diff --git a/ChangeLog b/ChangeLog
index 4feac82280..3d68349b14 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Fri Jul 17 01:22:57 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* array.c (recursive_join): raise ArgumentError for joining
+	  recursive array.
+
+	* array.c (ary_join_1): ditto.
+
+	* test/ruby/test_array.rb (TestArray#test_join2): test updated for
+	  recursive join.
+
 Thu Jul 16 23:32:16 2009  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 
 	* ext/tk/extconf.rb,ext/tk/config_list.in: ignore paths which includes
diff --git a/array.c b/array.c
index b9b60c8736..d8f787c029 100644
--- a/array.c
+++ b/array.c
@@ -1530,7 +1530,7 @@ recursive_join(VALUE obj, VALUE argp, int recur)
     VALUE result = arg[2];
 
     if (recur) {
-	rb_str_buf_cat_ascii(result, "[...]");
+	rb_raise(rb_eArgError, "recursive array join");
     }
     else {
 	ary_join_1(obj, ary, sep, 0, result);
@@ -1573,8 +1573,7 @@ ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result)
 	    obj = val;
 	  ary_join:
 	    if (val == ary) {
-		val = rb_usascii_str_new2("[...]");
-		goto str_join;
+		rb_raise(rb_eArgError, "recursive array join");
 	    }
 	    else {
 		VALUE args[3];
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index c51e179a5f..489b401574 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1490,12 +1490,12 @@ class TestArray < Test::Unit::TestCase
   def test_join2
     a = []
     a << a
-    assert_equal("[...]", a.join)
+    assert_raise(ArgumentError){a.join}
 
     def (a = Object.new).to_a
       [self]
     end
-    assert_equal("[...]", [a].join, '[ruby-core:24150]')
+    assert_raise(ArgumentError, '[ruby-core:24150]'){[a].join}
     assert_equal("12345", [1,[2,[3,4],5]].join)
   end