MDEV-13673 Bad result in view

When printing an expression, like a/(b*c), we need to print parentheses,
even though / and * have the same precedence. Basically, we should
always treat the second argument as having one level higher precedence
than it normally is.

Author: vuvova

mysql-test/r/func_math.result

@@ -838,3 +838,8 @@ select 0=0, 0=-0, 0.0= -0.0, 0.0 = -(0.0), 0.0E1=-0.0E1, 0.0E1=-(0.0E1);
 select CRC32(NULL), CRC32(''), CRC32('MySQL'), CRC32('mysql'), CRC32('01234567'), CRC32('012345678');
 CRC32(NULL)	CRC32('')	CRC32('MySQL')	CRC32('mysql')	CRC32('01234567')	CRC32('012345678')
 NULL	0	3259397556	2501908538	763378421	939184570
+explain extended select (3-2)+1, (3/2)*1, 3-(2+1), 3/(2*1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+Warnings:
+Note	1003	select 3 - 2 + 1 AS `(3-2)+1`,3 / 2 * 1 AS `(3/2)*1`,3 - (2 + 1) AS `3-(2+1)`,3 / (2 * 1) AS `3/(2*1)`

mysql-test/r/select.result

@@ -4784,7 +4784,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + 1 + 1)
+Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + (1 + 1))
 SELECT * FROM t2 LEFT JOIN t1 ON a = b + 1;
 b	a
 2	3

mysql-test/r/select_jcl6.result

@@ -4795,7 +4795,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + 1 + 1)
+Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + (1 + 1))
 SELECT * FROM t2 LEFT JOIN t1 ON a = b + 1;
 b	a
 2	3

mysql-test/r/select_pkeycache.result

@@ -4784,7 +4784,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + 1 + 1)
+Note	1003	select `test`.`t1`.`a` AS `a`,2 AS `b` from `test`.`t1` where `test`.`t1`.`a` = <cache>(2 + (1 + 1))
 SELECT * FROM t2 LEFT JOIN t1 ON a = b + 1;
 b	a
 2	3

mysql-test/t/func_math.test

@@ -608,3 +608,8 @@ select 0=0, 0=-0, 0.0= -0.0, 0.0 = -(0.0), 0.0E1=-0.0E1, 0.0E1=-(0.0E1);
 --echo #
 
 select CRC32(NULL), CRC32(''), CRC32('MySQL'), CRC32('mysql'), CRC32('01234567'), CRC32('012345678');
+
+#
+# MDEV-13673 Bad result in view
+#
+explain extended select (3-2)+1, (3/2)*1, 3-(2+1), 3/(2*1);

sql/item_func.cc

@@ -479,7 +479,8 @@ void Item_func::print_op(String *str, enum_query_type query_type)
     str->append(func_name());
     str->append(' ');
   }
-  args[arg_count-1]->print_parenthesised(str, query_type, precedence());
+  args[arg_count-1]->print_parenthesised(str, query_type,
+                                         (enum precedence)(precedence() + 1));
 }