* fix for ALTER TABLE ... MODIFY timestamp->timestamp.

Use dedicated  do_field_temporal() for Copy_field.
* check_time_range() needs to know TIME's precision to use the
  correct max value.

include/my_time.h

@@ -92,7 +92,7 @@ double TIME_to_double(const MYSQL_TIME *my_time);
 longlong pack_time(MYSQL_TIME *my_time);
 MYSQL_TIME *unpack_time(longlong packed, MYSQL_TIME *my_time);
 
-int check_time_range(struct st_mysql_time *, int *warning);
+int check_time_range(struct st_mysql_time *my_time, uint dec, int *warning);
 
 long calc_daynr(uint year,uint month,uint day);
 uint calc_days_in_year(uint year);

mysql-test/r/func_time_hires.result

@@ -158,6 +158,14 @@ select time(f1) from t1 union all select time(f1) from t1;
 time(f1)
 21:00:00.000000
 21:00:00.000000
+alter table t1 modify f1 timestamp;
+select time(f1) from t1;
+time(f1)
+21:00:00
+select time(f1) from t1 union all select time(f1) from t1;
+time(f1)
+21:00:00
+21:00:00
 alter table t1 modify f1 varchar(100);
 select time(f1) from t1;
 time(f1)

mysql-test/t/func_time_hires.test

@@ -86,9 +86,9 @@ create table t1 (f1 timestamp(6));
 insert into t1 values ('2002-07-15 21:00:00');
 select time(f1) from t1;
 select time(f1) from t1 union all select time(f1) from t1;
-#alter table t1 modify f1 timestamp;
-#select time(f1) from t1;
-#select time(f1) from t1 union all select time(f1) from t1;
+alter table t1 modify f1 timestamp;
+select time(f1) from t1;
+select time(f1) from t1 union all select time(f1) from t1;
 # but the effect cannot be eliminated completely:
 alter table t1 modify f1 varchar(100);
 select time(f1) from t1;

sql-common/my_time.c

@@ -654,7 +654,7 @@ fractional:
   l_time->time_type= MYSQL_TIMESTAMP_TIME;
 
   /* Check if the value is valid and fits into MYSQL_TIME range */
-  if (check_time_range(l_time, warning))
+  if (check_time_range(l_time, 6, warning))
     return MYSQL_TIMESTAMP_ERROR;
   
   /* Check if there is garbage at end of the MYSQL_TIME specification */
@@ -679,6 +679,7 @@ fractional:
   SYNOPSIS:
     check_time_range()
     time     pointer to MYSQL_TIME value
+    uint     dec
     warning  set MYSQL_TIME_WARN_OUT_OF_RANGE flag if the value is out of range
 
   DESCRIPTION
@@ -691,17 +692,24 @@ fractional:
     1        time value is invalid
 */
 
-int check_time_range(struct st_mysql_time *my_time, int *warning) 
+int check_time_range(struct st_mysql_time *my_time, uint dec, int *warning) 
 {
   longlong hour;
+  static ulong max_sec_part[MAX_SEC_PART_DIGITS+1]= {000000, 900000, 990000,
+                                             999000, 999900, 999990, 999999};
 
   if (my_time->minute >= 60 || my_time->second >= 60)
     return 1;
 
   hour= my_time->hour + (24*my_time->day);
+
+  if (dec == AUTO_SEC_PART_DIGITS)
+    dec= MAX_SEC_PART_DIGITS;
+
   if (hour <= TIME_MAX_HOUR &&
       (hour != TIME_MAX_HOUR || my_time->minute != TIME_MAX_MINUTE ||
-       my_time->second != TIME_MAX_SECOND || !my_time->second_part))
+       my_time->second != TIME_MAX_SECOND ||
+       my_time->second_part <= max_sec_part[dec]))
     return 0;
 
   my_time->day= 0;

sql/field.cc

@@ -5348,7 +5348,7 @@ int Field_time::store_time(MYSQL_TIME *ltime, timestamp_type time_type)
   Lazy_string_time str(ltime);
   int was_cut= 0;
 
-  int have_smth_to_conv= !check_time_range(&l_time, &was_cut);
+  int have_smth_to_conv= !check_time_range(&l_time, decimals(), &was_cut);
   return store_TIME_with_warning(&l_time, &str, was_cut, have_smth_to_conv);
 }
 

sql/field_conv.cc

@@ -365,6 +365,14 @@ static void do_field_decimal(Copy_field *copy)
 }
 
 
+static void do_field_temporal(Copy_field *copy)
+{
+  MYSQL_TIME ltime;
+  copy->from_field->get_date(&ltime, TIME_FUZZY_DATE);
+  copy->to_field->store_time(&ltime, ltime.time_type);
+}
+
+
 /**
   string copy for single byte characters set when to string is shorter than
   from string.
@@ -559,7 +567,7 @@ void Copy_field::set(uchar *to,Field *from)
 /*
   To do: 
 
-  If 'save\ is set to true and the 'from' is a blob field, do_copy is set to
+  If 'save' is set to true and the 'from' is a blob field, do_copy is set to
   do_save_blob rather than do_conv_blob.  The only differences between them
   appears to be:
 
@@ -657,6 +665,8 @@ Copy_field::get_copy_func(Field *to,Field *from)
       return do_field_int;
     if (to->result_type() == DECIMAL_RESULT)
       return do_field_decimal;
+    if (to->cmp_type() == TIME_RESULT)
+      return do_field_temporal;
     // Check if identical fields
     if (from->result_type() == STRING_RESULT)
     {

sql/item_timefunc.cc

@@ -2482,7 +2482,7 @@ bool Item_func_add_time::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
   MYSQL_TIME copy= *ltime;
   Lazy_string_time str(&copy);
 
-  check_time_range(ltime, &was_cut);
+  check_time_range(ltime, decimals, &was_cut);
   if (was_cut)
     make_truncated_value_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                                  &str, MYSQL_TIMESTAMP_TIME, NullS);
@@ -2561,7 +2561,7 @@ bool Item_func_timediff::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
     goto null_date;
 
   *ltime= l_time3;
-  check_time_range(ltime, &was_cut);
+  check_time_range(ltime, decimals, &was_cut);
 
   if (was_cut)
     make_truncated_value_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,