2 files changed, 15 insertions, 14 deletions
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
index fc0cca28b9..52eb43a1cd 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
@@ -71,9 +71,21 @@ module ActionView
             if sources.first == :all
               collect_asset_files(custom_dir, ('**' if recursive), "*.#{extension}")
             else
-              sources.collect do |source|
-                determine_source(source, expansions)
-              end.flatten
+              sources.inject([]) do |list, source|
+                determined_source = determine_source(source, expansions)
+                update_source_list(list, determined_source)
+              end
+            end
+          end
+
+          def update_source_list(list, source)
+            case source
+            when String
+              list.delete(source)
+              list << source
+            when Array
+              updated_sources = source - list
+              list.concat(updated_sources)
             end
           end
 
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
index 4781832711..b9126af944 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
@@ -42,17 +42,6 @@ module ActionView
             end
           end
 
-          def update_source_list(list, source)
-            case source
-            when String
-              list.delete(source)
-              list << source
-            when Array
-              updated_sources = source - list
-              list.concat(updated_sources)
-            end
-          end
-
           def add_application_js(expanded_sources, sources)
             if sources.include?(:defaults) && File.exist?(File.join(custom_dir, "application.#{extension}"))
               expanded_sources.delete('application')