Fix calculation for length of LPAD() and RPAD() reported to

client via mysql_fetch_fields(). (Bug #11311)


mysql-test/r/func_str.result:
  Add new results
mysql-test/t/func_str.test:
  Add new regression test
sql/item_strfunc.cc:
  Fix length reported for LPAD() and RPAD() -- they always truncate to the
  length that is given.

mysql-test/r/func_str.result

@@ -868,3 +868,18 @@ drop table t1;
 select hex(29223372036854775809), hex(-29223372036854775809);
 hex(29223372036854775809)	hex(-29223372036854775809)
 FFFFFFFFFFFFFFFF	FFFFFFFFFFFFFFFF
+create table t1 (i int);
+insert into t1 values (1000000000),(1);
+select lpad(i, 7, ' ') as t from t1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					t	253	7	7	Y	128	31	63
+t
+1000000
+      1
+select rpad(i, 7, ' ') as t from t1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					t	253	7	7	Y	128	31	63
+t
+1000000
+1      
+drop table t1;

mysql-test/t/func_str.test

@@ -611,3 +611,14 @@ drop table t1;
 # Bug #9854  hex() and out of range handling
 #
 select hex(29223372036854775809), hex(-29223372036854775809);
+
+#
+# Bug #11311: Incorrect length returned from LPAD() and RPAD()
+#
+create table t1 (i int);
+insert into t1 values (1000000000),(1);
+--enable_metadata
+select lpad(i, 7, ' ') as t from t1;
+select rpad(i, 7, ' ') as t from t1;
+--disable_metadata
+drop table t1;

sql/item_strfunc.cc

@@ -2042,7 +2042,6 @@ void Item_func_rpad::fix_length_and_dec()
   {
     ulonglong length= ((ulonglong) args[1]->val_int() *
                        collation.collation->mbmaxlen);
-    length= max((ulonglong) args[0]->max_length, length);
     if (length >= MAX_BLOB_WIDTH)
     {
       length= MAX_BLOB_WIDTH;
@@ -2130,7 +2129,6 @@ void Item_func_lpad::fix_length_and_dec()
   {
     ulonglong length= ((ulonglong) args[1]->val_int() *
                        collation.collation->mbmaxlen);
-    length= max((ulonglong) args[0]->max_length, length);
     if (length >= MAX_BLOB_WIDTH)
     {
       length= MAX_BLOB_WIDTH;