Added prevention of duplicate migrations from the generator #2240 [fbeausoleil@ftml.net]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2320 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

railties/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Added prevention of duplicate migrations from the generator #2240 [fbeausoleil@ftml.net]
+
 * Add db_schema_dump and db_schema_import rake tasks to work with the new ActiveRecord::SchemaDumper (for dumping a schema to and reading a schema from a ruby file).
 
 * Reformed all the config/environments/* files to conform to the new Rails::Configuration approach. Fully backwards compatible.

railties/lib/rails_generator/generators/components/migration/migration_generator.rb

@@ -2,6 +2,8 @@ class MigrationGenerator < Rails::Generator::NamedBase
   def manifest
     record do |m|
       m.directory File.join('db/migrate')
+      existing_migrations = Dir.glob("db/migrate/[0-9]*_#{file_name}.rb")
+      raise "Another migration already exists with the same name" unless existing_migrations.empty?
       next_migration_number = Dir.glob("db/migrate/[0-9]*.*").size + 1
       m.template 'migration.rb', File.join('db/migrate', "#{next_migration_number}_#{file_name}.rb")
     end