* hash.c (initialize_copy): duping should rehash the hash.

* test/ruby/test_hash.rb: added a test to ensure rehash.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37248 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Thu Oct 18 09:23:03 2012  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* hash.c (initialize_copy): duping should rehash the hash.
+
+	* test/ruby/test_hash.rb: added a test to ensure rehash.
+
 Wed Oct 17 21:16:47 2012  Hiroshi Shirosaki  <h.shirosaki@gmail.com>
 
 	* common.mk (WPROGRAM): need same dependencies as PROGRAM.

hash.c

@@ -1187,8 +1187,11 @@ rb_hash_initialize_copy(VALUE hash, VALUE hash2)
 {
     Check_Type(hash2, T_HASH);
 
-    if (!RHASH_EMPTY_P(hash2))
+    if (!RHASH_EMPTY_P(hash2)) {
         RHASH(hash)->ntbl = st_copy(RHASH(hash2)->ntbl);
+	rb_hash_rehash(hash);
+    }
+
     if (FL_TEST(hash2, HASH_PROC_DEFAULT)) {
         FL_SET(hash, HASH_PROC_DEFAULT);
     }

test/ruby/test_hash.rb

@@ -100,6 +100,15 @@ class TestHash < Test::Unit::TestCase
     assert_raises(TypeError) { h.dup }
   end
 
+  def test_dup_will_rehash
+    set1 = { }
+    set2 = { set1 => true}
+
+    set1[set1] = true
+
+    assert_equal set2, set2.dup
+  end
+
   def test_s_AREF
     h = @cls["a" => 100, "b" => 200]
     assert_equal(100, h['a'])