performance: do not stat() things when not required
Ignore unknown files if we don't need them (eg in hg diff).
It slows things down a little bit for big trees (kernel repo), since _join()
is called for each file instead of for each directory.
fix issue567
#!/bin/sh
hg init 1
echo '[ui]' >> 1/.hg/hgrc
echo 'timeout = 10' >> 1/.hg/hgrc
echo foo > 1/foo
hg --cwd 1 ci -A -m foo
hg clone 1 2
hg clone 2 3
echo '[hooks]' >> 2/.hg/hgrc
echo 'changegroup.push = hg push -qf ../1' >> 2/.hg/hgrc
echo bar >> 3/foo
hg --cwd 3 ci -m bar
hg --cwd 3 push ../2