Merge pull request #265 from eileencodes/fix-perf-regression-in-rails-helper

Fix performance regression in Rails helper

Author: eileencodes

lib/sprockets/rails/helper.rb

@@ -21,7 +21,7 @@ def initialize(source)
       include Sprockets::Rails::Utils
 
       VIEW_ACCESSORS = [:assets_environment, :assets_manifest,
-                        :assets_precompile,
+                        :assets_precompile, :precompiled_assets,
                         :assets_prefix, :digest_assets, :debug_assets]
 
       def self.included(klass)
@@ -227,11 +227,6 @@ def lookup_debug_asset(path, options = {})
 
           asset
         end
-
-        # Internal: Generate a Set of all precompiled assets logical paths.
-        def precompiled_assets
-          @precompiled_assets ||= assets_manifest.find(assets_precompile || []).map(&:logical_path)
-        end
     end
   end
 end

lib/sprockets/rails/utils.rb

@@ -6,6 +6,11 @@ module Utils
       def using_sprockets4?
         Gem::Version.new(Sprockets::VERSION) >= Gem::Version.new('4.0.0')
       end
+
+      # Internal: Generate a Set of all precompiled assets logical paths.
+      def build_precompiled_list(manifest, assets)
+        manifest.find(assets || []).map(&:logical_path)
+      end
     end
   end
 end

lib/sprockets/railtie.rb

@@ -26,6 +26,9 @@ class Configuration
 
     # Returns Sprockets::Manifest for app config.
     attr_accessor :assets_manifest
+
+    # Returns array of already precompiled assets
+    attr_accessor :precompiled_assets
   end
 
   class Engine < Railtie
@@ -150,8 +153,11 @@ def self.build_manifest(app)
         app.routes.prepend do
           mount app.assets => config.assets.prefix
         end
+        app.assets_manifest = build_manifest(app)
+        app.precompiled_assets = build_precompiled_list(app.assets_manifest, config.assets.precompile)
+      else
+        app.assets_manifest = build_manifest(app)
       end
-      app.assets_manifest = build_manifest(app)
 
       ActionDispatch::Routing::RouteWrapper.class_eval do
         class_attribute :assets_prefix
@@ -176,6 +182,7 @@ def self.build_manifest(app)
 
         self.assets_environment = app.assets
         self.assets_manifest = app.assets_manifest
+        self.precompiled_assets = app.precompiled_assets
       end
     end
   end

test/test_helper.rb

@@ -25,6 +25,7 @@ def setup
     @view.assets_manifest    = @manifest
     @view.assets_prefix      = "/assets"
     @view.assets_precompile  = %w( manifest.js )
+    @view.precompiled_assets = @view.build_precompiled_list(@manifest, @view.assets_precompile)
     @view.request = ActionDispatch::Request.new({
       "rack.url_scheme" => "https"
     })
@@ -729,6 +730,7 @@ def test_stylesheet_link_tag_integrity
 class AssetUrlHelperLinksTarget < HelperTest
   def test_precompile_allows_links
     @view.assets_precompile = ["url.css"]
+    @view.precompiled_assets = @view.build_precompiled_list(@manifest, @view.assets_precompile)
     assert @view.asset_path("url.css")
     assert @view.asset_path("logo.png")