backport for #10568: Function 'LAST_DAY(date)' does not return NULL for invalid argument.

mysql-test/r/func_time.result

@@ -611,3 +611,18 @@ SELECT count(*) FROM t1 WHERE d>FROM_DAYS(TO_DAYS(@TMP)) AND d<=FROM_DAYS(TO_DAY
 count(*)
 3
 DROP TABLE t1;
+select last_day('2005-00-00');
+last_day('2005-00-00')
+NULL
+Warnings:
+Warning	1292	Truncated incorrect datetime value: '2005-00-00'
+select last_day('2005-00-01');
+last_day('2005-00-01')
+NULL
+Warnings:
+Warning	1292	Truncated incorrect datetime value: '2005-00-01'
+select last_day('2005-01-00');
+last_day('2005-01-00')
+NULL
+Warnings:
+Warning	1292	Truncated incorrect datetime value: '2005-01-00'

mysql-test/t/func_time.test

@@ -307,3 +307,10 @@ INSERT INTO t1 VALUES (NOW());
 SELECT count(*) FROM t1 WHERE d>FROM_DAYS(TO_DAYS(@TMP)) AND d<=FROM_DAYS(TO_DAYS(@TMP)+1);
 DROP TABLE t1;
 
+#
+# Bug #10568
+#
+
+select last_day('2005-00-00');
+select last_day('2005-00-01');
+select last_day('2005-01-00');

sql/item_timefunc.cc

@@ -2817,7 +2817,7 @@ String *Item_func_str_to_date::val_str(String *str)
 
 bool Item_func_last_day::get_date(TIME *ltime, uint fuzzy_date)
 {
-  if (get_arg0_date(ltime,fuzzy_date))
+  if (get_arg0_date(ltime, fuzzy_date & ~TIME_FUZZY_DATE))
     return 1;
   uint month_idx= ltime->month-1;
   ltime->day= days_in_month[month_idx];