MDEV-8671 Wrong result for SELECT..WHERE varchar_column=' 1' AND (varchar_column XOR '1')

mysql-test/r/ctype_cp1251.result

@@ -3363,5 +3363,31 @@ Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((`test`.`t1`.`a` = ' 1') and (`test`.`t1`.`a` in (1,2,3,'x')))
 DROP TABLE t1;
 #
+# MDEV-8671 Wrong result for SELECT..WHERE varchar_column=' 1' AND (varchar_column XOR '1')
+#
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET cp1251 COLLATE cp1251_ukrainian_ci);
+INSERT INTO t1 VALUES (' 1'),('`1');
+SELECT * FROM t1 WHERE a=' 1';
+a
+ 1
+`1
+SELECT * FROM t1 WHERE (a XOR '0');
+a
+ 1
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '`1'
+SELECT * FROM t1 WHERE a=' 1' AND (a XOR '0');
+a
+ 1
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '`1'
+# ' 1' should not be propagated into (a XIR '0')
+EXPLAIN EXTENDED SELECT * FROM t1 WHERE a=' 1' AND (a XOR '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((`test`.`t1`.`a` = ' 1') and (`test`.`t1`.`a` xor '0'))
+DROP TABLE t1;
+#
 # End of 10.1 tests
 #

mysql-test/t/ctype_cp1251.test

@@ -126,6 +126,19 @@ EXPLAIN EXTENDED SELECT * FROM t1 WHERE a IN (1,2,3,'x') AND a=' 1';
 DROP TABLE t1;
 
 
+--echo #
+--echo # MDEV-8671 Wrong result for SELECT..WHERE varchar_column=' 1' AND (varchar_column XOR '1')
+--echo #
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET cp1251 COLLATE cp1251_ukrainian_ci);
+INSERT INTO t1 VALUES (' 1'),('`1');
+SELECT * FROM t1 WHERE a=' 1';
+SELECT * FROM t1 WHERE (a XOR '0');
+SELECT * FROM t1 WHERE a=' 1' AND (a XOR '0');
+--echo # ' 1' should not be propagated into (a XIR '0')
+EXPLAIN EXTENDED SELECT * FROM t1 WHERE a=' 1' AND (a XOR '0');
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.1 tests
 --echo #

sql/item_cmpfunc.h

@@ -442,6 +442,11 @@ public:
     Item_args::propagate_equal_fields(thd, ANY_SUBST, cond);
     return this;
   }
+  void fix_length_and_dec()
+  {
+    Item_bool_func::fix_length_and_dec();
+    args[0]->cmp_context= args[1]->cmp_context= INT_RESULT;
+  }
 };
 
 class Item_func_not :public Item_bool_func