Fix for BUG#1960 "date_format() returns spurious '-' for valid dates".

It was a forgotten ltime->neg=0 (neg was the only forgotten variable).
I scanned field.cc for other places where we would forget to set neg, found none.
A test for the bug.


mysql-test/r/date_formats.result:
  result update
mysql-test/t/date_formats.test:
  a test for BUG#1960 "date_format() returns spurious '-' for valid dates"
sql/field.cc:
  When preparing ltime from the 3-byte date, don't forget to set ltime->neg to 0
  (otherwise it remains unitialized).
  Dates are not allowed to be negative (only times can be, when they mean a time interval),
  so it's ok to always set neg to 0.

mysql-test/r/date_formats.result

@@ -330,3 +330,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	select high_priority makedate(1997,1) AS `makedate(1997,1)`,addtime(_latin1'31.12.97 11.59.59.999999 PM',_latin1'31.12.97 11.59.59.999999 PM') AS `addtime("31.12.97 11.59.59.999999 PM", "1 1.1.1.000002")`,subtime(_latin1'31.12.97 11.59.59.999999 PM',_latin1'31.12.97 11.59.59.999999 PM') AS `subtime("31.12.97 11.59.59.999999 PM", "1 1.1.1.000002")`,timediff(_latin1'01.01.97 11:59:59.000001 PM',_latin1'31.12.95 11:59:59.000002 PM') AS `timediff("01.01.97 11:59:59.000001 PM","31.12.95 11:59:59.000002 PM")`,cast(str_to_date(_latin1'15-01-2001 12:59:59',_latin1'%d-%m-%Y %H:%i:%S') as time) AS `cast(str_to_date("15-01-2001 12:59:59", "%d-%m-%Y %H:%i:%S") as TIME)`,maketime(23,11,12) AS `maketime(23,11,12)`,microsecond(_latin1'1997-12-31 23:59:59.000001') AS `microsecond("1997-12-31 23:59:59.000001")`
+create table t1 (d date);
+insert into t1 values ('2004-07-14'),('2005-07-14');
+select date_format(d,"%d") from t1 order by 1;
+date_format(d,"%d")
+14
+14
+drop table t1;

mysql-test/t/date_formats.test

@@ -200,3 +200,12 @@ select get_format(DATE, 'TEST') as a;
 select str_to_date('15-01-2001 12:59:59', GET_FORMAT(DATE,'USA'));
 
 explain extended select makedate(1997,1), addtime("31.12.97 11.59.59.999999 PM", "1 1.1.1.000002"),subtime("31.12.97 11.59.59.999999 PM", "1 1.1.1.000002"),timediff("01.01.97 11:59:59.000001 PM","31.12.95 11:59:59.000002 PM"),cast(str_to_date("15-01-2001 12:59:59", "%d-%m-%Y %H:%i:%S") as TIME), maketime(23,11,12),microsecond("1997-12-31 23:59:59.000001");
+
+#
+# Test of date_format()
+#
+
+create table t1 (d date);
+insert into t1 values ('2004-07-14'),('2005-07-14');
+select date_format(d,"%d") from t1 order by 1;
+drop table t1;

sql/field.cc

@@ -3757,7 +3757,7 @@ bool Field_newdate::get_date(TIME *ltime,uint fuzzydate)
   ltime->month= (tmp >> 5) & 15;
   ltime->year=  (tmp >> 9);
   ltime->time_type=TIMESTAMP_DATE;
-  ltime->hour= ltime->minute= ltime->second= ltime->second_part= 0;
+  ltime->hour= ltime->minute= ltime->second= ltime->second_part= ltime->neg= 0;
   return (!fuzzydate && (!ltime->month || !ltime->day)) ? 1 : 0;
 }