Index: lib/ostruct.rb
===================================================================
--- lib/ostruct.rb	(revision 21202)
+++ lib/ostruct.rb	(working copy)
@@ -112,25 +112,23 @@
   def inspect
     str = "#<#{self.class}"
 
-    Thread.current[InspectKey] ||= []
-    if Thread.current[InspectKey].include?(self) then
-      str << " ..."
-    else
+    ids = (Thread.current[InspectKey] ||= [])
+    if ids.include?(object_id)
+      return str << ' ...>'
+    end
+
+    ids << object_id
+    begin
       first = true
       for k,v in @table
         str << "," unless first
         first = false
-
-        Thread.current[InspectKey] << v
-        begin
-          str << " #{k}=#{v.inspect}"
-        ensure
-          Thread.current[InspectKey].pop
-        end
+        str << " #{k}=#{v.inspect}"
       end
+      return str << '>'
+    ensure
+      ids.pop
     end
-
-    str << ">"
   end
   alias :to_s :inspect
 
Index: test/ostruct/test_ostruct.rb
===================================================================
--- test/ostruct/test_ostruct.rb	(revision 21202)
+++ test/ostruct/test_ostruct.rb	(working copy)
@@ -20,4 +20,12 @@
     o2.instance_eval{@table = {:a => 'b'}}
     assert_not_equal(o1, o2)
   end
+  
+  def test_inspect
+    foo = OpenStruct.new
+    foo.bar = OpenStruct.new
+    assert_equal('#<OpenStruct bar=#<OpenStruct>>', foo.inspect)
+    foo.bar.foo = foo
+    assert_equal('#<OpenStruct bar=#<OpenStruct foo=#<OpenStruct ...>>>', foo.inspect)
+  end
 end