MONGOID-4357 Fix merging selector with objects not responding to |

lib/origin/selector.rb

@@ -19,7 +19,13 @@ def merge!(other)
       other.each_pair do |key, value|
         if value.is_a?(Hash) && self[key.to_s].is_a?(Hash)
           value = self[key.to_s].merge(value) do |_key, old_val, new_val|
-            _key == '$in' ? new_val & old_val : old_val | new_val
+            if in?(_key)
+              new_val & old_val
+            elsif nin?(_key)
+              (old_val + new_val).uniq
+            else
+              new_val
+            end
           end
         end
         if multi_selection?(key)
@@ -188,5 +194,15 @@ def multi_selection?(key)
     def multi_value?(key)
       key =~ /\$nin|\$in/
     end
+
+    private
+
+    def in?(key)
+      key =~ /\$in/
+    end
+
+    def nin?(key)
+      key =~ /\$nin/
+    end
   end
 end

spec/origin/selector_spec.rb

@@ -135,6 +135,27 @@
       end
     end
 
+    context 'when an object does not support the | operator' do
+
+      before do
+        selector['start'] = selection
+        selector.merge!(other)
+      end
+
+      let(:selection) do
+        { '$lt' => Time.now }
+      end
+
+      let(:other) do
+        { 'start' => selection, 'name' => 'test',  }
+      end
+
+      it "merges" do
+        expect(selector['name']).to eq('test')
+        expect(selector['start']).to eq(selection)
+      end
+    end
+
     context "when the selector contains an $or" do
 
       let(:initial) do