Fix mismatching variable names when using an underscore

The ERBTracker template digest helper class was using a regex to match
render calls and it was incorrectly not matching against variables with
underscores in the name. This caused it to use the wrong regex match data
to populate the template dependency. Because underscore is a valid
character for a variable, this fixes the ERBTracker to match it properly.

actionpack/lib/action_view/dependency_tracker.rb

@@ -74,7 +74,7 @@ def render_dependencies
             # render(@topic)         => render("topics/topic")
             # render(topics)         => render("topics/topic")
             # render(message.topics) => render("topics/topic")
-            collect { |name| name.sub(/\A@?([a-z]+\.)*([a-z_]+)\z/) { "#{$2.pluralize}/#{$2.singularize}" } }.
+            collect { |name| name.sub(/\A@?([a-z_]+\.)*([a-z_]+)\z/) { "#{$2.pluralize}/#{$2.singularize}" } }.
 
             # render("headline") => render("message/headline")
             collect { |name| name.include?("/") ? name : "#{directory}/#{name}" }.

actionpack/test/template/dependency_tracker_test.rb

@@ -1,24 +1,24 @@
 require 'abstract_unit'
 require 'action_view/dependency_tracker'
 
-class DependencyTrackerTest < ActionView::TestCase
-  Neckbeard = lambda {|template| template.source }
-  Bowtie = lambda {|template| template.source }
-
-  class NeckbeardTracker
-    def self.call(name, template)
-      ["foo/#{name}"]
-    end
+class NeckbeardTracker
+  def self.call(name, template)
+    ["foo/#{name}"]
   end
+end
 
-  class FakeTemplate
-    attr_reader :source, :handler
+class FakeTemplate
+  attr_reader :source, :handler
 
-    def initialize(source, handler = Neckbeard)
-      @source, @handler = source, handler
-    end
+  def initialize(source, handler = Neckbeard)
+    @source, @handler = source, handler
   end
+end
+
+Neckbeard = lambda {|template| template.source }
+Bowtie = lambda {|template| template.source }
 
+class DependencyTrackerTest < ActionView::TestCase
   def tracker
     ActionView::DependencyTracker
   end
@@ -44,3 +44,31 @@ def test_returns_empty_array_if_no_tracker_is_found
     assert_equal [], dependencies
   end
 end
+
+class ERBTrackerTest < MiniTest::Unit::TestCase
+  def make_tracker(name, template)
+    ActionView::DependencyTracker::ERBTracker.new(name, template)
+  end
+
+  def test_dependency_of_erb_template_with_number_in_filename
+    template = FakeTemplate.new("<%# render 'messages/message123' %>", :erb)
+    tracker = make_tracker('messages/_message123', template)
+
+    assert_equal ["messages/message123"], tracker.dependencies
+  end
+
+  def test_finds_dependency_in_correct_directory
+    template = FakeTemplate.new("<%# render(message.topic) %>", :erb)
+    tracker = make_tracker('messages/_message', template)
+
+    assert_equal ["topics/topic"], tracker.dependencies
+  end
+
+  def test_finds_dependency_in_correct_directory_with_underscore
+    template = FakeTemplate.new("<%# render(message_type.messages) %>", :erb)
+    tracker = make_tracker('message_types/_message_type', template)
+
+    assert_equal ["messages/message"], tracker.dependencies
+  end
+end
+