A fix (bug #5498 TRIM fails with LEADING or TRAILING if remstr = str).

mysql-test/r/func_str.result

@@ -282,3 +282,9 @@ NULL	NULL	1	1	n
 two	'two'	0	0	'two'
 four	'four'	0	0	'four'
 drop table t1;
+select trim(trailing 'foo' from 'foo');
+trim(trailing 'foo' from 'foo')
+
+select trim(leading 'foo' from 'foo');
+trim(leading 'foo' from 'foo')
+

mysql-test/t/func_str.test

@@ -172,3 +172,10 @@ create table t1(a char(4));
 insert into t1 values ('one'),(NULL),('two'),('four');
 select a, quote(a), isnull(quote(a)), quote(a) is null, ifnull(quote(a), 'n') from t1;
 drop table t1;
+
+#
+# Bug #5498: TRIM fails with LEADING or TRAILING if remstr = str
+#
+
+select trim(trailing 'foo' from 'foo');
+select trim(leading 'foo' from 'foo');

sql/item_strfunc.cc

@@ -1135,7 +1135,7 @@ String *Item_func_ltrim::val_str(String *str)
   {
     const char *r_ptr=remove_str->ptr();
     end-=remove_length;
-    while (ptr < end && !memcmp(ptr,r_ptr,remove_length))
+    while (ptr <= end && !memcmp(ptr, r_ptr, remove_length))
       ptr+=remove_length;
     end+=remove_length;
   }
@@ -1206,8 +1206,8 @@ String *Item_func_rtrim::val_str(String *str)
     else
 #endif /* USE_MB */
     {
-      while (ptr + remove_length < end &&
-	     !memcmp(end-remove_length,r_ptr,remove_length))
+      while (ptr + remove_length <= end &&
+	     !memcmp(end-remove_length, r_ptr, remove_length))
 	end-=remove_length;
     }
   }