Allow replace non-conditional non-nesting exposures in child classes (fixes #286) (#292)

Author: DmitryTsepelev

.rubocop_todo.yml

@@ -18,7 +18,7 @@ Metrics/AbcSize:
 # Offense count: 35
 # Configuration parameters: CountComments, ExcludedMethods.
 Metrics/BlockLength:
-  Max: 1489
+  Max: 1496
 
 # Offense count: 2
 # Configuration parameters: CountComments.

CHANGELOG.md

@@ -14,7 +14,8 @@
 #### Fixes
 
 * [#288](https://github.com/ruby-grape/grape-entity/pull/288) Fix wrong argument exception when &:block passed to the expose method  - [@DmitryTsepelev](https://github.com/DmitryTsepelev).
-* [#291](https://github.com/ruby-grape/grape-entity/pull/291) Refactor and simplify various classes and modules
+* [#291](https://github.com/ruby-grape/grape-entity/pull/291) Refactor and simplify various classes and modules  - [@DmitryTsepelev](https://github.com/DmitryTsepelev).
+* [#292](https://github.com/ruby-grape/grape-entity/pull/292): Allow replace non-conditional non-nesting exposures in child classes (fixes  [#286](https://github.com/ruby-grape/grape-entity/issues/286)) - [@DmitryTsepelev](https://github.com/DmitryTsepelev).
 * Your contribution here.
 
 ### 0.6.1 (2017-01-09)

lib/grape_entity/entity.rb

@@ -185,25 +185,24 @@ def self.expose(*args, &block)
 
       @documentation = nil
       @nesting_stack ||= []
+      args.each { |attribute| build_exposure_for_attribute(attribute, @nesting_stack, options, block) }
+    end
 
-      # rubocop:disable Style/Next
-      args.each do |attribute|
-        exposure = Exposure.new(attribute, options)
+    def self.build_exposure_for_attribute(attribute, nesting_stack, options, block)
+      exposure_list = nesting_stack.empty? ? root_exposures : nesting_stack.last.nested_exposures
 
-        if @nesting_stack.empty?
-          root_exposures << exposure
-        else
-          @nesting_stack.last.nested_exposures << exposure
-        end
+      exposure = Exposure.new(attribute, options)
 
-        # Nested exposures are given in a block with no parameters.
-        if exposure.nesting?
-          @nesting_stack << exposure
-          block.call
-          @nesting_stack.pop
-        end
-      end
-      # rubocop:enable Style/Next
+      exposure_list.delete_by(attribute) if exposure_list.select_by(attribute).all? { |exp| exp.replaceable_by?(exposure) }
+
+      exposure_list << exposure
+
+      # Nested exposures are given in a block with no parameters.
+      return unless exposure.nesting?
+
+      nesting_stack << exposure
+      block.call
+      nesting_stack.pop
     end
 
     # Returns exposures that have been declared for this Entity on the top level.

lib/grape_entity/exposure/base.rb

@@ -116,6 +116,10 @@ def with_attr_path(entity, options)
           end
         end
 
+        def replaceable_by?(other)
+          !nesting? && !conditional? && !other.nesting? && !other.conditional?
+        end
+
         protected
 
         attr_reader :options

lib/grape_entity/exposure/nesting_exposure/nested_exposures.rb

@@ -16,6 +16,10 @@ def find_by(attribute)
             @exposures.find { |e| e.attribute == attribute }
           end
 
+          def select_by(attribute)
+            @exposures.select { |e| e.attribute == attribute }
+          end
+
           def <<(exposure)
             reset_memoization!
             @exposures << exposure

spec/grape_entity/entity_spec.rb

@@ -352,6 +352,15 @@ class Parent < Person
           expect(subject.represent({ name: 'bar' }, serializable: true)).to eq(email: nil, name: 'bar')
           expect(child_class.represent({ name: 'bar' }, serializable: true)).to eq(email: nil, name: 'foo')
         end
+
+        it 'overrides parent class exposure' do
+          subject.expose :name
+          child_class = Class.new(subject)
+          child_class.expose :name, as: :child_name
+
+          expect(subject.represent({ name: 'bar' }, serializable: true)).to eq(name: 'bar')
+          expect(child_class.represent({ name: 'bar' }, serializable: true)).to eq(child_name: 'bar')
+        end
       end
 
       context 'register formatters' do