Bug #2959 UTF8 charset breaks joins with mixed column/string constant

mysql-test/r/ctype_utf8.result

@@ -169,3 +169,28 @@ hex(s1)
 drop table t1;
 create table t1 (a text character set utf8, primary key(a(360)));
 ERROR 42000: Specified key was too long; max key length is 1000 bytes
+CREATE TABLE t1 ( a varchar(10) ) CHARACTER SET utf8;
+INSERT INTO t1 VALUES ( 'test' );
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = b.a;
+a	a
+test	test
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = 'test' and b.a = 'test';
+a	a
+test	test
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = b.a and a.a = 'test';
+a	a
+test	test
+DROP TABLE t1;
+create table t1 (a char(255) character set utf8);
+insert into t1 values('b'),('b');
+select * from t1 where a = 'b';
+a
+b
+b
+select * from t1 where a = 'b' and a = 'b';
+a
+b
+b
+select * from t1 where a = 'b' and a != 'b';
+a
+drop table t1;

mysql-test/t/ctype_utf8.test

@@ -105,3 +105,22 @@ drop table t1;
 #
 --error 1071
 create table t1 (a text character set utf8, primary key(a(360)));
+
+
+#
+# Bug 2959
+# UTF8 charset breaks joins with mixed column/string constant
+#
+CREATE TABLE t1 ( a varchar(10) ) CHARACTER SET utf8;
+INSERT INTO t1 VALUES ( 'test' );
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = b.a;
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = 'test' and b.a = 'test';
+SELECT a.a, b.a FROM t1 a, t1 b WHERE a.a = b.a and a.a = 'test';
+DROP TABLE t1;
+
+create table t1 (a char(255) character set utf8);
+insert into t1 values('b'),('b');
+select * from t1 where a = 'b';
+select * from t1 where a = 'b' and a = 'b';
+select * from t1 where a = 'b' and a != 'b';
+drop table t1;

sql/item.h

@@ -533,7 +533,8 @@ public:
   bool eq(const Item *item, bool binary_cmp) const;
   Item *new_item() 
   {
-    return new Item_string(name, str_value.ptr(), max_length, &my_charset_bin);
+    return new Item_string(name, str_value.ptr(), 
+    			   str_value.length(), &my_charset_bin);
   }
   String *const_string() { return &str_value; }
   inline void append(char *str, uint length) { str_value.append(str, length); }