Port fast reloadable templates from rails-dev-boost.

17 files changed, 269 insertions, 124 deletions

diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
index 51b375fef3..3e7725570f 100644
--- a/actionmailer/test/abstract_unit.rb
+++ b/actionmailer/test/abstract_unit.rb
@@ -19,6 +19,7 @@ ActionView::Template.register_template_handler :bak, lambda { |template| "Lame b
 
 $:.unshift "#{File.dirname(__FILE__)}/fixtures/helpers"
 
+ActionView::Base.cache_template_loading = true
 FIXTURE_LOAD_PATH = File.join(File.dirname(__FILE__), 'fixtures')
 ActionMailer::Base.template_root = FIXTURE_LOAD_PATH
 
diff --git a/actionmailer/test/mail_service_test.rb b/actionmailer/test/mail_service_test.rb
index 1e04531753..0934d3537f 100644
--- a/actionmailer/test/mail_service_test.rb
+++ b/actionmailer/test/mail_service_test.rb
@@ -975,7 +975,7 @@ end
 
 class InheritableTemplateRootTest < Test::Unit::TestCase
   def test_attr
-    expected = "#{File.dirname(__FILE__)}/fixtures/path.with.dots"
+    expected = ("#{File.dirname(__FILE__)}/fixtures/path.with.dots").sub(/\.\//, '')
     assert_equal expected, FunkyPathMailer.template_root.to_s
 
     sub = Class.new(FunkyPathMailer)
diff --git a/actionpack/lib/action_controller/rescue.rb b/actionpack/lib/action_controller/rescue.rb
index 40aa7cdd57..242c8da920 100644
--- a/actionpack/lib/action_controller/rescue.rb
+++ b/actionpack/lib/action_controller/rescue.rb
@@ -38,7 +38,7 @@ module ActionController #:nodoc:
       'ActionView::TemplateError'         => 'template_error'
     }
 
-    RESCUES_TEMPLATE_PATH = ActionView::Template::Path.new(
+    RESCUES_TEMPLATE_PATH = ActionView::Template::EagerPath.new_and_loaded(
       File.join(File.dirname(__FILE__), "templates"))
 
     def self.included(base) #:nodoc:
diff --git a/actionpack/lib/action_view.rb b/actionpack/lib/action_view.rb
index 0b710bd8d9..1f1ff9dd05 100644
--- a/actionpack/lib/action_view.rb
+++ b/actionpack/lib/action_view.rb
@@ -44,6 +44,7 @@ module ActionView
   autoload :Renderable, 'action_view/renderable'
   autoload :RenderablePartial, 'action_view/renderable_partial'
   autoload :Template, 'action_view/template'
+  autoload :ReloadableTemplate, 'action_view/reloadable_template'
   autoload :TemplateError, 'action_view/template_error'
   autoload :TemplateHandler, 'action_view/template_handler'
   autoload :TemplateHandlers, 'action_view/template_handlers'
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 3134807a08..4198725e0d 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -182,10 +182,15 @@ module ActionView #:nodoc:
     # that alert()s the caught exception (and then re-raises it).
     cattr_accessor :debug_rjs
 
-    # Specify whether to check whether modified templates are recompiled without a restart
+    # Specify whether templates should be cached. Otherwise the file we be read everytime it is accessed.
+    # Automaticaly reloading templates are not thread safe and should only be used in development mode.
     @@cache_template_loading = false
     cattr_accessor :cache_template_loading
 
+    def self.cache_template_loading?
+      ActionController::Base.allow_concurrency || cache_template_loading
+    end
+
     attr_internal :request
 
     delegate :request_forgery_protection_token, :template, :params, :session, :cookies, :response, :headers,
@@ -226,6 +231,8 @@ module ActionView #:nodoc:
 
     def view_paths=(paths)
       @view_paths = self.class.process_view_paths(paths)
+      # we might be using ReloadableTemplates, so we need to let them know this a new request
+      @view_paths.load!
     end
 
     # Returns the result of a render that's dictated by the options hash. The primary options are:
@@ -247,8 +254,8 @@ module ActionView #:nodoc:
         if options[:layout]
           _render_with_layout(options, local_assigns, &block)
         elsif options[:file]
-          template = self.view_paths.find_template(options[:file], template_format)
-          template.render_template(self, options[:locals])
+          tempalte = self.view_paths.find_template(options[:file], template_format)
+          tempalte.render_template(self, options[:locals])
         elsif options[:partial]
           render_partial(options)
         elsif options[:inline]
diff --git a/actionpack/lib/action_view/partials.rb b/actionpack/lib/action_view/partials.rb
index 6fe4dbf375..9e5e0f786e 100644
--- a/actionpack/lib/action_view/partials.rb
+++ b/actionpack/lib/action_view/partials.rb
@@ -235,5 +235,6 @@ module ActionView
 
         self.view_paths.find_template(path, self.template_format)
       end
+      memoize :_pick_partial_template
   end
 end
diff --git a/actionpack/lib/action_view/paths.rb b/actionpack/lib/action_view/paths.rb
index e14b21221c..41f9f486e5 100644
--- a/actionpack/lib/action_view/paths.rb
+++ b/actionpack/lib/action_view/paths.rb
@@ -2,12 +2,16 @@ module ActionView #:nodoc:
   class PathSet < Array #:nodoc:
     def self.type_cast(obj)
       if obj.is_a?(String)
-        Template::Path.new(obj)
+        if Base.cache_template_loading?
+          Template::EagerPath.new(obj.to_s)
+        else
+          ReloadableTemplate::ReloadablePath.new(obj.to_s)
+        end
       else
         obj
       end
     end
-
+    
     def initialize(*args)
       super(*args).map! { |obj| self.class.type_cast(obj) }
     end
@@ -31,9 +35,14 @@ module ActionView #:nodoc:
     def unshift(*objs)
       super(*objs.map { |obj| self.class.type_cast(obj) })
     end
+    
+    def load!
+      each(&:load!)
+    end
 
-    def find_template(template_path, format = nil)
-      return template_path if template_path.respond_to?(:render)
+    def find_template(original_template_path, format = nil)
+      return original_template_path if original_template_path.respond_to?(:render)
+      template_path = original_template_path.sub(/^\//, '')
 
       each do |load_path|
         if format && (template = load_path["#{template_path}.#{I18n.locale}.#{format}"])
@@ -52,11 +61,9 @@ module ActionView #:nodoc:
         end
       end
 
-      if File.exist?(template_path)
-        return Template.new(template_path, template_path[0] == 47 ? "" : ".")
-      end
+      return Template.new(original_template_path, original_template_path =~ /\A\// ? "" : ".") if File.file?(original_template_path)
 
-      raise MissingTemplate.new(self, template_path, format)
+      raise MissingTemplate.new(self, original_template_path, format)
     end
   end
 end
diff --git a/actionpack/lib/action_view/reloadable_template.rb b/actionpack/lib/action_view/reloadable_template.rb
new file mode 100644
index 0000000000..3081be60fd
--- /dev/null
+++ b/actionpack/lib/action_view/reloadable_template.rb
@@ -0,0 +1,120 @@
+module ActionView #:nodoc:
+  class ReloadableTemplate < Template
+
+    class TemplateDeleted < ActionView::ActionViewError
+    end
+
+    class ReloadablePath < Template::Path
+
+      def initialize(path)
+        super
+        @paths = {}
+        new_request!
+      end
+
+      def new_request!
+        @disk_cache = {}
+      end
+      alias_method :load!, :new_request!
+
+      def [](path)
+        if found_template = @paths[path]
+          begin
+            found_template.reset_cache_if_stale!
+          rescue TemplateDeleted
+            unregister_template(found_template)
+            self[path]
+          end
+        else
+          load_all_templates_from_dir(templates_dir_from_path(path))
+          @paths[path]
+        end
+      end
+
+      def register_template_from_file(template_file_path)
+        if !@paths[template_relative_path = template_file_path.split("#{@path}/").last] && File.file?(template_file_path)
+          register_template(ReloadableTemplate.new(template_relative_path, self))
+        end
+      end
+
+      def register_template(template)
+        template.accessible_paths.each do |path|
+          @paths[path] = template
+        end
+      end
+
+      # remove (probably deleted) template from cache
+      def unregister_template(template)
+        template.accessible_paths.each do |template_path|
+          @paths.delete(template_path) if @paths[template_path] == template
+        end
+        # fill in any newly created gaps
+        @paths.values.uniq.each do |template|
+          template.accessible_paths.each {|path| @paths[path] ||= template}
+        end
+      end
+
+      # load all templates from the directory of the requested template
+      def load_all_templates_from_dir(dir)
+        # hit disk only once per template-dir/request
+        @disk_cache[dir] ||= template_files_from_dir(dir).each {|template_file| register_template_from_file(template_file)}
+      end
+
+      def templates_dir_from_path(path)
+        dirname = File.dirname(path)
+        File.join(@path, dirname == '.' ? '' : dirname)
+      end
+
+      # get all the template filenames from the dir
+      def template_files_from_dir(dir)
+        Dir.glob(File.join(dir, '*'))
+      end
+
+    end
+
+    module Unfreezable
+      def freeze; self; end
+    end
+
+    def initialize(*args)
+      super
+      @compiled_methods = []
+      
+      # we don't ever want to get frozen
+      extend Unfreezable
+    end
+
+    def mtime
+      File.mtime(filename)
+    end
+
+    attr_accessor :previously_last_modified
+
+    def stale?
+      previously_last_modified.nil? || previously_last_modified < mtime
+    rescue Errno::ENOENT => e
+      undef_my_compiled_methods!
+      raise TemplateDeleted
+    end
+
+    def reset_cache_if_stale!
+      if stale?
+        flush_cache 'source', 'compiled_source'
+        undef_my_compiled_methods!
+        @previously_last_modified = mtime
+      end
+      self
+    end
+
+    def undef_my_compiled_methods!
+      @compiled_methods.each {|comp_method| ActionView::Base::CompiledTemplates.send(:remove_method, comp_method)}
+      @compiled_methods.clear
+    end
+
+    def compile!(render_symbol, local_assigns)
+      super
+      @compiled_methods << render_symbol
+    end
+
+  end
+end
diff --git a/actionpack/lib/action_view/renderable.rb b/actionpack/lib/action_view/renderable.rb
index 16cdd0162e..41080ed629 100644
--- a/actionpack/lib/action_view/renderable.rb
+++ b/actionpack/lib/action_view/renderable.rb
@@ -16,18 +16,8 @@ module ActionView
     memoize :handler
 
     def compiled_source
-      @compiled_at = Time.now
       handler.call(self)
     end
-    memoize :compiled_source
-
-    def compiled_at
-      @compiled_at
-    end
-
-    def defined_at
-      @defined_at ||= {}
-    end
 
     def method_name_without_locals
       ['_run', extension, method_segment].compact.join('_')
@@ -71,12 +61,8 @@ module ActionView
       def compile(local_assigns)
         render_symbol = method_name(local_assigns)
 
-        if self.is_a?(InlineTemplate)
+        if !Base::CompiledTemplates.method_defined?(render_symbol) || recompile?
           compile!(render_symbol, local_assigns)
-        else
-          if !Base::CompiledTemplates.method_defined?(render_symbol) || recompile?(render_symbol)
-            recompile!(render_symbol, local_assigns)
-          end
         end
       end
 
@@ -93,7 +79,6 @@ module ActionView
 
         begin
           ActionView::Base::CompiledTemplates.module_eval(source, filename, 0)
-          defined_at[render_symbol] = Time.now if respond_to?(:reloadable?) && reloadable?
         rescue Errno::ENOENT => e
           raise e # Missing template file, re-raise for Base to rescue
         rescue Exception => e # errors from template code
@@ -107,17 +92,8 @@ module ActionView
         end
       end
 
-      def recompile?(render_symbol)
-        !cached? || redefine?(render_symbol) || stale?
-      end
-
-      def recompile!(render_symbol, local_assigns)
-        compiled_source(:reload) if compiled_at.nil? || compiled_at < mtime
-        compile!(render_symbol, local_assigns)
-      end
-
-      def redefine?(render_symbol)
-        compiled_at && defined_at[render_symbol] && compiled_at > defined_at[render_symbol]
+      def recompile?
+        false
       end
   end
 end
diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index f2d3998d16..b8e2165ddf 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -6,14 +6,12 @@ module ActionView #:nodoc:
 
       def initialize(path)
         raise ArgumentError, "path already is a Path class" if path.is_a?(Path)
-        @path = path.freeze
+        @path = expand_path(path).freeze
       end
 
-      def load!
-        @paths = {}
-        templates_in_path do |template|
-          load_template(template)
-        end
+      def expand_path(path)
+        # collapse any directory dots in path ('.' or '..')
+        path.starts_with?('/') ? File.expand_path(path) : File.expand_path(path, '/').from(1)
       end
 
       def to_s
@@ -46,43 +44,51 @@ module ActionView #:nodoc:
       # etc. A format must be supplied to match a formated file. +hello/index+
       # will never match +hello/index.html.erb+.
       def [](path)
-        load! if @paths.nil?
-        @paths[path] || find_template(path)
       end
-
-      private
-        def templates_in_path
-          (Dir.glob("#{@path}/**/*/**") | Dir.glob("#{@path}/**")).each do |file|
-            yield create_template(file) unless File.directory?(file)
-          end
+      
+      def load!
+      end
+      
+      def self.new_and_loaded(path)
+        returning new(path) do |path|
+          path.load!
         end
+      end
+    end
 
-        def create_template(file)
-          Template.new(file.split("#{self}/").last, self)
-        end
+    class EagerPath < Path
+      def initialize(path)
+        super
+      end
 
-        def load_template(template)
+      def load!
+        return if @loaded
+        
+        @paths = {}
+        templates_in_path do |template|
           template.load!
           template.accessible_paths.each do |path|
             @paths[path] = template
           end
         end
+        @paths.freeze
+        @loaded = true
+      end
 
-        def matching_templates(template_path)
-          Dir.glob("#{@path}/#{template_path}.*").each do |file|
+      def [](path)
+        load! unless @loaded
+        @paths[path]
+      end
+      
+      private
+        def templates_in_path
+          (Dir.glob("#{@path}/**/*/**") | Dir.glob("#{@path}/**")).each do |file|
             yield create_template(file) unless File.directory?(file)
           end
         end
 
-        def find_template(path)
-          return nil if Base.cache_template_loading || ActionController::Base.allow_concurrency
-          matching_templates(path) do |template|
-            if template.accessible_paths.include?(path)
-              load_template(template)
-              return template
-            end
-          end
-          nil
+        def create_template(file)
+          Template.new(file.split("#{self}/").last, self)
         end
     end
 
@@ -171,14 +177,10 @@ module ActionView #:nodoc:
       @@exempt_from_layout.any? { |exempted| path =~ exempted }
     end
 
-    def mtime
-      File.mtime(filename)
-    end
-    memoize :mtime
-
     def source
       File.read(filename)
     end
+    memoize :source
 
     def method_segment
       relative_path.to_s.gsub(/([^a-zA-Z0-9_])/) { $1.ord }
@@ -192,27 +194,13 @@ module ActionView #:nodoc:
       if TemplateError === e
         e.sub_template_of(self)
         raise e
-      elsif Errno::ENOENT === e
-        raise MissingTemplate.new(view.view_paths, filename.sub("#{RAILS_ROOT}/#{load_path}/", ""))
       else
         raise TemplateError.new(self, view.assigns, e)
       end
     end
 
-    def stale?
-      reloadable? && (mtime < mtime(:reload))
-    end
-
     def load!
-      reloadable? ? memoize_all : freeze
-    end
-
-    def reloadable?
-      !(Base.cache_template_loading || ActionController::Base.allow_concurrency)
-    end
-
-    def cached?
-      ActionController::Base.perform_caching || !reloadable?
+      freeze
     end
 
     private
@@ -262,5 +250,5 @@ module ActionView #:nodoc:
 
         [base_path, name, locale, format, extension]
       end
- end
+  end
 end
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 07bd7ba71d..cdeee934d0 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -38,4 +38,8 @@ I18n.backend.store_translations 'pt-BR', {}
 ORIGINAL_LOCALES = I18n.available_locales.map(&:to_s).sort
 
 FIXTURE_LOAD_PATH = File.join(File.dirname(__FILE__), 'fixtures')
+ActionView::Base.cache_template_loading = true
 ActionController::Base.view_paths = FIXTURE_LOAD_PATH
+CACHED_VIEW_PATHS = ActionView::Base.cache_template_loading? ?
+                      ActionController::Base.view_paths :
+                      ActionController::Base.view_paths.map {|path| ActionView::Template::EagerPath.new(path.to_s)}
diff --git a/actionpack/test/controller/view_paths_test.rb b/actionpack/test/controller/view_paths_test.rb
index ac84e2dfcd..6468283270 100644
--- a/actionpack/test/controller/view_paths_test.rb
+++ b/actionpack/test/controller/view_paths_test.rb
@@ -41,31 +41,35 @@ class ViewLoadPathsTest < ActionController::TestCase
   def teardown
     ActiveSupport::Deprecation.behavior = @old_behavior
   end
+  
+  def assert_view_path_strings_are_equal(expected, actual)
+    assert_equal(expected.map {|path| path.sub(/\.\//, '')}, actual)
+  end
 
   def test_template_load_path_was_set_correctly
-    assert_equal [FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
   end
 
   def test_controller_appends_view_path_correctly
     @controller.append_view_path 'foo'
-    assert_equal [FIXTURE_LOAD_PATH, 'foo'], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo'], @controller.view_paths.map(&:to_s)
 
     @controller.append_view_path(%w(bar baz))
-    assert_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz'], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz'], @controller.view_paths.map(&:to_s)
 
     @controller.append_view_path(FIXTURE_LOAD_PATH)
-    assert_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
   end
 
   def test_controller_prepends_view_path_correctly
     @controller.prepend_view_path 'baz'
-    assert_equal ['baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal ['baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
 
     @controller.prepend_view_path(%w(foo bar))
-    assert_equal ['foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal ['foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
 
     @controller.prepend_view_path(FIXTURE_LOAD_PATH)
-    assert_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
   end
 
   def test_template_appends_view_path_correctly
@@ -73,10 +77,10 @@ class ViewLoadPathsTest < ActionController::TestCase
     class_view_paths = TestController.view_paths
 
     @controller.append_view_path 'foo'
-    assert_equal [FIXTURE_LOAD_PATH, 'foo'], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo'], @controller.view_paths.map(&:to_s)
 
     @controller.append_view_path(%w(bar baz))
-    assert_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz'], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal [FIXTURE_LOAD_PATH, 'foo', 'bar', 'baz'], @controller.view_paths.map(&:to_s)
     assert_equal class_view_paths, TestController.view_paths
   end
 
@@ -85,10 +89,10 @@ class ViewLoadPathsTest < ActionController::TestCase
     class_view_paths = TestController.view_paths
 
     @controller.prepend_view_path 'baz'
-    assert_equal ['baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal ['baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
 
     @controller.prepend_view_path(%w(foo bar))
-    assert_equal ['foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
+    assert_view_path_strings_are_equal ['foo', 'bar', 'baz', FIXTURE_LOAD_PATH], @controller.view_paths.map(&:to_s)
     assert_equal class_view_paths, TestController.view_paths
   end
 
diff --git a/actionpack/test/template/compiled_templates_test.rb b/actionpack/test/template/compiled_templates_test.rb
index 55fa346fb8..a8f8455a54 100644
--- a/actionpack/test/template/compiled_templates_test.rb
+++ b/actionpack/test/template/compiled_templates_test.rb
@@ -2,8 +2,21 @@ require 'abstract_unit'
 require 'controller/fake_models'
 
 class CompiledTemplatesTest < Test::Unit::TestCase
+  
   def setup
     @compiled_templates = ActionView::Base::CompiledTemplates
+
+    # first, if we are running the whole test suite with ReloadableTemplates
+    # try to undef all the methods through ReloadableTemplate's interfaces
+    unless ActionView::Base.cache_template_loading?
+      ActionController::Base.view_paths.each do |view_path|
+        view_path.paths.values.uniq!.each do |reloadable_template|
+          reloadable_template.undef_my_compiled_methods!
+        end
+      end
+    end
+
+    # just purge anything that's left
     @compiled_templates.instance_methods.each do |m|
       @compiled_templates.send(:remove_method, m) if m =~ /^_run_/
     end
@@ -35,17 +48,6 @@ class CompiledTemplatesTest < Test::Unit::TestCase
     end
   end
 
-  def test_compiled_template_will_always_be_recompiled_when_template_is_not_cached
-    with_caching(false) do
-      ActionView::Template.any_instance.expects(:recompile?).times(3).returns(true)
-      assert_equal 0, @compiled_templates.instance_methods.size
-      assert_equal "Hello world!", render(:file => "#{FIXTURE_LOAD_PATH}/test/hello_world.erb")
-      ActionView::Template.any_instance.expects(:compile!).times(3)
-      3.times { assert_equal "Hello world!", render(:file => "#{FIXTURE_LOAD_PATH}/test/hello_world.erb") }
-      assert_equal 1, @compiled_templates.instance_methods.size
-    end
-  end
-
   def test_template_changes_are_not_reflected_with_cached_template_loading
     with_caching(true) do
       with_reloading(false) do
@@ -63,9 +65,10 @@ class CompiledTemplatesTest < Test::Unit::TestCase
       with_reloading(true) do
         assert_equal "Hello world!", render(:file => "test/hello_world.erb")
         modify_template "test/hello_world.erb", "Goodbye world!" do
+          reset_mtime_of('test/hello_world.erb')
           assert_equal "Goodbye world!", render(:file => "test/hello_world.erb")
-          sleep(1) # Need to sleep so that the timestamp actually changes
         end
+        reset_mtime_of('test/hello_world.erb')
         assert_equal "Hello world!", render(:file => "test/hello_world.erb")
       end
     end
@@ -74,10 +77,15 @@ class CompiledTemplatesTest < Test::Unit::TestCase
   private
     def render(*args)
       view_paths = ActionController::Base.view_paths
-      assert_equal ActionView::Template::Path, view_paths.first.class
       ActionView::Base.new(view_paths, {}).render(*args)
     end
 
+    def reset_mtime_of(template_name)
+      unless ActionView::Base.cache_template_loading?
+        ActionController::Base.view_paths.find_template(template_name).previously_last_modified = 10.seconds.ago 
+      end
+    end
+
     def modify_template(template, content)
       filename = "#{FIXTURE_LOAD_PATH}/#{template}"
       old_content = File.read(filename)
@@ -100,12 +108,18 @@ class CompiledTemplatesTest < Test::Unit::TestCase
     end
 
     def with_reloading(reload_templates)
-      old_cache_template_loading = ActionView::Base.cache_template_loading
+      old_view_paths, old_cache_templates = ActionController::Base.view_paths, ActionView::Base.cache_template_loading
       begin
         ActionView::Base.cache_template_loading = !reload_templates
+        ActionController::Base.view_paths = view_paths_for(reload_templates)
         yield
       ensure
-        ActionView::Base.cache_template_loading = old_cache_template_loading
+        ActionController::Base.view_paths, ActionView::Base.cache_template_loading = old_view_paths, old_cache_templates
       end
     end
+
+    def view_paths_for(reload_templates)
+      # reloadable paths are cheap to create
+      reload_templates ? ActionView::PathSet.new(CACHED_VIEW_PATHS.map(&:to_s)) : CACHED_VIEW_PATHS
+    end
 end
diff --git a/actionpack/test/template/render_test.rb b/actionpack/test/template/render_test.rb
index 34e7e82366..107c625e32 100644
--- a/actionpack/test/template/render_test.rb
+++ b/actionpack/test/template/render_test.rb
@@ -243,13 +243,34 @@ module RenderTestCases
   end
 end
 
+module TemplatesSetupTeardown
+  def setup_view_paths_for(new_cache_template_loading)
+    @previous_cache_template_loading, ActionView::Base.cache_template_loading = ActionView::Base.cache_template_loading, new_cache_template_loading
+    view_paths = new_cache_template_loading ? CACHED_VIEW_PATHS : ActionView::Base.process_view_paths(CACHED_VIEW_PATHS.map(&:to_s))
+    assert_equal(new_cache_template_loading ? ActionView::Template::EagerPath : ActionView::ReloadableTemplate::ReloadablePath, view_paths.first.class)
+    setup_view(view_paths)
+  end
+  
+  def teardown
+    ActionView::Base.cache_template_loading = @previous_cache_template_loading
+  end
+end
+
 class CachedRenderTest < Test::Unit::TestCase
+  include TemplatesSetupTeardown
   include RenderTestCases
 
-  # Ensure view path cache is primed
   def setup
-    view_paths = ActionController::Base.view_paths
-    assert_equal ActionView::Template::Path, view_paths.first.class
-    setup_view(view_paths)
+    setup_view_paths_for(cache_templates = true)
   end
 end
+
+class ReloadableRenderTest < Test::Unit::TestCase
+  include TemplatesSetupTeardown
+  include RenderTestCases
+
+  def setup
+    setup_view_paths_for(cache_templates = false)
+  end
+end
+
diff --git a/railties/environments/test.rb b/railties/environments/test.rb
index 496eb9572b..d6f80a4080 100644
--- a/railties/environments/test.rb
+++ b/railties/environments/test.rb
@@ -12,6 +12,7 @@ config.whiny_nils = true
 # Show full error reports and disable caching
 config.action_controller.consider_all_requests_local = true
 config.action_controller.perform_caching             = false
+config.action_view.cache_template_loading            = true
 
 # Disable request forgery protection in test environment
 config.action_controller.allow_forgery_protection    = false
diff --git a/railties/lib/initializer.rb b/railties/lib/initializer.rb
index c4c55a97eb..281b074e0a 100644
--- a/railties/lib/initializer.rb
+++ b/railties/lib/initializer.rb
@@ -369,8 +369,8 @@ Run `rake gems:install` to install the missing gems.
 
     def load_view_paths
       if configuration.frameworks.include?(:action_view)
-        ActionController::Base.view_paths.each { |path| path.load! } if configuration.frameworks.include?(:action_controller)
-        ActionMailer::Base.template_root.load! if configuration.frameworks.include?(:action_mailer)
+        ActionController::Base.view_paths.load! if configuration.frameworks.include?(:action_controller)
+        ActionMailer::Base.view_paths.load! if configuration.frameworks.include?(:action_mailer)
       end
     end
 
@@ -478,7 +478,7 @@ Run `rake gems:install` to install the missing gems.
     # set to use Configuration#view_path.
     def initialize_framework_views
       if configuration.frameworks.include?(:action_view)
-        view_path = ActionView::Template::Path.new(configuration.view_path)
+        view_path = ActionView::PathSet.type_cast(configuration.view_path)
         ActionMailer::Base.template_root ||= view_path if configuration.frameworks.include?(:action_mailer)
         ActionController::Base.view_paths = view_path if configuration.frameworks.include?(:action_controller) && ActionController::Base.view_paths.empty?
       end
diff --git a/railties/test/plugin_loader_test.rb b/railties/test/plugin_loader_test.rb
index 23b81ddbf6..59491fe99e 100644
--- a/railties/test/plugin_loader_test.rb
+++ b/railties/test/plugin_loader_test.rb
@@ -130,7 +130,7 @@ class TestPluginLoader < Test::Unit::TestCase
 
     @loader.send :add_engine_view_paths
     
-    assert_equal [ File.join(plugin_fixture_path('engines/engine'), 'app', 'views') ], ActionController::Base.view_paths
+    assert_equal [ File.join(plugin_fixture_path('engines/engine'), 'app', 'views').sub(/\A\.\//, '') ], ActionController::Base.view_paths
   end
 
   def test_should_add_plugin_load_paths_to_Dependencies_load_once_paths