fix for declared(params) inside route_param bug.

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 #### Fixes
 
+* [#1430](https://github.com/ruby-grape/grape/pull/1430): Fix for declared(params) inside route_param. - [@Arkanain](https://github.com/Arkanain).
 * [#1405](https://github.com/ruby-grape/grape/pull/1405): Fix priority of `rescue_from` clauses applying - [@hedgesky](https://github.com/hedgesky).
 * [#1365](https://github.com/ruby-grape/grape/pull/1365): Fix finding exception handler in error middleware - [@ktimothy](https://github.com/ktimothy).
 * [#1380](https://github.com/ruby-grape/grape/pull/1380): Fix `allow_blank: false` for `Time` attributes with valid values causes `NoMethodError` - [@ipkes](https://github.com/ipkes).

lib/grape/validations/params_scope.rb

@@ -190,7 +190,7 @@ def configure_declared_params
           @api.namespace_stackable(:declared_params, @declared_params)
 
           @api.route_setting(:declared_params, []) unless @api.route_setting(:declared_params)
-          @api.route_setting(:declared_params).concat @declared_params
+          @api.route_setting(:declared_params, @api.namespace_stackable(:declared_params).flatten)
         end
       end
 

spec/grape/endpoint_spec.rb

@@ -582,6 +582,79 @@ def app
     end
   end
 
+  describe '#declared; with multiple route_param' do
+    before do
+      mounted = Class.new(Grape::API)
+      mounted.namespace :albums do
+        get do
+          declared(params)
+        end
+      end
+
+      subject.format :json
+      subject.namespace :artists do
+        route_param :id, type: Integer do
+          get do
+            declared(params)
+          end
+
+          params do
+            requires :filter, type: String
+          end
+          get :some_route do
+            declared(params)
+          end
+        end
+
+        route_param :artist_id, type: Integer do
+          namespace :compositions do
+            get do
+              declared(params)
+            end
+          end
+        end
+
+        route_param :compositor_id, type: Integer do
+          mount mounted
+        end
+      end
+    end
+
+    it 'return only :id without :artist_id' do
+      get '/artists/1'
+      json = JSON.parse(last_response.body, symbolize_names: true)
+
+      expect(json.key?(:id)).to be_truthy
+      expect(json.key?(:artist_id)).not_to be_truthy
+    end
+
+    it 'return only :artist_id without :id' do
+      get '/artists/1/compositions'
+      json = JSON.parse(last_response.body, symbolize_names: true)
+
+      expect(json.key?(:artist_id)).to be_truthy
+      expect(json.key?(:id)).not_to be_truthy
+    end
+
+    it 'return :filter and :id parameters in declared for second enpoint inside route_param' do
+      get '/artists/1/some_route', filter: 'some_filter'
+      json = JSON.parse(last_response.body, symbolize_names: true)
+
+      expect(json.key?(:filter)).to be_truthy
+      expect(json.key?(:id)).to be_truthy
+      expect(json.key?(:artist_id)).not_to be_truthy
+    end
+
+    it 'return :compositor_id for mounter in route_param' do
+      get '/artists/1/albums'
+      json = JSON.parse(last_response.body, symbolize_names: true)
+
+      expect(json.key?(:compositor_id)).to be_truthy
+      expect(json.key?(:id)).not_to be_truthy
+      expect(json.key?(:artist_id)).not_to be_truthy
+    end
+  end
+
   describe '#params' do
     it 'is available to the caller' do
       subject.get('/hey') do