From: matz@... (Yukihiro Matsumoto)
Date: 1999-08-10T00:26:37+09:00
Subject: [ruby-talk:00594] Re: Bug in Array#clone!


In message "[ruby-talk:00590] Bug in Array#clone!"
    on 99/08/09, clemens.hintze@alcatel.de <clemens.hintze@alcatel.de> writes:

|and here the next problem... :-)

Well, thank .. you.

|A short analyze of array.c let me believe, that `Array#clone' is wrong.
|It seems only to clone the own (hidden) memory, but forget all about
|possible instance variables.

You are right. I modified CLONESETUP() to copy instance variables.

|As I have seen, the datatype `RArray' has no `iv_table' pointer. But as
|the example shows, instance variables could be stored too. But how?

It is done by one big hash table of hashes.  See variable.c around
*_generic_ivar() functions.

--- /tmp/ruby.h	Tue Aug 10 00:21:16 1999
+++ ruby.h	Mon Aug  9 23:52:35 1999
@@ -211,6 +211,7 @@
 }
-#define CLONESETUP(clone,obj) {\
+#define CLONESETUP(clone,obj) do {\
     OBJSETUP(clone,rb_singleton_class_clone(RBASIC(obj)->klass),RBASIC(obj)->flags);\
     rb_singleton_class_attached(RBASIC(clone)->klass, (VALUE)clone);\
-}
+    if (FL_TEST(obj, FL_EXIVAR)) rb_clone_generic_ivar(clone,obj);\
+} while (0)
 
--- /tmp/variable.c	Tue Aug 10 00:21:27 1999
+++ variable.c	Tue Aug 10 00:03:34 1999
@@ -788,2 +788,3 @@
 
+    if (!generic_iv_tbl) return;
     if (st_lookup(generic_iv_tbl, obj, &tbl)) {
@@ -807,4 +808,4 @@
 {
-    if (special_generic_ivar == 0) return;
     if (!generic_iv_tbl) return;
+    if (special_generic_ivar == 0) return;
     st_foreach(generic_iv_tbl, givar_i, 0);
@@ -820,2 +821,14 @@
 	st_free_table(tbl);
+}
+
+void
+rb_clone_generic_ivar(clone, obj)
+    VALUE clone, obj;
+{
+    st_table *tbl;
+
+    if (!generic_iv_tbl) return;
+    if (st_lookup(generic_iv_tbl, obj, &tbl)) {
+	st_add_direct(generic_iv_tbl, clone, st_copy(tbl));
+    }
 }