Allow cache to be temporarily disabled through lookup_context.

actionpack/lib/action_view/lookup_context.rb

@@ -61,6 +61,7 @@ module ActionView
     def initialize(view_paths, details = {})
       @details, @details_key = { :handlers => default_handlers }, nil
       @frozen_formats, @skip_default_locale = false, false
+      @cache = details.key?(:cache) ? details.delete(:cache) : true
 
       self.view_paths = view_paths
       self.registered_detail_setters.each do |key, setter|
@@ -130,10 +131,20 @@ module ActionView
     end
 
     module Details
+      attr_accessor :cache
+
       # Calculate the details key. Remove the handlers from calculation to improve performance
       # since the user cannot modify it explicitly.
       def details_key #:nodoc:
-        @details_key ||= DetailsKey.get(@details)
+        @details_key ||= DetailsKey.get(@details) if @cache
+      end
+
+      # Temporary skip passing the details_key forward.
+      def disable_cache
+        old_value, @cache = @cache, false
+        yield
+      ensure
+        @cache = old_value
       end
 
       # Freeze the current formats in the lookup context. By freezing them, you are guaranteeing

actionpack/lib/action_view/template.rb

@@ -286,7 +286,9 @@ module ActionView
         pieces  = @virtual_path.split("/")
         name    = pieces.pop
         partial = name.sub!(/^_/, "")
-        view.find_template(name, pieces.join, partial || false, ["unlikely_local_key"])
+        view.lookup_context.disable_cache do
+          view.find_template(name, pieces.join, partial || false, @locals)
+        end
       end
 
       def method_name

actionpack/lib/action_view/testing/resolvers.rb

@@ -16,16 +16,18 @@ module ActionView #:nodoc:
     private
 
     def query(path, exts, formats)
-      query = Regexp.escape(path)
+      query = ""
       exts.each do |ext|
         query << '(' << ext.map {|e| e && Regexp.escape(".#{e}") }.join('|') << '|)'
       end
+      query = /^(#{Regexp.escape(path)})#{query}$/
 
       templates = []
-      @hash.select { |k,v| k =~ /^#{query}$/ }.each do |_path, source|
+      @hash.each do |_path, source|
+        next unless _path =~ query
         handler, format = extract_handler_and_format(_path, formats)
         templates << Template.new(source, _path, handler,
-          :virtual_path => _path, :format => format)
+          :virtual_path => $1, :format => format)
       end
 
       templates.sort_by {|t| -t.identifier.match(/^#{query}$/).captures.reject(&:blank?).size }

actionpack/test/controller/new_base/render_template_test.rb

@@ -11,7 +11,8 @@ module RenderTemplate
       "with_raw.html.erb"        => "Hello <%=raw '<strong>this is raw</strong>' %>",
       "test/with_json.html.erb"  => "<%= render :template => 'test/with_json.json' %>",
       "test/with_json.json.erb"  => "<%= render :template => 'test/final' %>",
-      "test/final.json.erb"      => "{ final: json }"
+      "test/final.json.erb"      => "{ final: json }",
+      "test/with_error.html.erb" => "<%= idontexist %>"
     )]
 
     def index
@@ -49,6 +50,10 @@ module RenderTemplate
     def with_raw
       render :template => "with_raw"
     end
+
+    def with_error
+      render :template => "test/with_error"
+    end
   end
 
   class TestWithoutLayout < Rack::TestCase
@@ -101,6 +106,12 @@ module RenderTemplate
       assert_content_type "text/html; charset=utf-8"
       assert_response "{ final: json }"
     end
+
+    test "rendering a template with error properly exceprts the code" do
+      get :with_error
+      assert_status 500
+      assert_match "undefined local variable or method `idontexist'", response.body
+    end
   end
 
   class WithLayoutController < ::ApplicationController

actionpack/test/template/lookup_context_test.rb

@@ -163,4 +163,25 @@ class LookupContextTest < ActiveSupport::TestCase
     template = @lookup_context.find("foo", "test", true)
     assert_equal "Bar", template.source
   end
+
+  test "can disable the cache on demand" do
+    @lookup_context.view_paths = ActionView::FixtureResolver.new("test/_foo.erb" => "Foo")
+    old_template = @lookup_context.find("foo", "test", true)
+
+    template = @lookup_context.find("foo", "test", true)
+    assert_equal template, old_template
+
+    assert @lookup_context.cache
+    template = @lookup_context.disable_cache do
+      assert !@lookup_context.cache
+      @lookup_context.find("foo", "test", true)
+    end
+    assert @lookup_context.cache
+
+    assert_not_equal template, old_template
+  end
+
+  test "can have cache disabled on initialization" do
+    assert !ActionView::LookupContext.new(FIXTURE_LOAD_PATH, :cache => false).cache
+  end
 end