Fixup UUID generation.

Support the ability to pass in a list of projects that can be used to generate deterministic UUIDs, and also initially pass into UUID generation the project basename such that we have unique UUIDs across all projects.

lib/xcodeproj/project.rb

@@ -388,7 +388,11 @@ def dirty?
     # @return [void]
     #
     def predictabilize_uuids
-      UUIDGenerator.new(self).generate!
+      UUIDGenerator.new([self]).generate!
+    end
+
+    def self.predictabilize_uuids(projects)
+      UUIDGenerator.new(projects).generate!
     end
 
     public

lib/xcodeproj/project/uuid_generator.rb

@@ -3,45 +3,55 @@ class Project
     class UUIDGenerator
       require 'digest'
 
-      def initialize(project)
-        @project = project
-        @new_objects_by_uuid = {}
+      def initialize(projects)
+        @projects = projects
         @paths_by_object = {}
       end
 
       def generate!
-        all_objects = @project.objects
-        generate_paths(@project.root_object)
-        switch_uuids(all_objects)
-        verify_no_duplicates!(all_objects)
-        fixup_uuid_references
-        @project.instance_variable_set(:@generated_uuids, @project.instance_variable_get(:@available_uuids))
-        @project.instance_variable_set(:@objects_by_uuid, @new_objects_by_uuid)
+        generate_all_paths_by_objects(@projects)
+
+        new_objects_by_project = Hash[@projects.map do |project|
+          [project, switch_uuids(project)]
+        end]
+        all_new_objects_by_project = new_objects_by_project.values.map { |new_objects_by_uuid| new_objects_by_uuid.values }.flatten
+        all_objects_by_uuid = @projects.map { |project| project.objects_by_uuid }.inject(:merge)
+        all_objects = @projects.map { |project| project.objects }.flatten
+        verify_no_duplicates!(all_objects, all_new_objects_by_project)
+        @projects.each { |project| fixup_uuid_references(project, all_objects_by_uuid) }
+        new_objects_by_project.each do |project, new_objects_by_uuid|
+          project.instance_variable_set(:@generated_uuids, project.instance_variable_get(:@available_uuids))
+          project.instance_variable_set(:@objects_by_uuid, new_objects_by_uuid)
+        end
       end
 
       private
 
       UUID_ATTRIBUTES = [:remote_global_id_string, :container_portal, :target_proxy].freeze
 
-      def verify_no_duplicates!(all_objects)
-        duplicates = all_objects - @new_objects_by_uuid.values
+      def verify_no_duplicates!(all_objects, all_new_objects)
+        duplicates = all_objects - all_new_objects
         UserInterface.warn "[Xcodeproj] Generated duplicate UUIDs:\n\n" <<
           duplicates.map { |d| "#{d.isa} -- #{@paths_by_object[d]}" }.join("\n") unless duplicates.empty?
       end
 
-      def fixup_uuid_references
+      def fixup_uuid_references(target_project, all_objects_by_uuid)
         fixup = ->(object, attr) do
-          if object.respond_to?(attr) && link = @project.objects_by_uuid[object.send(attr)]
+          if object.respond_to?(attr) && link = all_objects_by_uuid[object.send(attr)]
             object.send(:"#{attr}=", link.uuid)
           end
         end
-        @project.objects.each do |object|
+        target_project.objects.each do |object|
           UUID_ATTRIBUTES.each do |attr|
             fixup[object, attr]
           end
         end
       end
 
+      def generate_all_paths_by_objects(projects)
+        projects.each { |project| generate_paths(project.root_object, project.path.basename.to_s) }
+      end
+
       def generate_paths(object, path = '')
         existing = @paths_by_object[object] || path
         return existing if @paths_by_object.key?(object)
@@ -67,14 +77,16 @@ def generate_paths(object, path = '')
         end
       end
 
-      def switch_uuids(objects)
-        @project.mark_dirty!
-        objects.each do |object|
+      def switch_uuids(project)
+        new_objects_by_uuid = {}
+        project.mark_dirty!
+        project.objects.each do |object|
           next unless path = @paths_by_object[object]
           uuid = uuid_for_path(path)
           object.instance_variable_set(:@uuid, uuid)
-          @new_objects_by_uuid[uuid] = object
+          new_objects_by_uuid[uuid] = object
         end
+        new_objects_by_uuid
       end
 
       def uuid_for_path(path)

spec/project_spec.rb

@@ -480,20 +480,36 @@ module ProjectSpecs
           project
         end
 
+        it 'not have the same UUIDS' do
+          create_project[0].uuids.sort.should != create_project[1].uuids.sort
+        end
+
         it 'have the same UUIDS' do
-          create_project[0].uuids.sort.should == create_project[1].uuids.sort
+          create_project[0].uuids.sort.should == create_project[0].uuids.sort
+        end
+
+        it 'always has the same root object UUID, for the same path' do
+          project = Xcodeproj::Project.new('path1.xcodeproj')
+          project.add_build_configuration('Config', :debug)
+          project.predictabilize_uuids
+          project.root_object.uuid.should == 'BB3CBEC84BD00C24CC882BA09F25FC35'
+
+          project = Xcodeproj::Project.new('path1.xcodeproj')
+          project.add_build_configuration('Config', :release)
+          project.predictabilize_uuids
+          project.root_object.uuid.should == 'BB3CBEC84BD00C24CC882BA09F25FC35'
         end
 
-        it 'always has the same root object UUID, even for different paths' do
+        it 'has different root object UUID, for different paths' do
           project = Xcodeproj::Project.new('path1.xcodeproj')
           project.add_build_configuration('Config', :debug)
           project.predictabilize_uuids
-          project.root_object.uuid.should == 'D41D8CD98F00B204E9800998ECF8427E'
+          project.root_object.uuid.should == 'BB3CBEC84BD00C24CC882BA09F25FC35'
 
           project = Xcodeproj::Project.new('path2.xcodeproj')
           project.add_build_configuration('Config', :release)
           project.predictabilize_uuids
-          project.root_object.uuid.should == 'D41D8CD98F00B204E9800998ECF8427E'
+          project.root_object.uuid.should == '58C5CB80A8C53842A0F017EE22887DF0'
         end
 
         Pathname.glob("#{fixture_path}/**/*.xcodeproj").each do |path|