Merge pull request ionia-corporation#83 from DanOlson/fix-nil-belongs-to

Nil return value on belongs_to association should be handled gracefully

lib/active_force/association.rb

@@ -1,5 +1,6 @@
 require 'active_force/association/association'
 require 'active_force/association/eager_load_projection_builder'
+require 'active_force/association/relation_model_builder'
 require 'active_force/association/has_many_association'
 require 'active_force/association/belongs_to_association'
 

lib/active_force/association/association.rb

@@ -1,14 +1,16 @@
 module ActiveForce
   module Association
     class Association
+      extend Forwardable
+      def_delegators :relation_model, :build
 
       attr_accessor :options, :relation_name
 
-      def initialize parent, relation_name, options
+      def initialize parent, relation_name, options = {}
         @parent        = parent
         @relation_name = relation_name
         @options       = options
-        build
+        define_relation_method
       end
 
       def relation_model
@@ -29,7 +31,7 @@ def relationship_name
       # could be 'Quota__r' or 'Account'.
       def represents_sfdc_table?(sfdc_table_name)
         name = sfdc_table_name.sub(/__r\z/, '').singularize
-        relationship_name.sub(/__c\z/, '') == name
+        relationship_name.sub(/__c\z|__r\z/, '') == name
       end
 
       def sfdc_association_field
@@ -38,10 +40,6 @@ def sfdc_association_field
 
       private
 
-      def build
-        define_relation_method
-      end
-
       def infer_foreign_key_from_model(model)
         name = model.custom_table? ? model.name : model.table_name
         "#{name.downcase}_id".to_sym

lib/active_force/association/relation_model_builder.rb

@@ -0,0 +1,70 @@
+module ActiveForce
+  module Association
+    class RelationModelBuilder
+      class << self
+        def build(association, value)
+          new(association, value).build_relation_model
+        end
+      end
+
+      def initialize(association, value)
+        @association = association
+        @value = value
+      end
+
+      def build_relation_model
+        klass = resolve_class
+        klass.new(@association, @value).call
+      end
+
+      private
+
+      def resolve_class
+        association_builder = @value.class.name.gsub('::', '_')
+        ActiveForce::Association.const_get "BuildFrom#{association_builder}"
+      rescue NameError
+        raise "Don't know how to build relation from #{@value.class.name}"
+      end
+    end
+
+    class AbstractBuildFrom
+      attr_reader :association, :value
+
+      def initialize(association, value)
+        @association = association
+        @value = value
+      end
+
+      def call
+        raise "Must implement #{self.class.name}#call"
+      end
+    end
+
+    class BuildFromHash < AbstractBuildFrom
+      def call
+        association.build value
+      end
+    end
+
+    class BuildFromArray < AbstractBuildFrom
+      def call
+        value.map { |mash| association.build mash }
+      end
+    end
+
+    class BuildFromNilClass < AbstractBuildFrom
+      def call
+        association.is_a?(BelongsToAssociation) ? nil : []
+      end
+    end
+
+    class BuildFromRestforce_SObject < BuildFromHash
+    end
+
+    class BuildFromRestforce_Mash < BuildFromHash
+    end
+
+    class BuildFromRestforce_Collection < BuildFromArray
+    end
+  end
+end

lib/active_force/sobject.rb

@@ -140,13 +140,9 @@ def reload
     end
 
     def write_value column, value
-      if [Hash, Array, NilClass].include?(value.class) and association = self.class.find_association(column)
+      if association = self.class.find_association(column)
         field = association.relation_name
-        value = case value
-        when Hash; association.relation_model.build value
-        when Array; value.map { |mash| association.relation_model.build mash }
-        when NilClass; []
-        end
+        value = Association::RelationModelBuilder.build(association, value)
       else
         field = mappings.invert[column]
         value = self.class.mapping.translate_value value, field unless value.nil?

spec/active_force/association/relation_model_builder_spec.rb

@@ -0,0 +1,62 @@
+require 'spec_helper'
+
+module ActiveForce
+  module Association
+    describe RelationModelBuilder do
+      let(:instance){ described_class.new association, value }
+
+      describe '#build_relation_model' do
+        context 'has_many' do
+          let(:association){ HasManyAssociation.new Post, :comments }
+
+          context 'with values' do
+            let(:value) do
+              build_restforce_collection([
+                Restforce::SObject.new({'Id' => '213', 'PostId' => '123'}),
+                Restforce::SObject.new({'Id' => '214', 'PostId' => '123'})
+              ])
+            end
+
+            it 'returns an array of Comments' do
+              comments = instance.build_relation_model
+              expect(comments).to be_a Array
+              expect(comments.all?{ |c| c.is_a? Comment }).to be true
+            end
+          end
+
+          context 'without values' do
+            let(:value){ nil }
+
+            it 'returns an empty array' do
+              comments = instance.build_relation_model
+              expect(comments).to be_a Array
+              expect(comments).to be_empty
+            end
+          end
+        end
+
+        context 'belongs_to' do
+          let(:association){ BelongsToAssociation.new(Comment, :post) }
+
+          context 'with a value' do
+            let(:value) do
+              build_restforce_sobject 'Id' => '213'
+            end
+
+            it 'returns a post' do
+              expect(instance.build_relation_model).to be_a Post
+            end
+          end
+
+          context 'without a value' do
+            let(:value){ nil }
+
+            it 'returns nil' do
+              expect(instance.build_relation_model).to be_nil
+            end
+          end
+        end
+      end
+    end
+  end
+end