From 30aa9703b53c2e70f532d933511c1bd80f208c88 Mon Sep 17 00:00:00 2001
From: Vladimir Kochnev <hashtable@yandex.ru>
Date: Mon, 3 Aug 2015 12:00:32 +0300
Subject: [PATCH] Fixes issue with class reopening and inheriting.

Exposures and formatters should appear in inherited classes even if
added after inheriting.
---
 .rubocop_todo.yml                | 10 +++----
 lib/grape_entity/entity.rb       | 13 +++++++++
 spec/grape_entity/entity_spec.rb | 48 ++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 9d0ce88f..6618152b 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,5 +1,5 @@
 # This configuration was generated by `rubocop --auto-gen-config`
-# on 2015-08-02 19:30:25 +0300 using RuboCop version 0.31.0.
+# on 2015-08-07 13:25:47 +0300 using RuboCop version 0.31.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -7,18 +7,18 @@
 
 # Offense count: 6
 Metrics/AbcSize:
-  Max: 33
+  Max: 36
 
 # Offense count: 2
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 198
+  Max: 208
 
 # Offense count: 3
 Metrics/CyclomaticComplexity:
   Max: 11
 
-# Offense count: 208
+# Offense count: 209
 # Configuration parameters: AllowURI, URISchemes.
 Metrics/LineLength:
   Max: 146
@@ -26,7 +26,7 @@ Metrics/LineLength:
 # Offense count: 8
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
-  Max: 28
+  Max: 31
 
 # Offense count: 5
 Metrics/PerceivedComplexity:
diff --git a/lib/grape_entity/entity.rb b/lib/grape_entity/entity.rb
index e455323d..08c2eb08 100644
--- a/lib/grape_entity/entity.rb
+++ b/lib/grape_entity/entity.rb
@@ -103,11 +103,16 @@ class << self
       # Returns all formatters that are registered for this and it's ancestors
       # @return [Hash] of formatters
       attr_accessor :formatters
+      attr_accessor :inherited_entities
     end
 
+    @inherited_entities = []
+
     def self.inherited(subclass)
       subclass.root_exposure = root_exposure.try(:dup) || build_root_exposure
       subclass.formatters = formatters.try(:dup) || {}
+      inherited_entities << subclass
+      subclass.inherited_entities = []
     end
 
     # This method is the primary means by which you will declare what attributes
@@ -173,6 +178,10 @@ def self.expose(*args, &block)
           @nesting_stack.pop
         end
       end
+
+      inherited_entities.each do |entity|
+        entity.expose(*args, &block)
+      end
     end
 
     def self.build_root_exposure
@@ -264,6 +273,10 @@ def self.documentation
     def self.format_with(name, &block)
       fail ArgumentError, 'You must pass a block for formatters' unless block_given?
       formatters[name.to_sym] = block
+
+      inherited_entities.each do |entity|
+        entity.format_with(name, &block)
+      end
     end
 
     # This allows you to set a root element name for your representation.
diff --git a/spec/grape_entity/entity_spec.rb b/spec/grape_entity/entity_spec.rb
index 62a95ef5..292fb9ff 100644
--- a/spec/grape_entity/entity_spec.rb
+++ b/spec/grape_entity/entity_spec.rb
@@ -272,6 +272,47 @@ 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
+
+        describe 'parent class reopening' do
+          it 'is supported' do
+            subject.expose :name
+            child_class = Class.new(subject)
+            subject.expose :email
+
+            object = OpenStruct.new(name: 'bar', email: 'foo@bar')
+            expected = { name: 'bar', email: 'foo@bar' }
+
+            expect(subject.represent(object, serializable: true)).to eq(expected)
+            expect(child_class.represent(object, serializable: true)).to eq(expected)
+          end
+
+          it 'puts exposures in the right order' do
+            subject.expose :x
+            child_class = Class.new(subject) do
+              expose :z
+            end
+            subject.expose :y
+            object = {
+              x: 1,
+              y: 2,
+              z: 3
+            }
+            expect(child_class.represent(object, serializable: true).keys).to eq([:x, :y, :z])
+          end
+
+          it 'just prepends parent class exposures to the inherited class' do
+            subject.expose :x
+            child_class = Class.new(subject) do
+              expose :y, proc: -> (_obj, _opts) { 'specific' }
+            end
+            subject.expose :y
+            object = {
+              x: 1,
+              y: 2
+            }
+            expect(child_class.represent(object, serializable: true)).to eq(x: 1, y: 'specific')
+          end
+        end
       end
 
       context 'register formatters' do
@@ -290,6 +331,13 @@ class Parent < Person
           expect(child_class.formatters).to eq subject.formatters
         end
 
+        it 'inherits formatters from ancestors with reopening' do
+          child_class = Class.new(subject)
+          subject.format_with :timestamp, &date_formatter
+
+          expect(child_class.formatters).to eq subject.formatters
+        end
+
         it 'does not allow registering a formatter without a block' do
           expect { subject.format_with :foo }.to raise_error ArgumentError
         end