MDEV-10817 CAST(MAX(DATE'2001-01-01') AS TIME) returns a wrong result

mysql-test/r/type_time.result

@@ -1245,5 +1245,19 @@ a	b	c
 2070	00:00:00	00:00:00
 DROP TABLE t1,t2;
 #
+# MDEV-10817 CAST(MAX(DATE'2001-01-01') AS TIME) returns a wrong result
+#
+SELECT CAST(DATE'2001-01-01' AS TIME);
+CAST(DATE'2001-01-01' AS TIME)
+00:00:00
+SELECT CAST(MAX(DATE'2001-01-01') AS TIME);
+CAST(MAX(DATE'2001-01-01') AS TIME)
+00:00:00
+CREATE FUNCTION f1() RETURNS DATE RETURN DATE'2001-01-01';
+SELECT CAST(f1() AS TIME);
+CAST(f1() AS TIME)
+00:00:00
+DROP FUNCTION  f1;
+#
 # End of 10.2 tests
 #

mysql-test/t/type_time.test

@@ -746,6 +746,17 @@ SELECT * FROM t1;
 DROP TABLE t1,t2;
 
 
+--echo #
+--echo # MDEV-10817 CAST(MAX(DATE'2001-01-01') AS TIME) returns a wrong result
+--echo #
+
+SELECT CAST(DATE'2001-01-01' AS TIME);
+SELECT CAST(MAX(DATE'2001-01-01') AS TIME);
+CREATE FUNCTION f1() RETURNS DATE RETURN DATE'2001-01-01';
+SELECT CAST(f1() AS TIME);
+DROP FUNCTION  f1;
+
+
 --echo #
 --echo # End of 10.2 tests
 --echo #

sql/item_func.h

@@ -2367,6 +2367,13 @@ class Item_func_sp :public Item_func
     return sp_result_field->val_decimal(dec_buf);
   }
 
+  bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate)
+  {
+    if (execute())
+      return true;
+    return sp_result_field->get_date(ltime, fuzzydate);
+  }
+
   String *val_str(String *str)
   {
     String buf;

sql/item_sum.cc

@@ -2065,6 +2065,18 @@ void Item_sum_hybrid::clear()
   null_value= 1;
 }
 
+bool
+Item_sum_hybrid::get_date(MYSQL_TIME *ltime, ulonglong fuzzydate)
+{
+  DBUG_ASSERT(fixed == 1);
+  if (null_value)
+    return 0;
+  bool retval= value->get_date(ltime, fuzzydate);
+  if ((null_value= value->null_value))
+    DBUG_ASSERT(retval == true);
+  return retval;
+}
+
 double Item_sum_hybrid::val_real()
 {
   DBUG_ASSERT(fixed == 1);

sql/item_sum.h

@@ -1037,6 +1037,7 @@ class Item_sum_hybrid :public Item_sum, public Type_handler_hybrid_field_type
   double val_real();
   longlong val_int();
   my_decimal *val_decimal(my_decimal *);
+  bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
   void reset_field();
   String *val_str(String *);
   bool keep_field_type(void) const { return 1; }