hgweb: don't raise an exception when displying empty repos The nullid node claims it's in the default branch, but the branch dict is empty. This fixes the main symptom from issue696, but we may want to set branchtags()['default'] = nullid somewhere for empty repos.

#!/bin/sh

hg init
mkfifo p

hg serve --stdio < p &
P=$!
(echo lock; echo addchangegroup; sleep 5) > p &
Q=$!
sleep 3
kill -HUP $P
wait
echo .hg/* .hg/store/*