Attributes with nil values should not be considered "missing".

CHANGELOG.md

@@ -1,7 +1,7 @@
 Next Release
 ============
 
-* Your contribution here.
+* [#864](https://github.com/intridea/grape/pull/864): Attributes with nil values should not be considered "missing"Your contribution here. - [@ppadron](https://github.com/ppadron).
 
 0.10.0 (12/19/2014)
 ===================

README.md

@@ -638,6 +638,29 @@ curl -X POST -H "Content-Type: application/json" localhost:9292/users/signup -d
 }
 ````
 
+Note that an attribute with a `nil` value is not considered *missing* and will also be returned
+when `include_missing` is set to `false`:
+
+**Request**
+
+````bash
+curl -X POST -H "Content-Type: application/json" localhost:9292/users/signup -d '{"user": {"first_name":"first name", "last_name": null, "address": { "city": "SF"}}}'
+````
+
+**Response with include_missing:false**
+
+````json
+{
+  "declared_params": {
+    "user": {
+      "first_name": "first name",
+      "last_name": null,
+      "address": { "city": "SF"}
+    }
+  }
+}
+````
+
 ## Parameter Validation and Coercion
 
 You can define validations and coercion options for your parameters using a `params` block.

UPGRADING.md

@@ -1,6 +1,12 @@
 Upgrading Grape
 ===============
 
+### Upgrading to Next Release
+
+#### Changes to `include_missing`
+
+Attributes with `nil` values or with valus that evaluate to `false` are no longer considered *missing* and will be returned when `include_missing` is `false`.
+
 ### Upgrading to >= 0.10.0
 
 #### Changes to content-types

lib/grape/dsl/inside_route.rb

@@ -38,7 +38,7 @@ def declared(params, options = {}, declared_params = nil)
             key.each_pair do |parent, children|
               output_key = options[:stringify] ? parent.to_s : parent.to_sym
 
-              next unless options[:include_missing] || children || params[parent]
+              next unless options[:include_missing] || children || params.key?(parent)
 
               if params.key?(parent) || options[:include_missing]
                 hash[output_key] = if children

spec/grape/endpoint_spec.rb

@@ -328,6 +328,38 @@ def app
       expect(last_response.status).to eq(200)
     end
 
+    it 'should not consider as a missing attribute a value that evaluates to false' do
+      subject.params do
+        requires :first
+        optional :boolean
+      end
+
+      subject.post '/declared' do
+        error!('expected false', 400) if declared(params, include_missing: false)[:boolean] != false
+        ''
+      end
+
+      post '/declared', MultiJson.dump(first: 'one', boolean: false), 'CONTENT_TYPE' => 'application/json'
+      expect(last_response.status).to eq(201)
+    end
+
+    it 'should not consider `nil` as a missing attribute' do
+      subject.params do
+        requires :first
+        optional :second
+      end
+
+      subject.post '/declared' do
+        unless declared(params, include_missing: false)[:second].nil?
+          error!('expected nil', 400)
+        end
+        ''
+      end
+
+      post '/declared', MultiJson.dump(first: 'one', second: nil), 'CONTENT_TYPE' => 'application/json'
+      expect(last_response.status).to eq(201)
+    end
+
     it 'does not include missing attributes when there are nested hashes' do
       subject.get '/dummy' do
       end
@@ -356,9 +388,9 @@ def app
 
       expect(last_response.status).to eq(200)
       expect(inner_params[:first]).to eq 'present'
-      expect(inner_params[:nested].keys).to eq [:fourth, :nested_nested]
+      expect(inner_params[:nested].keys).to eq [:fourth, :fifth, :nested_nested]
       expect(inner_params[:nested][:fourth]).to eq ''
-      expect(inner_params[:nested][:nested_nested].keys).to eq [:sixth]
+      expect(inner_params[:nested][:nested_nested].keys).to eq [:sixth, :seven]
       expect(inner_params[:nested][:nested_nested][:sixth]).to eq 'sixth'
     end
   end