If a file is in the load path, require it without its full path (in more places)

activesupport/lib/active_support/dependencies.rb

@@ -388,8 +388,13 @@ def loadable_constants_for_path(path, bases = autoload_paths)
     end
 
     # Search for a file in autoload_paths matching the provided suffix.
-    def search_for_file(path_suffix)
-      path_suffix = path_suffix.sub(/(\.rb)?$/, ".rb")
+    def search_for_file(file)
+      path_suffix = file.sub(/(\.rb)?$/, ".rb")
+
+      $:.each do |root|
+        path = File.join(root, path_suffix)
+        return file if File.file?(path)
+      end
 
       autoload_paths.each do |root|
         path = File.join(root, path_suffix)