tests/test-merge8

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

# Test for changeset ba7c74081861
# (update dirstate correctly for non-branchmerge updates)
hg init a
cd a
echo a > a
hg add a
hg commit -m a
cd ..
hg clone a b
cd a
hg mv a b
hg commit -m move
echo b >> b
hg commit -m b
cd ../b
hg pull ../a
hg update