Support deep-merging HashWithIndifferentAccess.

[#2732 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

2 files changed, 17 insertions, 4 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/deep_merge.rb b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
index ffde34a741..24d0a2a481 100644
--- a/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
+++ b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
@@ -1,11 +1,12 @@
 class Hash
   # Returns a new hash with +self+ and +other_hash+ merged recursively.
   def deep_merge(other_hash)
-    merge(other_hash) do |key, oldval, newval|
-      oldval = oldval.to_hash if oldval.respond_to?(:to_hash)
-      newval = newval.to_hash if newval.respond_to?(:to_hash)
-      oldval.is_a?( Hash ) && newval.is_a?( Hash ) ? oldval.deep_merge(newval) : newval
+    target = dup
+    other_hash.each_pair do |k,v|
+      tv = target[k]
+      target[k] = tv.is_a?(Hash) && v.is_a?(Hash) ? tv.deep_merge(v) : v
     end
+    target
   end
 
   # Returns a new hash with +self+ and +other_hash+ merged recursively.
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index 8b0f3fc33c..eb4c37aaf0 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -265,6 +265,18 @@ class HashExtTest < Test::Unit::TestCase
     assert_equal expected, hash_1
   end
 
+  def test_deep_merge_on_indifferent_access
+    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 }