url: always access req._tunnel_host The getattr() was there to handle Python versions before 2.6, which lacked this attribute. We /might/ be able to further delete some code here. However, the behavior here is extremely hard to follow because large parts of this code duplicate code from the Python standard library and it is difficult to understand what is actually needed. Differential Revision: https://phab.mercurial-scm.org/D5950