This is a work based on #2701, Before this patch, it is either fully external, or fully internal (and DokuWiki's auth cookie mechanism is used in auth_login()). I believe we should provide plugin developers with a third state as out-put. Semantically $auth->trustExternal() === null to delegate auth flow back to DokuWiki makes sense to me - like no external auth result is returned, so we need to run internal auth flow.
Co-Authored-By: paweljasinski <paweljasinski@users.noreply.github.com>
