Use wsgi.url_scheme instead of ad-hoc CGI checks. Instead of each place in hgweb_mod that needs to check for SSL or get the protocol scheme (http vs. https) doing it ad-hoc, make them just look at the wsgi.url_scheme which because of previous patches is now always set correctly.

#!/bin/sh

hg init
touch a
hg add a
hg ci -m "a" -d "1000000 0"

echo 123 > b
hg add b
hg diff --nodates

hg diff --nodates -r tip

echo foo > a
hg diff --nodates

hg diff -r ""
hg diff -r tip -r ""

true