Slow memory leak with 1.8.1, rb_yield

Hi all,

I've only tested this so far on Windows XP with VC++ 7.

I noticed that there's a slow memory leak in rb_yield (I think) in
1.8.1.  Here's the sample code:

// foo.c
#include "ruby.h"
#include <windows.h>

static VALUE foo_test(VALUE class){
   rb_yield(rb_str_new2("hello"));
   return Qnil;
}

void Init_foo(){
   VALUE cFoo = rb_define_class("Foo",rb_cObject);
   rb_define_singleton_method(cFoo,"test",foo_test,0);
}
// end foo.c

# extconf.rb
require "mkmf"
create_makefile("foo")
# end extconf.rb

# Sample test script - watch "Mem Usage" in Task Manager while running
$:.unshift Dir.pwd
require "foo"

n = 1
while true
   Foo.test{ |x|
      p x
      puts
   }
   puts "Iteration #{n}"
   n += 1
   sleep 0.5
end

# end test script

This leaks at about 4k per 20 iterations (204b per iteration).  It does
go away if I add an explicit rb_gc() after the rb_yield().

I guess my question is, why do I have to manually garbage collect after
an rb_yield()?  Should this be standard operating procedure?

Regards,

Dan