From 7ae0af3949cf76b6f7c858eff3311d35526f128b Mon Sep 17 00:00:00 2001
From: "J.W. Koelewijn" <jwkoelewijn@gmail.com>
Date: Thu, 26 Jan 2012 12:24:11 +0100
Subject: [PATCH] Updated relationship initialization to be able to support
 more complex resource model creation in which the behaviour is mixed in from
 several modules, specs are added to display the wrong behaviour

---
 lib/dm-core/model.rb                   | 16 ++++---
 lib/dm-core/model/property.rb          | 10 +++--
 lib/dm-core/model/relationship.rb      |  8 +++-
 spec/public/model/relationship_spec.rb | 61 ++++++++++++++++++++++++++
 4 files changed, 85 insertions(+), 10 deletions(-)

diff --git a/lib/dm-core/model.rb b/lib/dm-core/model.rb
index d4e377e70..3e7a8e787 100644
--- a/lib/dm-core/model.rb
+++ b/lib/dm-core/model.rb
@@ -209,11 +209,12 @@ def self.extra_extensions
     def self.extended(descendant)
       descendants << descendant
 
-      descendant.instance_variable_set(:@valid,         false)
-      descendant.instance_variable_set(:@base_model,    descendant)
-      descendant.instance_variable_set(:@storage_names, {})
-      descendant.instance_variable_set(:@default_order, {})
-
+      descendant.instance_eval do
+        @valid           = false unless instance_variable_defined?(:@valid)
+        @base_model    ||= descendant
+        @storage_names ||= {}
+        @default_order ||= {}
+      end
       descendant.extend(Chainable)
 
       extra_extensions.each { |mod| descendant.extend(mod)         }
@@ -224,6 +225,11 @@ def self.extended(descendant)
     def inherited(descendant)
       descendants << descendant
 
+      descendant.instance_eval do
+        @valid        = false unless instance_variable_defined?(:@valid)
+        @base_model ||= base_model
+      end
+
       descendant.instance_variable_set(:@valid,         false)
       descendant.instance_variable_set(:@base_model,    base_model)
       descendant.instance_variable_set(:@storage_names, @storage_names.dup)
diff --git a/lib/dm-core/model/property.rb b/lib/dm-core/model/property.rb
index 09fa15aee..fcc692675 100644
--- a/lib/dm-core/model/property.rb
+++ b/lib/dm-core/model/property.rb
@@ -7,13 +7,17 @@ module Property
       Model.append_extensions self, DataMapper::Property::Lookup
 
       def self.extended(model)
-        model.instance_variable_set(:@properties,               {})
-        model.instance_variable_set(:@field_naming_conventions, {})
+        model.instance_eval do
+          @properties                 = {}
+          @field_naming_conventions ||= {}
+        end
       end
 
 
       def inherited(model)
-        model.instance_variable_set(:@properties,               {})
+        model.instance_eval do
+          @properties ||= {}
+        end
         model.instance_variable_set(:@field_naming_conventions, @field_naming_conventions.dup)
 
         @properties.each do |repository_name, properties|
diff --git a/lib/dm-core/model/relationship.rb b/lib/dm-core/model/relationship.rb
index aeb5380ae..ec1c2cd15 100644
--- a/lib/dm-core/model/relationship.rb
+++ b/lib/dm-core/model/relationship.rb
@@ -17,7 +17,9 @@ module Relationship
       #
       # @api private
       def self.extended(model)
-        model.instance_variable_set(:@relationships, {})
+        model.instance_eval do
+          @relationships ||= {}
+        end
       end
 
       # When DataMapper model is inherited, relationships
@@ -25,7 +27,9 @@ def self.extended(model)
       #
       # @api private
       def inherited(model)
-        model.instance_variable_set(:@relationships, {})
+        model.instance_eval do
+          @relationships ||= {}
+        end
 
         @relationships.each do |repository_name, relationships|
           model_relationships = model.relationships(repository_name)
diff --git a/spec/public/model/relationship_spec.rb b/spec/public/model/relationship_spec.rb
index 2cacfc57b..ae5eaaf2c 100644
--- a/spec/public/model/relationship_spec.rb
+++ b/spec/public/model/relationship_spec.rb
@@ -1038,3 +1038,64 @@ class ::Company
     end
   end
 end
+
+describe DataMapper::Associations do
+  before :all do
+    module ::Vehicle
+      def self.included(base)
+        base.extend(ClassMethods)
+      end
+
+      module ClassMethods
+
+        def vehicle_with_wheels(*args)
+          include DataMapper::Resource
+
+          property :id, DataMapper::Property::Serial
+          property :license_plate, String
+        end
+      end
+    end
+
+    class Exhaust
+      include DataMapper::Resource
+
+      property :id, Serial
+      belongs_to :car
+    end
+
+    class Suspension
+      include DataMapper::Resource
+
+      property :id, Serial
+      property :brand, String
+    end
+
+    class Car
+      include DataMapper::Resource
+      has n, :suspensions
+    end
+
+    class Car
+      include DataMapper::Resource
+      include Vehicle
+
+      vehicle_with_wheels
+
+      property :number_of_seats, Integer
+      has n, :exhausts
+
+    end
+
+    DataMapper.finalize
+  end
+
+  it "should have all relationships when Resource is included once" do
+    Exhaust.relationships.any? {|r| r.name == :car }.should be_true
+  end
+
+  it "should not forget about relationships when Resource is included more than once" do
+    Car.relationships.any? {|r| r.name == :exhausts }.should be_true
+    Car.relationships.any? {|r| r.name == :suspensions }.should be_true
+  end
+end