patch.py: re-add the ability to use an external patch program This is now invoked by default only if ui.patch is set. Otherwise, we use our built-in patch. If that fails because it can't find any valid hunks, we'll fall back to trying the external patch command.

#!/bin/sh

set -e

mkdir test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m "1"
hg verify

hg clone . ../branch
cd ../branch
hg co
echo bar>>foo
hg commit -m "2"

cd ../test
hg pull ../branch
hg verify
hg co
cat foo
hg manifest --debug