Fix copying migrations to empty directory

activerecord/lib/active_record/migration.rb

@@ -395,7 +395,7 @@ def copy(destination, sources)
           source_migrations.each do |migration|
             next if destination_migrations.any? { |m| m.name == migration.name && m.scope == scope.to_s }
 
-            migration.version = next_migration_number(last.version + 1).to_i
+            migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
             last = migration
 
             new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")

activerecord/test/cases/migration_test.rb

@@ -1985,6 +1985,20 @@ def test_copying_migrations_with_timestamps_to_destination_with_timestamps_in_fu
     ensure
       clear
     end
+
+    def test_copying_migrations_to_empty_directory
+      @migrations_path = MIGRATIONS_ROOT + "/empty"
+      @existing_migrations = []
+
+      Time.travel_to(created_at = Time.utc(2010, 7, 26, 10, 10, 10)) do
+        copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+        assert File.exists?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+        assert File.exists?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+        assert_equal 2, copied.length
+      end
+    ensure
+      clear
+    end
   end
 end