Nice logic for deep_dup in rails

activesupport/lib/active_support/core_ext/array.rb

 require 'active_support/core_ext/array/wrap'
 require 'active_support/core_ext/array/access'
 require 'active_support/core_ext/array/uniq_by'
+require 'active_support/core_ext/array/deep_dup'
 require 'active_support/core_ext/array/conversions'
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/array/grouping'

activesupport/lib/active_support/core_ext/array/deep_dup.rb

+class Array
+  # Returns a deep copy of array.
+  def deep_dup
+    map { |it| it.deep_dup }
+  end
+end

activesupport/lib/active_support/core_ext/hash/deep_dup.rb

 class Hash
   # Returns a deep copy of hash.
   def deep_dup
-    duplicate = self.dup
-    duplicate.each_pair do |k,v|
-      duplicate[k] = v.is_a?(Hash) ? v.deep_dup : v
+    each_with_object(dup) do |(key, value), hash|
+      hash[key.deep_dup] = value.deep_dup
     end
-    duplicate
   end
 end

activesupport/lib/active_support/core_ext/object.rb

 require 'active_support/core_ext/object/acts_like'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/object/duplicable'
+require 'active_support/core_ext/object/deep_dup'
 require 'active_support/core_ext/object/try'
 require 'active_support/core_ext/object/inclusion'
 

activesupport/lib/active_support/core_ext/object/deep_dup.rb

+class Object
+  # Returns a deep copy of object if it's duplicable.
+  def deep_dup
+    duplicable? ? dup : self
+  end
+end

activesupport/test/core_ext/deep_dup_test.rb

+require 'active_support/core_ext/object'
+require 'active_support/core_ext/array'
+require 'active_support/core_ext/hash'
+
+class DeepDupTest < ActiveSupport::TestCase
+
+  def test_array_deep_dup
+    array = [1, [2, 3]]
+    dup = array.deep_dup
+    dup[1][2] = 4
+    assert_equal nil, array[1][2]
+    assert_equal 4, dup[1][2]
+  end
+
+  def test_hash_deep_dup
+    hash = { :a => { :b => 'b' } }
+    dup = hash.deep_dup
+    dup[:a][:c] = 'c'
+    assert_equal nil, hash[:a][:c]
+    assert_equal 'c', dup[:a][:c]
+  end
+
+  def test_array_deep_dup_with_hash_inside
+    array = [1, { :a => 2, :b => 3 } ]
+    dup = array.deep_dup
+    dup[1][:c] = 4
+    assert_equal nil, array[1][:c]
+    assert_equal 4, dup[1][:c]
+  end
+
+  def test_hash_deep_dup_with_array_inside
+    hash = { :a => [1, 2] }
+    dup = hash.deep_dup
+    dup[:a][2] = 'c'
+    assert_equal nil, hash[:a][2]
+    assert_equal 'c', dup[:a][2]
+  end
+
+  def test_deep_dup_initialize
+    zero_hash = Hash.new 0
+    hash = { :a => zero_hash }
+    dup = hash.deep_dup
+    assert_equal 0, dup[:a][44]
+  end
+
+  def test_object_deep_dup
+    object = Object.new
+    dup = object.deep_dup
+    dup.instance_variable_set(:@a, 1)
+    assert !object.instance_variable_defined?(:@a)
+    assert dup.instance_variable_defined?(:@a)
+  end
+
+end

activesupport/test/core_ext/hash_ext_test.rb

@@ -363,21 +363,6 @@ def test_deep_merge_on_indifferent_access
     assert_equal expected, hash_1
   end
 
-  def test_deep_dup
-    hash = { :a => { :b => 'b' } }
-    dup = hash.deep_dup
-    dup[:a][:c] = 'c'
-    assert_equal nil, hash[:a][:c]
-    assert_equal 'c', dup[:a][:c]
-  end
-
-  def test_deep_dup_initialize
-    zero_hash = Hash.new 0
-    hash = { :a => zero_hash }
-    dup = hash.deep_dup
-    assert_equal 0, dup[:a][44]
-  end
-
   def test_store_on_indifferent_access
     hash = HashWithIndifferentAccess.new
     hash.store(:test1, 1)

railties/lib/rails/configuration.rb

 require 'active_support/deprecation'
 require 'active_support/ordered_options'
+require 'active_support/core_ext/object'
 require 'active_support/core_ext/hash/deep_dup'
+require 'active_support/core_ext/array/deep_dup'
 require 'rails/paths'
 require 'rails/rack'