If the first component of a path in a repository equals one of the strings above, the wrong route gets selected in the case of links without @repository_id@ (as they are generated from wiki @source:@ links to the default repository of a project) and the intended action is mistaken for the @repository_id@ parameter. Attached is a patch to the repository routing test illustrating the issue.

I would suggest to change repository#identifier_param to always return an identifier (see second patch) and remove the repository routes without repository_id (rows 280ff in current config/routes.rb).