Bug #44792: valgrind warning when casting from time to time

 
Field_time::get_time() did not initialize some members of 
MYSQL_TIME which led to valgrind warnings when those members 
were accessed in Protocol_simple::store_time(). 
 
It is unlikely that this bug could result in wrong data 
being returned, since Field_time::get_time() initializes the 
'day' member of MYSQL_TIME to 0, so the value of 'day' 
in Protocol_simple::store_time() would be 0 regardless 
of the values for 'year' and 'month'.

mysql-test/r/type_time.result

@@ -128,3 +128,13 @@ SELECT sum(f3) FROM t1 where f2='2007-07-01 00:00:00' group by f2;
 sum(f3)
 3
 drop table t1;
+#
+# Bug #44792: valgrind warning when casting from time to time
+#
+CREATE TABLE t1 (c TIME);
+INSERT INTO t1 VALUES ('0:00:00');
+SELECT CAST(c AS TIME) FROM t1;
+CAST(c AS TIME)
+00:00:00
+DROP TABLE t1;
+End of 5.0 tests

mysql-test/t/type_time.test

@@ -77,3 +77,16 @@ insert into t1 values('2007-07-02', 1);
 insert into t1 values('2007-07-02', 2);
 SELECT sum(f3) FROM t1 where f2='2007-07-01 00:00:00' group by f2;
 drop table t1;
+
+
+--echo #
+--echo # Bug #44792: valgrind warning when casting from time to time
+--echo #
+
+CREATE TABLE t1 (c TIME);
+INSERT INTO t1 VALUES ('0:00:00');
+SELECT CAST(c AS TIME) FROM t1;
+DROP TABLE t1;
+
+
+--echo End of 5.0 tests

sql/field.cc

@@ -4877,7 +4877,7 @@ bool Field_time::get_time(MYSQL_TIME *ltime)
     ltime->neg= 1;
     tmp=-tmp;
   }
-  ltime->day= 0;
+  ltime->year= ltime->month= ltime->day= 0;
   ltime->hour=   (int) (tmp/10000);
   tmp-=ltime->hour*10000;
   ltime->minute= (int) tmp/100;