Make reverse_merge compatible with subclassing.

4 files changed, 22 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c2464b4..205202e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 * [#317](https://github.com/intridea/hashie/pull/317): Ensure `Hashie::Extensions::MethodQuery` methods return boolean values - [@michaelherold](https://github.com/michaelherold).
 * [#319](https://github.com/intridea/hashie/pull/319): Fix a regression from 3.4.1 where `Hashie::Extensions::DeepFind` is no longer indifference-aware - [@michaelherold](https://github.com/michaelherold).
 * [#240](https://github.com/intridea/hashie/pull/240): Fixed nesting twice with Clash keys - [@bartoszkopinski](https://github.com/bartoszkopinski).
+* [#322](https://github.com/intridea/hashie/pull/322): Fixed `reverse_merge` issue with `Mash` subclasses - [@marshall-lee](https://github.com/marshall-lee).
 * Your contribution here.
 
 ## 3.4.3 (10/25/2015)
diff --git a/UPGRADING.md b/UPGRADING.md
index f9ab157..5645686 100644
--- a/UPGRADING.md
+++ b/UPGRADING.md
@@ -1,6 +1,17 @@
 Upgrading Hashie
 ================
 
+### Upgrading to 3.4.4
+
+#### Mash subclasses and reverse_merge
+
+```ruby
+class MyMash < Hashie::Mash
+end
+```
+
+In versions >= 3.4.4 `MyMash#reverse_merge` returns an instance of `MyMash` but in previous versions it was a `Hashie::Mash` instance.
+
 ### Upgrading to 3.2.2
 
 #### Testing if key defined
diff --git a/lib/hashie/mash.rb b/lib/hashie/mash.rb
index 8bd040f..8dff97e 100644
--- a/lib/hashie/mash.rb
+++ b/lib/hashie/mash.rb
@@ -247,7 +247,7 @@ module Hashie
 
     # another ActiveSupport method, see issue #270
     def reverse_merge(other_hash)
-      Hashie::Mash.new(other_hash).merge(self)
+      self.class.new(other_hash).merge(self)
     end
 
     protected
diff --git a/spec/hashie/mash_spec.rb b/spec/hashie/mash_spec.rb
index ea3d089..c142048 100644
--- a/spec/hashie/mash_spec.rb
+++ b/spec/hashie/mash_spec.rb
@@ -676,5 +676,14 @@ describe Hashie::Mash do
     it 'does not overwrite values' do
       expect(subject.reverse_merge(a: 5).a).to eq subject.a
     end
+
+    context 'when using with subclass' do
+      let(:subclass) { Class.new(Hashie::Mash) }
+      subject { subclass.new(a: 1) }
+
+      it 'creates an instance of subclass' do
+        expect(subject.reverse_merge(a: 5)).to be_kind_of(subclass)
+      end
+    end
   end
 end