ensure complete declared params structure is present

lib/grape/dsl/inside_route.rb

@@ -99,12 +99,14 @@ def declared_param_is_array?(params_nested_path)
         end
 
         def should_be_empty_hash?(passed_children_params, params_nested_path)
-          passed_children_params.empty? && declared_param_is_hash?(params_nested_path)
+          passed_children_params.empty? && declared_param_is_empty_hash?(params_nested_path)
         end
 
-        def declared_param_is_hash?(params_nested_path)
+        def declared_param_is_empty_hash?(params_nested_path)
           key = route_options_params_key(params_nested_path)
-          route_options_params[key] && route_options_params[key][:type] == 'Hash'
+          has_children = route_options_params.keys.any? { |k| k != key && k.start_with?(key) }
+
+          route_options_params[key] && route_options_params[key][:type] == 'Hash' && !has_children
         end
 
         def route_options_params

spec/grape/endpoint_spec.rb

@@ -393,7 +393,11 @@ def app
 
       get '/declared?first=present&nested[fourth]=1'
       expect(last_response.status).to eq(200)
-      expect(JSON.parse(last_response.body)['nested'].keys.size).to eq 4
+
+      body = JSON.parse(last_response.body)
+      expect(body['nested'].keys).to eq(%w[fourth fifth nested_two nested_arr])
+      expect(body['nested']['nested_two'].keys).to eq(%w[sixth nested_three])
+      expect(body['nested']['nested_two']['nested_three'].keys).to eq(%w[seventh])
     end
 
     it 'builds nested params when given array' do
@@ -424,7 +428,7 @@ def app
 
         get '/declared?first=present'
         expect(last_response.status).to eq(200)
-        expect(JSON.parse(last_response.body)['nested']).to eq({})
+        expect(JSON.parse(last_response.body)['nested']).to be_a(Hash)
       end
 
       it 'to be an array when include_missing is true' do