Skip to set default value unless meets_dependency? (#2097)

CHANGELOG.md

@@ -11,6 +11,7 @@
 * [#2083](https://github.com/ruby-grape/grape/pull/2083): Set `Cache-Control` header only for streamed responses - [@stanhu](https://github.com/stanhu).
 * [#2092](https://github.com/ruby-grape/grape/pull/2092): Correct an example params in Include Missing doc - [@huyvohcmc](https://github.com/huyvohcmc).
 * [#2091](https://github.com/ruby-grape/grape/pull/2091): Fix ruby 2.7 keyword deprecations - [@dim](https://github.com/dim).
+* [#2097](https://github.com/ruby-grape/grape/pull/2097): Skip to set default value unless `meets_dependency?` - [@wanabe](https://github.com/wanabe).
 
 ### 1.4.0 (2020/07/10)
 

lib/grape/validations/validators/default.rb

@@ -21,6 +21,7 @@ def validate_param!(attr_name, params)
       def validate!(params)
         attrs = SingleAttributeIterator.new(self, @scope, params)
         attrs.each do |resource_params, attr_name|
+          next unless @scope.meets_dependency?(resource_params, params)
           validate_param!(attr_name, resource_params) if resource_params.is_a?(Hash) && resource_params[attr_name].nil?
         end
       end

spec/grape/validations/validators/default_spec.rb

@@ -419,4 +419,53 @@ def app
       end
     end
   end
+
+  context 'array with default values and given conditions' do
+    subject do
+      Class.new(Grape::API) do
+        default_format :json
+      end
+    end
+
+    def app
+      subject
+    end
+
+    it 'applies the default values only if the conditions are met' do
+      subject.params do
+        requires :ary, type: Array do
+          requires :has_value, type: Grape::API::Boolean
+          given has_value: ->(has_value) { has_value } do
+            optional :type, type: String, values: %w[str int], default: 'str'
+            given type: ->(type) { type == 'str' } do
+              optional :str, type: String, default: 'a'
+            end
+            given type: ->(type) { type == 'int' } do
+              optional :int, type: Integer, default: 1
+            end
+          end
+        end
+      end
+      subject.post('/nested_given_and_default') { declared(self.params) }
+
+      params = {
+        ary: [
+          { has_value: false },
+          { has_value: true, type: 'int', int: 123 },
+          { has_value: true, type: 'str', str: 'b' }
+        ]
+      }
+      expected = {
+        'ary' => [
+          { 'has_value' => false, 'type' => nil,   'int' => nil, 'str' => nil },
+          { 'has_value' => true,  'type' => 'int', 'int' => 123, 'str' => nil },
+          { 'has_value' => true,  'type' => 'str', 'int' => nil, 'str' => 'b' }
+        ]
+      }
+
+      post '/nested_given_and_default', params
+      expect(last_response.status).to eq(201)
+      expect(JSON.parse(last_response.body)).to eq(expected)
+    end
+  end
 end