Fix & test for the bug #2182: lpad returns incorrect result.

mysql-test/r/func_str.result:
  Test for the bug #2182: lpad returns incorrect result
mysql-test/t/func_str.test:
  Test for the bug #2182: lpad returns incorrect result
sql/item_strfunc.cc:
  Fix for the bug #2182: lpad returns incorrect result

mysql-test/r/func_str.result

@@ -605,3 +605,6 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	select high_priority md5(_latin1'hello') AS `md5('hello')`,sha(_latin1'abc') AS `sha('abc')`,sha(_latin1'abc') AS `sha1('abc')`,soundex(_latin1'') AS `soundex('')`,(soundex(_latin1'mood') = soundex(_latin1'mud')) AS `'mood' sounds like 'mud'`,aes_decrypt(aes_encrypt(_latin1'abc',_latin1'1'),_latin1'1') AS `aes_decrypt(aes_encrypt('abc','1'),'1')`,concat(_latin1'*',repeat(_latin1' ',5),_latin1'*') AS `concat('*',space(5),'*')`,reverse(_latin1'abc') AS `reverse('abc')`,rpad(_latin1'a',4,_latin1'1') AS `rpad('a',4,'1')`,lpad(_latin1'a',4,_latin1'1') AS `lpad('a',4,'1')`,concat_ws(_latin1',',_latin1'',NULL,_latin1'a') AS `concat_ws(',','',NULL,'a')`,make_set(255,_latin2'a',_latin2'b',_latin2'c') AS `make_set(255,_latin2'a',_latin2'b',_latin2'c')`,elt(2,1) AS `elt(2,1)`,locate(_latin1'a',_latin1'b',2) AS `locate("a","b",2)`,format(130,10) AS `format(130,10)`,char(0) AS `char(0)`,conv(130,16,10) AS `conv(130,16,10)`,hex(130) AS `hex(130)`,(_latin1'HE' collate _latin1'BINARY') AS `binary 'HE'`,export_set(255,_latin2'y',_latin2'n',_latin2' ') AS `export_set(255,_latin2'y',_latin2'n',_latin2' ')`,field((_latin1'b' collate _latin1'latin1_bin'),_latin1'A',_latin1'B') AS `FIELD('b' COLLATE latin1_bin,'A','B')`,find_in_set(_latin1'B',_latin1'a,b,c,d') AS `FIND_IN_SET(_latin1'B',_latin1'a,b,c,d')`,collation(conv(130,16,10)) AS `collation(conv(130,16,10))`,coercibility(conv(130,16,10)) AS `coercibility(conv(130,16,10))`,length(_latin1'\n	\r\0\\_\\%\\') AS `length('\n\t\r\b\0\_\%\\')`,bit_length(_latin1'\n	\r\0\\_\\%\\') AS `bit_length('\n\t\r\b\0\_\%\\')`,bit_length(_latin1'\n	\r\0\\_\\%\\') AS `bit_length('\n\t\r\b\0\_\%\\')`,concat(_latin1'monty',_latin1' was here ',_latin1'again') AS `concat('monty',' was here ','again')`,length(_latin1'hello') AS `length('hello')`,char(ascii(_latin1'h')) AS `char(ascii('h'))`,ord(_latin1'h') AS `ord('h')`,quote((1 / 0)) AS `quote(1/0)`,crc32(_latin1'123') AS `crc32("123")`,replace(_latin1'aaaa',_latin1'a',_latin1'b') AS `replace('aaaa','a','b')`,insert(_latin1'txs',2,1,_latin1'hi') AS `insert('txs',2,1,'hi')`,left(_latin2'a',1) AS `left(_latin2'a',1)`,right(_latin2'a',1) AS `right(_latin2'a',1)`,lcase(_latin2'a') AS `lcase(_latin2'a')`,ucase(_latin2'a') AS `ucase(_latin2'a')`,substr(_latin1'abcdefg',3,2) AS `SUBSTR('abcdefg',3,2)`,substr_index(_latin1'1abcd;2abcd;3abcd;4abcd',_latin1';',2) AS `substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2)`,trim(_latin2' a ') AS `trim(_latin2' a ')`,ltrim(_latin2' a ') AS `ltrim(_latin2' a ')`,rtrim(_latin2' a ') AS `rtrim(_latin2' a ')`,decode(encode(repeat(_latin1'a',100000))) AS `decode(encode(repeat("a",100000),"monty"),"monty")`
+SELECT lpad(12345, 5, "#");
+lpad(12345, 5, "#")
+12345

mysql-test/t/func_str.test

@@ -346,3 +346,9 @@ DROP TABLE t1;
 select substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2),substring_index("1abcd;2abcd;3abcd;4abcd", ';', -2);
 
 explain extended select md5('hello'), sha('abc'), sha1('abc'), soundex(''), 'mood' sounds like 'mud', aes_decrypt(aes_encrypt('abc','1'),'1'),concat('*',space(5),'*'), reverse('abc'), rpad('a',4,'1'), lpad('a',4,'1'),  concat_ws(',','',NULL,'a'),make_set(255,_latin2'a',_latin2'b',_latin2'c'),elt(2,1),locate("a","b",2),format(130,10),char(0),conv(130,16,10),hex(130),binary 'HE', export_set(255,_latin2'y',_latin2'n',_latin2' '),FIELD('b' COLLATE latin1_bin,'A','B'),FIND_IN_SET(_latin1'B',_latin1'a,b,c,d'),collation(conv(130,16,10)), coercibility(conv(130,16,10)),length('\n\t\r\b\0\_\%\\'),bit_length('\n\t\r\b\0\_\%\\'),bit_length('\n\t\r\b\0\_\%\\'),concat('monty',' was here ','again'),length('hello'),char(ascii('h')),ord('h'),quote(1/0),crc32("123"),replace('aaaa','a','b'),insert('txs',2,1,'hi'),left(_latin2'a',1),right(_latin2'a',1),lcase(_latin2'a'),ucase(_latin2'a'),SUBSTR('abcdefg',3,2),substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2),trim(_latin2' a '),ltrim(_latin2' a '),rtrim(_latin2' a '), decode(encode(repeat("a",100000),"monty"),"monty");
+
+#
+# Bug #2182
+#
+
+SELECT lpad(12345, 5, "#");

sql/item_strfunc.cc

@@ -2022,9 +2022,8 @@ String *Item_func_lpad::val_str(String *str)
 {
   uint32 res_char_length,pad_char_length;
   ulong count= (long) args[1]->val_int(), byte_count;
-  String a1,a3;
-  String *res= args[0]->val_str(&a1);
-  String *pad= args[2]->val_str(&a3);
+  String *res= args[0]->val_str(&tmp_value);
+  String *pad= args[2]->val_str(&lpad_str);
 
   if (!res || args[1]->null_value || !pad)
     goto err;