MDEV-22268 virtual longlong Item_func_div::int_op(): Assertion `0' failed in Item_func_div::int_op

Item_func_div::fix_length_and_dec_temporal() set the return data type to
integer in case of @div_precision_increment==0 for temporal input with FSP=0.
This caused Item_func_div to call int_op(), which is not implemented,
so a crash on DBUG_ASSERT(0) happened.

Fixing fix_length_and_dec_temporal() to set the result type to DECIMAL.

mysql-test/main/func_math.result

@@ -2251,5 +2251,35 @@ SELECT ROUND( i, 18446744073709551594 ) AS f FROM t1;
 f
 DROP TABLE t1;
 #
+# MDEV-22268 virtual longlong Item_func_div::int_op(): Assertion `0' failed in Item_func_div::int_op
+#
+SET sql_mode='';
+SET @@SESSION.div_precision_increment=0;
+SELECT UTC_TIME / 0;
+UTC_TIME / 0
+NULL
+SELECT TIMESTAMP'2001-01-01 00:00:00'/0;
+TIMESTAMP'2001-01-01 00:00:00'/0
+NULL
+SELECT TIME'00:00:00'/0;
+TIME'00:00:00'/0
+NULL
+CREATE TABLE t1 AS SELECT
+UTC_TIME / 0 AS c1,
+TIMESTAMP'2001-01-01 00:00:00'/0 AS c3,
+TIME'00:00:00'/0 AS c4;
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` decimal(7,0) DEFAULT NULL,
+  `c3` decimal(14,0) DEFAULT NULL,
+  `c4` decimal(7,0) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+SELECT(-0 * MOD((UTC_TIME / -0)MOD (ATAN('<img src_x0=x onerror="javascript:alert(0)">') MOD COT(0)),-0)) MOD (0 DIV 0);
+ERROR 22003: DOUBLE value is out of range in 'cot(0)'
+SET @@SESSION.div_precision_increment=DEFAULT;
+SET sql_mode=DEFAULT;
+#
 # End of 10.3 tests
 #

mysql-test/main/func_math.test

@@ -1111,6 +1111,29 @@ CREATE TABLE t1 (i INT(23));
 SELECT ROUND( i, 18446744073709551594 ) AS f FROM t1;
 DROP TABLE t1;
 
+
+--echo #
+--echo # MDEV-22268 virtual longlong Item_func_div::int_op(): Assertion `0' failed in Item_func_div::int_op
+--echo #
+
+SET sql_mode='';
+SET @@SESSION.div_precision_increment=0;
+SELECT UTC_TIME / 0;
+SELECT TIMESTAMP'2001-01-01 00:00:00'/0;
+SELECT TIME'00:00:00'/0;
+CREATE TABLE t1 AS SELECT
+  UTC_TIME / 0 AS c1,
+  TIMESTAMP'2001-01-01 00:00:00'/0 AS c3,
+  TIME'00:00:00'/0 AS c4;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+--error ER_DATA_OUT_OF_RANGE
+SELECT(-0 * MOD((UTC_TIME / -0)MOD (ATAN('<img src_x0=x onerror="javascript:alert(0)">') MOD COT(0)),-0)) MOD (0 DIV 0);
+
+SET @@SESSION.div_precision_increment=DEFAULT;
+SET sql_mode=DEFAULT;
+
 --echo #
 --echo # End of 10.3 tests
 --echo #

sql/item_func.h

@@ -754,11 +754,11 @@ class Item_num_op :public Item_func_numhybrid
     decimals= 0;
     set_handler(type_handler_long_or_longlong());
   }
-  void fix_length_and_dec_temporal()
+  void fix_length_and_dec_temporal(bool downcast_decimal_to_int)
   {
     set_handler(&type_handler_newdecimal);
     fix_length_and_dec_decimal();
-    if (decimals == 0)
+    if (decimals == 0 && downcast_decimal_to_int)
       set_handler(type_handler_long_or_longlong());
   }
   bool need_parentheses_in_default() { return true; }

sql/sql_type.cc

@@ -4772,7 +4772,7 @@ bool Type_handler_decimal_result::
 bool Type_handler_temporal_result::
        Item_func_plus_fix_length_and_dec(Item_func_plus *item) const
 {
-  item->fix_length_and_dec_temporal();
+  item->fix_length_and_dec_temporal(true);
   return false;
 }
 
@@ -4821,7 +4821,7 @@ bool Type_handler_decimal_result::
 bool Type_handler_temporal_result::
        Item_func_minus_fix_length_and_dec(Item_func_minus *item) const
 {
-  item->fix_length_and_dec_temporal();
+  item->fix_length_and_dec_temporal(true);
   return false;
 }
 
@@ -4870,7 +4870,7 @@ bool Type_handler_decimal_result::
 bool Type_handler_temporal_result::
        Item_func_mul_fix_length_and_dec(Item_func_mul *item) const
 {
-  item->fix_length_and_dec_temporal();
+  item->fix_length_and_dec_temporal(true);
   return false;
 }
 
@@ -4919,7 +4919,8 @@ bool Type_handler_decimal_result::
 bool Type_handler_temporal_result::
        Item_func_div_fix_length_and_dec(Item_func_div *item) const
 {
-  item->fix_length_and_dec_temporal();
+  // Item_func_div::int_op() is not implemented. Disallow DECIMAL->INT downcast.
+  item->fix_length_and_dec_temporal(false);
   return false;
 }
 
@@ -4968,7 +4969,7 @@ bool Type_handler_decimal_result::
 bool Type_handler_temporal_result::
        Item_func_mod_fix_length_and_dec(Item_func_mod *item) const
 {
-  item->fix_length_and_dec_temporal();
+  item->fix_length_and_dec_temporal(true);
   return false;
 }