From d70166fd3ea37368a5327f3e838d0bf9902c5e4f Mon Sep 17 00:00:00 2001
From: Christos Zisopoulos <christos@42linesofcode.com>
Date: Fri, 29 May 2009 17:39:45 +0200
Subject: [PATCH] Fix zero length stylesheet cache files bug in case of missing CSS files

---
 .../lib/action_view/helpers/asset_tag_helper.rb    |    2 +
 actionpack/test/template/asset_tag_helper_test.rb  |   30 ++++++++++++++++++++
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index a32beb6..873c0a7 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -657,6 +657,8 @@ module ActionView
         end
 
         def write_asset_file_contents(joined_asset_path, asset_paths)
+          asset_paths = asset_paths.select {|path| File.readable?(asset_file_path(path))}
+
           FileUtils.mkdir_p(File.dirname(joined_asset_path))
           File.open(joined_asset_path, "w+") { |cache| cache.write(join_asset_file_contents(asset_paths)) }
 
diff --git a/actionpack/test/template/asset_tag_helper_test.rb b/actionpack/test/template/asset_tag_helper_test.rb
index 2f5bccb..83a8172 100644
--- a/actionpack/test/template/asset_tag_helper_test.rb
+++ b/actionpack/test/template/asset_tag_helper_test.rb
@@ -558,6 +558,36 @@ class AssetTagHelperTest < ActionView::TestCase
     FileUtils.rm_f(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'money.css'))
   end
 
+  def test_caching_stylesheet_link_tag_when_caching_on_and_missing_css_file
+    ENV["RAILS_ASSET_ID"] = ""
+    ActionController::Base.asset_host = 'http://a0.example.com'
+    ActionController::Base.perform_caching = true
+
+    assert_dom_equal(
+      %(<link href="http://a0.example.com/stylesheets/all.css" media="screen" rel="stylesheet" type="text/css" />),
+      stylesheet_link_tag('bank', 'robber', 'missing_security_guard', :cache => true)
+    )
+
+    files_to_be_joined = Dir["#{ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR}/{bank,robber,missing_security_guard}.css"]
+
+    expected_mtime = files_to_be_joined.map { |p| File.mtime(p) }.max
+    assert_equal expected_mtime, File.mtime(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'all.css'))
+
+    bytes_added_by_join = "\n\n".size * (files_to_be_joined.size - 1)
+    expected_size = files_to_be_joined.sum { |p| File.size(p) } + bytes_added_by_join
+    assert_equal expected_size, File.size(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'all.css'))
+
+    assert_dom_equal(
+      %(<link href="http://a0.example.com/stylesheets/money.css" media="screen" rel="stylesheet" type="text/css" />),
+      stylesheet_link_tag('bank', 'robber', 'missing_security_guard', :cache => "money")
+    )
+
+    assert File.exist?(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'money.css'))
+  ensure
+    FileUtils.rm_f(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'all.css'))
+    FileUtils.rm_f(File.join(ActionView::Helpers::AssetTagHelper::STYLESHEETS_DIR, 'money.css'))
+  end
+  
   def test_caching_stylesheet_link_tag_when_caching_on_with_proc_asset_host
     ENV["RAILS_ASSET_ID"] = ""
     ActionController::Base.asset_host = Proc.new { |source| "http://a#{source.length}.example.com" }
-- 
1.6.1