From: Ryan Davis <ryand-ruby@...>
Date: 2004-04-16T13:09:08+09:00
Subject: Possible bug in init_copy or rb_gc_copy_finalizer?

The following code:

	#!/usr/bin/ruby -w

	obj = Object.new
	ObjectSpace.define_finalizer(obj) { |an_id| puts "finalizing #{an_id}" 
}
	obj2 = obj.clone

causes the following output:

	./blah.rb:5: warning: copy_finalizer: descarding old finalizers
	finalizing 935212
	finalizing 935242

Eric and I think this is the correct patch:

<517> cvs diff -du object.c gc.c
Index: object.c
===================================================================
RCS file: /src/ruby/object.c,v
retrieving revision 1.134.2.8
diff -d -u -r1.134.2.8 object.c
--- object.c    14 Apr 2004 04:06:52 -0000      1.134.2.8
+++ object.c    16 Apr 2004 04:03:46 -0000
@@ -263,7 +263,7 @@
      }
      clone = rb_obj_alloc(rb_obj_class(obj));
      RBASIC(clone)->klass = rb_singleton_class_clone(obj);
-    RBASIC(clone)->flags = (RBASIC(obj)->flags | FL_TEST(clone, 
FL_TAINT)) & ~FL_FREEZE;
+    RBASIC(clone)->flags = (RBASIC(obj)->flags | FL_TEST(clone, 
FL_TAINT)) & ~(FL_FREEZE|FL_FINALIZE);
      init_copy(clone, obj);
      RBASIC(clone)->flags |= RBASIC(obj)->flags & FL_FREEZE;

Index: gc.c
===================================================================
RCS file: /src/ruby/gc.c,v
retrieving revision 1.168.2.1
diff -d -u -r1.168.2.1 gc.c
--- gc.c        12 Apr 2004 10:11:34 -0000      1.168.2.1
+++ gc.c        16 Apr 2004 04:03:47 -0000
@@ -1719,12 +1719,10 @@

      if (!finalizer_table) return;
      if (!FL_TEST(obj, FL_FINALIZE)) return;
-    if (FL_TEST(dest, FL_FINALIZE)) {
-       rb_warn("copy_finalizer: discarding old finalizers");
-    }
      if (st_lookup(finalizer_table, obj, &table)) {
         st_insert(finalizer_table, dest, table);
      }
+    RBASIC(dest)->flags |= FL_FINALIZE;
  }

  static VALUE

-----

1) We added FL_FINALIZE to the flags to strip from the cloned object,

2) We think that the removed FL_TEST isn't necessary because 
rb_gc_copy_finalizer is only called from init_copy so far and we have 
stripped FL_FINALIZE from the flags just before calling init_copy.

3) We set the finalize flag on the cloned object after we insert the 
cloned object into the finalizer_table.

Please let us know if this is sufficient.

Thank you