Speed up boot by tsorting as infrequently as possible

railties/lib/rails/application.rb

@@ -178,7 +178,7 @@ module Rails
       railties.all { |r| initializers += r.initializers }
       initializers += super
       initializers += Finisher.initializers_for(self)
-      initializers
+      Collection.new(initializers)
     end
 
   protected

railties/lib/rails/initializable.rb

@@ -39,11 +39,6 @@ module Rails
         select { |i| i.before == initializer.name || i.name == initializer.after }.each(&block)
       end
 
-      def initialize(initializers = [])
-        super(initializers)
-        replace(tsort)
-      end
-
       def +(other)
         Collection.new(to_a + other.to_a)
       end
@@ -51,7 +46,7 @@ module Rails
 
     def run_initializers(*args)
       return if instance_variable_defined?(:@ran)
-      initializers.each do |initializer|
+      initializers.tsort.each do |initializer|
         initializer.run(*args)
       end
       @ran = true
@@ -94,4 +89,4 @@ module Rails
       end
     end
   end
-end
+end

railties/test/railties/engine_test.rb

@@ -41,7 +41,7 @@ module RailtiesTest
 
       boot_rails
 
-      initializers = Rails.application.initializers
+      initializers = Rails.application.initializers.tsort
       index        = initializers.index { |i| i.name == "dummy_initializer" }
       selection    = initializers[(index-3)..(index)].map(&:name).map(&:to_s)