From d0868ba96443904cbcee3eb91302c1957647d604 Mon Sep 17 00:00:00 2001
From: Andrew Moreland <andy@andymo.org>
Date: Sat, 8 Aug 2009 20:49:57 -0700
Subject: [PATCH] This commit allows hashes with indifferent access to be deep_merged.

---
 .../core_ext/hash/indifferent_access.rb            |   15 +++++++++++++++
 activesupport/test/core_ext/hash_ext_test.rb       |   12 ++++++++++++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
index 34ba8a0..84e2683 100644
--- a/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
+++ b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
@@ -97,6 +97,21 @@ class HashWithIndifferentAccess < Hash
     super other_hash.with_indifferent_access
   end
 
+  # Performs a deep_merge on a HashWithIndifferentAccess, returning a new HashWithIndifferentAccess with +self+ and +other_hash+ merged recursively.
+  def deep_merge(other_hash)
+    target = dup
+    other_hash.each_pair do |k,v|
+      target[k].is_a?(Hash) && v.is_a?(Hash) ? target[k] = target[k].deep_merge(v) : target[k] = v
+    end
+    target
+  end  
+
+  # Returns a new HashWithIndifferentAccess with +self+ and +other_hash+ merged recursively.
+  # Modifies the receiver in place.
+  def deep_merge!(other_hash)
+    replace(deep_merge(other_hash))
+  end
+
   # Removes a specified key from the hash.
   def delete(key)
     super(convert_key(key))
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index c58c0ac..a0fd40c 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -263,6 +263,18 @@ class HashExtTest < Test::Unit::TestCase
     assert_equal expected, hash_1
   end
 
+  def test_deep_merge_on_indifferent
+    hash_1 = HashWithIndifferentAccess.new({ :a => "a", :b => "b", :c => { :c1 => "c1", :c2 => "c2", :c3 => { :d1 => "d1" } } })
+    hash_2 = HashWithIndifferentAccess.new({ :a => 1, :c => { :c1 => 2, :c3 => { :d2 => "d2" } } })
+    hash_3 = { :a => 1, :c => { :c1 => 2, :c3 => { :d2 => "d2" } } }
+    expected = { "a" => 1, "b" => "b", "c" => { "c1" => 2, "c2" => "c2", "c3" => { "d1" => "d1", "d2" => "d2" } } }
+    assert_equal expected, hash_1.deep_merge(hash_2)
+    assert_equal expected, hash_1.deep_merge(hash_3)
+    hash_1.deep_merge!(hash_2)
+    assert_equal expected, hash_1
+    
+  end
+
   def test_reverse_merge
     defaults = { :a => "x", :b => "y", :c => 10 }.freeze
     options  = { :a => 1, :b => 2 }
-- 
1.6.3.3