merges r20866 and r20968 from trunk into ruby_1_9_1.

* error.c (exc_equal): duck typing equal to make it transitive.
  [ruby-dev:34880]
--
* error.c (exc_equal): == method should not raise Exception.
  [ruby-dev:37519]

* sample/test.rb: fix test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21025 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,15 @@
+Wed Dec 24 20:59:12 2008  Koichi Sasada  <ko1@atdot.net>
+
+	* error.c (exc_equal): == method should not raise Exception.
+	  [ruby-dev:37519]
+
+	* sample/test.rb: fix test
+
+Fri Dec 19 07:45:37 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* error.c (exc_equal): duck typing equal to make it transitive.
+	  [ruby-dev:34880]
+
 Wed Dec 24 20:33:45 2008  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_insnhelper.c (vm_call_method): use class of method defined

error.c

@@ -554,15 +554,33 @@ exc_set_backtrace(VALUE exc, VALUE bt)
 static VALUE
 exc_equal(VALUE exc, VALUE obj)
 {
+    VALUE mesg, backtrace;
     ID id_mesg;
 
     if (exc == obj) return Qtrue;
-    if (rb_obj_class(exc) != rb_obj_class(obj))
-	return Qfalse;
     CONST_ID(id_mesg, "mesg");
-    if (!rb_equal(rb_attr_get(exc, id_mesg), rb_attr_get(obj, id_mesg)))
+
+    if (rb_obj_class(exc) != rb_obj_class(obj)) {
+	ID id_message, id_backtrace;
+	CONST_ID(id_message, "message");
+	CONST_ID(id_backtrace, "backtrace");
+
+	if (rb_respond_to(obj, id_message) && rb_respond_to(obj, id_backtrace)) {
+	    mesg = rb_funcall(obj, id_message, 0, 0);
+	    backtrace = rb_funcall(obj, id_backtrace, 0, 0);
+	}
+	else {
+	    return Qfalse;
+	}
+    }
+    else {
+	mesg = rb_attr_get(obj, id_mesg);
+	backtrace = exc_backtrace(obj);
+    }
+
+    if (!rb_equal(rb_attr_get(exc, id_mesg), mesg))
 	return Qfalse;
-    if (!rb_equal(exc_backtrace(exc), exc_backtrace(obj)))
+    if (!rb_equal(exc_backtrace(exc), backtrace))
 	return Qfalse;
     return Qtrue;
 }

sample/test.rb

@@ -660,10 +660,12 @@ begin
     raise $string
   end
   test_ok(false)
-rescue
+rescue => e
-  test_ok(true) if $! == $string
+  test_ok($! == e)
+  test_ok(e.message == $string)
+  test_ok(e != $string)
 end
-  
+
 # exception in ensure clause
 begin
   begin