+  longlong val_int();
+  my_decimal *val_decimal(my_decimal *decimal_value);
+  bool get_date(MYSQL_TIME *ltime,ulonglong fuzzydate);
+  bool send(Protocol *protocol, String *buffer);
   int save_in_field(Field *field_arg, bool no_conversions);
   table_map used_tables() const { return (table_map)0L; }