Allow destructive replacement on has_one relations when using create_…

… methods. Fixes #1442.

CHANGELOG.md

@@ -13,6 +13,9 @@ For instructions on upgrading to newer versions, visit
 * \#1445 Prevent duplicate documents in the loaded array on the target
   enumerable for relational associations.
 
+* \#1442 When using create_ methods for has one relations, the appropriate
+  destructive methods now get called when replacing an existing document.
+
 * \#1431 Enumerable context should add to the loaded array post yield, so
   that methods like #any? that short circuit based on the value of the block
   dont falsely have extra documents.

lib/mongoid/relations/builders.rb

@@ -32,6 +32,23 @@ module Relations #:nodoc:
     module Builders
       extend ActiveSupport::Concern
 
+      private
+
+      # Parse out the attributes and the options from the args passed to a
+      # build_ or create_ methods.
+      #
+      # @example Parse the args.
+      #   doc.parse_args(:name => "Joe")
+      #
+      # @param [ Array ] args The arguments.
+      #
+      # @return [ Array<Hash> ] The attributes and options.
+      #
+      # @since 2.3.4
+      def parse_args(*args)
+        [ args.first || {}, args.size > 1 ? args[1] : {} ]
+      end
+
       module ClassMethods #:nodoc:
 
         # Defines a builder method for an embeds_one relation. This is
@@ -48,8 +65,7 @@ module ClassMethods #:nodoc:
         def builder(name, metadata)
           tap do
             define_method("build_#{name}") do |*args|
-              attributes = args.first || {}
-              options = args.size > 1 ? args[1] : {}
+              attributes, options = parse_args(*args)
               document = Factory.build(metadata.klass, attributes, options)
               _building do
                 send("#{name}=", document)
@@ -70,10 +86,12 @@ def builder(name, metadata)
         # @return [ Class ] The class being set up.
         #
         # @since 2.0.0.rc.1
-        def creator(name)
+        def creator(name, metadata)
           tap do
             define_method("create_#{name}") do |*args|
-              send("build_#{name}", *args).tap { |doc| doc.save }
+              attributes, options = parse_args(*args)
+              document = Factory.build(metadata.klass, attributes, options)
+              send("#{name}=", document).tap { |doc| doc.save }
             end
           end
         end

lib/mongoid/relations/macros.rb

@@ -103,7 +103,7 @@ def embeds_many(name, options = {}, &block)
         def embeds_one(name, options = {}, &block)
           characterize(name, Embedded::One, options, &block).tap do |meta|
             relate(name, meta)
-            builder(name, meta).creator(name)
+            builder(name, meta).creator(name, meta)
             validates_relation(meta)
           end
         end
@@ -219,7 +219,7 @@ def has_one(name, options = {}, &block)
           characterize(name, Referenced::One, options, &block).tap do |meta|
             relate(name, meta)
             reference(meta)
-            builder(name, meta).creator(name).autosave(meta)
+            builder(name, meta).creator(name, meta).autosave(meta)
             validates_relation(meta)
           end
         end

spec/functional/mongoid/callbacks_spec.rb

@@ -186,12 +186,12 @@
             Band.create(:name => "Moderat")
           end
 
-          let!(:label) do
-            band.create_label(:name => "Mute")
-          end
-
           context "when the child is dirty" do
 
+            let!(:label) do
+              band.create_label(:name => "Mute")
+            end
+
             before do
               label.name = "Nothing"
               band.save
@@ -204,6 +204,10 @@
 
           context "when the child is not dirty" do
 
+            let!(:label) do
+              band.build_label(:name => "Mute")
+            end
+
             before do
               band.save
             end

spec/functional/mongoid/criterion/inclusion_spec.rb

@@ -409,8 +409,8 @@
         criteria.should eq([ person ])
       end
 
-      it "inserts the first document into the identity map" do
-        Mongoid::IdentityMap[Game][game_one.id].should eq(game_one)
+      it "deletes the replaced document from the identity map" do
+        Mongoid::IdentityMap[Game][game_one.id].should be_nil
       end
 
       it "inserts the second document into the identity map" do
@@ -491,8 +491,8 @@
         Mongoid::IdentityMap[Post][post_two.id].should eq(post_two)
       end
 
-      it "inserts the first has one document into the identity map" do
-        Mongoid::IdentityMap[Game][game_one.id].should eq(game_one)
+      it "removes the first has one document from the identity map" do
+        Mongoid::IdentityMap[Game][game_one.id].should be_nil
       end
 
       it "inserts the second has one document into the identity map" do

spec/functional/mongoid/relations/builders_spec.rb

@@ -2,6 +2,10 @@
 
 describe Mongoid::Relations::Builders do
 
+  before do
+    [ Person, Game ].each(&:delete_all)
+  end
+
   describe "#build_#\{name}" do
 
     let(:person) do
@@ -64,9 +68,43 @@
         end
       end
     end
+
+    context "when the parent is persisted" do
+
+      let(:person) do
+        Person.create(:ssn => "123-45-1234")
+      end
+
+      context "when the relation is a has one" do
+
+        let!(:game_one) do
+          person.create_game(:name => "Starcraft")
+        end
+
+        context "when a document already exists" do
+
+          let!(:game_two) do
+            person.create_game(:name => "Skyrim")
+          end
+
+          it "replaces the existing document" do
+            person.game.should eq(game_two)
+          end
+
+          it "persists the change" do
+            person.game(true).should eq(game_two)
+          end
+
+          it "removes the old document from the database" do
+            Game.collection.count.should eq(1)
+          end
+        end
+      end
+    end
   end
 
   describe "#build" do
+
     context "with criteria applied" do
 
       let(:person) { Person.new }
@@ -76,7 +114,6 @@
 
       it { should be_a_kind_of(Service) }
       it { should_not be_persisted }
-
     end
   end
 end

spec/unit/mongoid/relations/builders_spec.rb

@@ -66,21 +66,29 @@ class TestClass
 
   describe ".creator" do
 
+    let(:metadata) do
+      Mongoid::Relations::Metadata.new(
+        :name => :name,
+        :relation => relation,
+        :inverse_class_name => "Person"
+      )
+    end
+
     let(:document) do
       klass.new
     end
 
     before do
       document.instance_variable_set(:@attributes, {})
-      klass.creator("name")
+      klass.creator("name", metadata)
     end
 
     it "defines a create_* method" do
       document.should respond_to(:create_name)
     end
 
     it "returns self" do
-      klass.creator("name").should == klass
+      klass.creator("name", metadata).should == klass
     end
 
     context "defined methods" do