Error if asset alias is used from helper

Author: josh

lib/sprockets/rails/helper.rb

@@ -38,6 +38,15 @@ def initialize(bad_path, good_path, prefix)
         end
       end
 
+      class AssetAliasUsed < StandardError
+        def initialize(actual, expected)
+          msg = "Asset was linked to from an alias rather than its exact path. " +
+            "Alias resolving may not be available in production.\n" +
+            "Use #{expected.inspect} instead of #{actual.inspect}"
+          super(msg)
+        end
+      end
+
       if defined? ActionView::Helpers::AssetUrlHelper
         include ActionView::Helpers::AssetUrlHelper
         include ActionView::Helpers::AssetTagHelper
@@ -121,6 +130,10 @@ def asset_digest_path(path, options = {})
 
         if environment = assets_environment
           if asset = environment[path]
+            if self.raise_runtime_errors && path != asset.logical_path
+              raise AssetAliasUsed.new(path, asset.logical_path)
+            end
+
             return asset.digest_path
           end
         end

test/fixtures/bundle/index.js

@@ -0,0 +1 @@
+var jQuery;

test/fixtures/jquery/bower.json

@@ -0,0 +1,4 @@
+{
+  "name": "jquery",
+  "main": "./jquery.js"
+}

test/fixtures/jquery/jquery.js

@@ -0,0 +1 @@
+var jQuery;

test/test_helper.rb

@@ -699,4 +699,26 @@ def test_ignores_missing_dependencies
     end
     assert_includes paths, "missing.css.erb"
   end
+
+  def test_asset_path_with_index_requires_exact_logical_path
+    Sprockets::Rails::Helper.raise_runtime_errors = true
+    Sprockets::Rails::Helper.precompile = ["bundle.js"]
+
+    assert @view.asset_path("bundle.js")
+
+    assert_raises(Sprockets::Rails::Helper::AssetAliasUsed) do
+      assert @view.asset_path("bundle/index.js")
+    end
+  end
+
+  def test_asset_path_with_bower_requires_exact_logical_path
+    Sprockets::Rails::Helper.raise_runtime_errors = true
+    Sprockets::Rails::Helper.precompile = ["jquery/jquery.js"]
+
+    assert @view.asset_path("jquery/jquery.js")
+
+    assert_raises(Sprockets::Rails::Helper::AssetAliasUsed) do
+      assert @view.asset_path("jquery.js")
+    end
+  end
 end