This commit merges most of the work done by Piotr Sarnacki in his Ruby Summer of Code project.

His work brings several capabilities from app to engines, as routes, middleware stack, asset handling and much more. Please check Rails::Engine documentation for more refenrences.

Merge remote branch 'drogus/engines'

3 files changed, 102 insertions, 35 deletions

diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 198f0a18cb..e708b3fbcf 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -383,6 +383,37 @@ module ActiveRecord
           connection.send(method, *arguments, &block)
         end
       end
+
+      def copy(destination, sources)
+        copied = []
+
+        sources.each do |scope, path|
+          destination_migrations = ActiveRecord::Migrator.migrations(destination)
+          source_migrations = ActiveRecord::Migrator.migrations(path)
+          last = destination_migrations.last
+
+          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 ? last.version + 1 : 0).to_i
+            last = migration
+
+            new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")
+            FileUtils.cp(migration.filename, new_path)
+            copied << new_path
+          end
+        end
+
+        copied
+      end
+
+      def next_migration_number(number)
+        if ActiveRecord::Base.timestamped_migrations
+          [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
+        else
+          "%.3d" % number
+        end
+      end
     end
   end
 
@@ -390,7 +421,7 @@ module ActiveRecord
   # until they are needed
   class MigrationProxy
 
-    attr_accessor :name, :version, :filename
+    attr_accessor :name, :version, :filename, :scope
 
     delegate :migrate, :announce, :write, :to=>:migration
 
@@ -409,6 +440,8 @@ module ActiveRecord
 
   class Migrator#:nodoc:
     class << self
+      attr_writer :migrations_path
+
       def migrate(migrations_path, target_version = nil)
         case
           when target_version.nil?
@@ -441,10 +474,6 @@ module ActiveRecord
         self.new(direction, migrations_path, target_version).run
       end
 
-      def migrations_path
-        'db/migrate'
-      end
-
       def schema_migrations_table_name
         Base.table_name_prefix + 'schema_migrations' + Base.table_name_suffix
       end
@@ -468,6 +497,38 @@ module ActiveRecord
         name.table_name rescue "#{ActiveRecord::Base.table_name_prefix}#{name}#{ActiveRecord::Base.table_name_suffix}"
       end
 
+      def migrations_path
+        @migrations_path ||= 'db/migrate'
+      end
+
+      def migrations(path)
+        files = Dir["#{path}/[0-9]*_*.rb"]
+
+        migrations = files.inject([]) do |klasses, file|
+          version, name, scope = file.scan(/([0-9]+)_([_a-z0-9]*)\.?([_a-z0-9]*)?.rb/).first
+
+          raise IllegalMigrationNameError.new(file) unless version
+          version = version.to_i
+
+          if klasses.detect { |m| m.version == version }
+            raise DuplicateMigrationVersionError.new(version)
+          end
+
+          if klasses.detect { |m| m.name == name.camelize && m.scope == scope }
+            raise DuplicateMigrationNameError.new(name.camelize)
+          end
+
+          migration = MigrationProxy.new
+          migration.name     = name.camelize
+          migration.version  = version
+          migration.filename = file
+          migration.scope    = scope
+          klasses << migration
+        end
+
+        migrations.sort_by(&:version)
+      end
+
       private
 
       def move(direction, migrations_path, steps)
@@ -546,30 +607,7 @@ module ActiveRecord
 
     def migrations
       @migrations ||= begin
-        files = Dir["#{@migrations_path}/[0-9]*_*.rb"]
-
-        migrations = files.inject([]) do |klasses, file|
-          version, name = file.scan(/([0-9]+)_([_a-z0-9]*).rb/).first
-
-          raise IllegalMigrationNameError.new(file) unless version
-          version = version.to_i
-
-          if klasses.detect { |m| m.version == version }
-            raise DuplicateMigrationVersionError.new(version)
-          end
-
-          if klasses.detect { |m| m.name == name.camelize }
-            raise DuplicateMigrationNameError.new(name.camelize)
-          end
-
-          migration = MigrationProxy.new
-          migration.name     = name.camelize
-          migration.version  = version
-          migration.filename = file
-          klasses << migration
-        end
-
-        migrations = migrations.sort_by { |m| m.version }
+        migrations = self.class.migrations(@migrations_path)
         down? ? migrations.reverse : migrations
       end
     end
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index b1aad0d496..aedda26ba5 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -2,6 +2,29 @@ namespace :db do
   task :load_config => :rails_env do
     require 'active_record'
     ActiveRecord::Base.configurations = Rails.application.config.database_configuration
+    ActiveRecord::Migrator.migrations_path = Rails.application.config.paths.db.migrate.to_a.first
+  end
+
+  desc "Copies missing migrations from Railties (e.g. plugins, engines). You can specify Railties to use with FROM=railtie1,railtie2"
+  task :copy_migrations => :load_config do
+    to_load = ENV["FROM"].blank? ? :all : ENV["FROM"].split(",").map {|n| n.strip }
+    railties = {}
+    Rails.application.railties.all do |railtie|
+      next unless to_load == :all || to_load.include?(railtie.railtie_name)
+
+      if railtie.config.respond_to?(:paths) && railtie.config.paths.db
+        railties[railtie.railtie_name] = railtie.config.paths.db.migrate.to_a.first
+      end
+    end
+
+    copied = ActiveRecord::Migration.copy(ActiveRecord::Migrator.migrations_path, railties)
+
+    if copied.blank?
+      puts "No migrations were copied, project is up to date."
+    else
+      puts "The following migrations were copied:"
+      puts copied.map{ |path| File.basename(path) }.join("\n")
+    end
   end
 
   namespace :create do
@@ -139,7 +162,7 @@ namespace :db do
   desc "Migrate the database (options: VERSION=x, VERBOSE=false)."
   task :migrate => :environment do
     ActiveRecord::Migration.verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
-    ActiveRecord::Migrator.migrate("db/migrate/", ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
+    ActiveRecord::Migrator.migrate(ActiveRecord::Migrator.migrations_path, ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
     Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
   end
 
@@ -162,7 +185,7 @@ namespace :db do
     task :up => :environment do
       version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
       raise "VERSION is required" unless version
-      ActiveRecord::Migrator.run(:up, "db/migrate/", version)
+      ActiveRecord::Migrator.run(:up, ActiveRecord::Migrator.migrations_path, version)
       Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
     end
 
@@ -170,7 +193,7 @@ namespace :db do
     task :down => :environment do
       version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
       raise "VERSION is required" unless version
-      ActiveRecord::Migrator.run(:down, "db/migrate/", version)
+      ActiveRecord::Migrator.run(:down, ActiveRecord::Migrator.migrations_path, version)
       Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
     end
 
@@ -208,14 +231,14 @@ namespace :db do
   desc 'Rolls the schema back to the previous version (specify steps w/ STEP=n).'
   task :rollback => :environment do
     step = ENV['STEP'] ? ENV['STEP'].to_i : 1
-    ActiveRecord::Migrator.rollback('db/migrate/', step)
+    ActiveRecord::Migrator.rollback(ActiveRecord::Migrator.migrations_path, step)
     Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
   end
 
   # desc 'Pushes the schema to the next version (specify steps w/ STEP=n).'
   task :forward => :environment do
     step = ENV['STEP'] ? ENV['STEP'].to_i : 1
-    ActiveRecord::Migrator.forward('db/migrate/', step)
+    ActiveRecord::Migrator.forward(ActiveRecord::Migrator.migrations_path, step)
     Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
   end
 
@@ -260,7 +283,7 @@ namespace :db do
   # desc "Raises an error if there are pending migrations"
   task :abort_if_pending_migrations => :environment do
     if defined? ActiveRecord
-      pending_migrations = ActiveRecord::Migrator.new(:up, 'db/migrate').pending_migrations
+      pending_migrations = ActiveRecord::Migrator.new(:up, ActiveRecord::Migrator.migrations_path).pending_migrations
 
       if pending_migrations.any?
         puts "You have #{pending_migrations.size} pending migrations:"
diff --git a/activerecord/lib/rails/generators/active_record.rb b/activerecord/lib/rails/generators/active_record.rb
index 26bc977e19..4b3d1db216 100644
--- a/activerecord/lib/rails/generators/active_record.rb
+++ b/activerecord/lib/rails/generators/active_record.rb
@@ -14,6 +14,12 @@ module ActiveRecord
       def self.base_root
         File.dirname(__FILE__)
       end
+
+      # Implement the required interface for Rails::Generators::Migration.
+      def self.next_migration_number(dirname) #:nodoc:
+        next_migration_number = current_migration_number(dirname) + 1
+        ActiveRecord::Migration.next_migration_number(next_migration_number)
+      end
     end
   end
 end