Fix for bugs #1885, #2464, #2539. Proper handling of default

values for TIMESTAMP columns. The solution is not perfect since
we just silently ignoring default value for first TIMESTAMP 
column and properly reflecting this fact in SHOW CREATE TABLE.
We can't give a warning or simply support standard syntax 
(niladic functions as legal value for default) for first field 
since it is 4.0 tree.


mysql-test/r/type_timestamp.result:
  Added test for bugs #1885, #2464, #2539
  (proper support of default values for TIMESTAMP columns)
mysql-test/t/type_timestamp.test:
  Added test for bugs #1885, #2464, #2539
  (proper support of default values for TIMESTAMP columns)
sql/field.cc:
  Enabled copying of defaults for TIMESTAMP fields when we are 
  creating table with CREATE TABLE x (SELECT ...)
sql/field.h:
  Set proper DEFAULT value for non-first TIMESTAMP column.
sql/sql_parse.cc:
  Allowed default values for TIMESTAMP column.
sql/sql_show.cc:
  Enabled printing of default values in SHOW CREATE TABLE and 
  SHOW COLUMNS for all TIMESTAMP columns except first one.

mysql-test/r/type_timestamp.result

@@ -122,5 +122,48 @@ t2	t4	t6	t8	t10	t12	t14
 0000-00-00 00:00:00	0000-00-00 00:00:00	0000-00-00 00:00:00	0000-00-00 00:00:00	0000-00-00 00:00:00	0000-00-00 00:00:00	0000-00-00 00:00:00
 1997-12-31 23:47:59	1997-12-31 23:47:59	1997-12-31 23:47:59	1997-12-31 23:47:59	1997-12-31 23:47:59	1997-12-31 23:47:59	1997-12-31 23:47:59
 drop table t1;
-create table t1 (a timestamp default 1);
-Invalid default value for 'a'
+create table t1 (t1 timestamp default '2003-01-01 00:00:00', 
+t2 timestamp default '2003-01-01 00:00:00');
+set TIMESTAMP=1000000000;
+insert into t1 values();
+select * from t1;
+t1	t2
+2001-09-09 04:46:40	2003-01-01 00:00:00
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `t1` timestamp(14) NOT NULL,
+  `t2` timestamp(14) NOT NULL default '2003-01-01 00:00:00'
+) TYPE=MyISAM
+show columns from t1;
+Field	Type	Null	Key	Default	Extra
+t1	timestamp(14)	YES		NULL	
+t2	timestamp(14)	YES		2003-01-01 00:00:00	
+show columns from t1 like 't2';
+Field	Type	Null	Key	Default	Extra
+t2	timestamp(14)	YES		2003-01-01 00:00:00	
+create table t2 (select * from t1);
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `t1` timestamp(14) NOT NULL,
+  `t2` timestamp(14) NOT NULL default '2003-01-01 00:00:00'
+) TYPE=MyISAM
+alter table t1 add column t0 timestamp first;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `t0` timestamp(14) NOT NULL,
+  `t1` timestamp(14) NOT NULL default '2003-01-01 00:00:00',
+  `t2` timestamp(14) NOT NULL default '2003-01-01 00:00:00'
+) TYPE=MyISAM
+drop table t1,t2;
+create table t1 (ts1 timestamp, ts2 timestamp);
+set TIMESTAMP=1000000000;
+insert into t1 values ();
+insert into t1 values (DEFAULT, DEFAULT);
+select * from t1;
+ts1	ts2
+2001-09-09 04:46:40	0000-00-00 00:00:00
+2001-09-09 04:46:40	0000-00-00 00:00:00
+drop table t1;

mysql-test/t/type_timestamp.test

@@ -73,8 +73,35 @@ select * from t1;
 drop table t1;
 
 #
-# Bug #1885
+# Bug #1885, bug #2539. 
+# Not perfect but still sensible attitude towards defaults for TIMESTAMP
+# We will ignore default value for first TIMESTAMP column.
 #
+create table t1 (t1 timestamp default '2003-01-01 00:00:00', 
+                 t2 timestamp default '2003-01-01 00:00:00');
+set TIMESTAMP=1000000000;
+insert into t1 values();
+select * from t1;
+show create table t1;
+show columns from t1;
+show columns from t1 like 't2';
+create table t2 (select * from t1);
+show create table t2;
+
+# Ugly, but we can't do anything about this in 4.0
+alter table t1 add column t0 timestamp first;
+show create table t1;
 
---error 1067
-create table t1 (a timestamp default 1);
+drop table t1,t2;
+
+#
+# Test for bug 2464, DEFAULT keyword in INSERT statement should return
+# default value for column.
+#
+
+create table t1 (ts1 timestamp, ts2 timestamp);
+set TIMESTAMP=1000000000;
+insert into t1 values ();
+insert into t1 values (DEFAULT, DEFAULT);
+select * from t1;
+drop table t1;

sql/field.cc

@@ -5124,8 +5124,7 @@ create_field::create_field(Field *old_field,Field *orig_field)
     interval=0;
   def=0;
   if (!old_field->is_real_null() && ! (flags & BLOB_FLAG) &&
-      old_field->type() != FIELD_TYPE_TIMESTAMP && old_field->ptr &&
-      orig_field)
+      old_field->ptr && orig_field)
   {
     char buff[MAX_FIELD_WIDTH],*pos;
     String tmp(buff,sizeof(buff));

sql/field.h

@@ -564,7 +564,10 @@ public:
   void set_time();
   virtual void set_default()
   {
-    set_time();
+    if (table->timestamp_field == this)
+      set_time();
+    else
+      Field::set_default();
   }
   inline long get_timestamp()
   {

sql/sql_parse.cc

@@ -3056,12 +3056,12 @@ bool add_field_to_list(char *field_name, enum_field_types type,
 
   if (default_value)
   {
-    if (type == FIELD_TYPE_TIMESTAMP)
-    {
-      net_printf(&thd->net, ER_INVALID_DEFAULT, field_name);
-      DBUG_RETURN(1);
-    }
-    else if (default_value->type() == Item::NULL_ITEM)
+    /*
+      We allow specifying value for first TIMESTAMP column 
+      altough it is silently ignored. This should be fixed in 4.1
+      (by proper warning or real support for default values)
+    */
+    if (default_value->type() == Item::NULL_ITEM)
     {
       default_value=0;
       if ((type_modifier & (NOT_NULL_FLAG | AUTO_INCREMENT_FLAG)) ==

sql/sql_show.cc

@@ -508,6 +508,12 @@ mysqld_show_fields(THD *thd, TABLE_LIST *table_list,const char *wild,
         field->sql_type(type);
         net_store_data(packet,convert,type.ptr(),type.length());
 
+        /*
+          Altough TIMESTAMP fields can't contain NULL as its value they
+          will accept NULL if you will try to insert such value and will
+          convert it to current TIMESTAMP. So YES here means that NULL 
+          is allowed for assignment but can't be returned.
+        */
         pos=(byte*) ((flags & NOT_NULL_FLAG) &&
                      field->type() != FIELD_TYPE_TIMESTAMP ?
                      "" : "YES");
@@ -517,7 +523,11 @@ mysqld_show_fields(THD *thd, TABLE_LIST *table_list,const char *wild,
                      (field->flags & MULTIPLE_KEY_FLAG) ? "MUL":"");
         net_store_data(packet,convert,(char*) pos);
 
-        if (field->type() == FIELD_TYPE_TIMESTAMP ||
+        /*
+          We handle first TIMESTAMP column in special way because its
+          default value is ignored and current timestamp used instead.
+        */
+        if (table->timestamp_field == field ||
             field->unireg_check == Field::NEXT_NUMBER)
           null_default_value=1;
         if (!null_default_value && !field->is_null())
@@ -888,7 +898,7 @@ store_create_info(THD *thd, TABLE *table, String *packet)
     packet->append(type.ptr(),type.length());
 
     has_default= (field->type() != FIELD_TYPE_BLOB &&
-		  field->type() != FIELD_TYPE_TIMESTAMP &&
+		  table->timestamp_field != field &&
 		  field->unireg_check != Field::NEXT_NUMBER);
     if (flags & NOT_NULL_FLAG)
       packet->append(" NOT NULL", 9);