merge: fix a copy detection bug (issue672) When merging rev1 and rev2, we want to search for copies that happened in rev1 but not in rev2 and vice-versa. We were starting the search at rev1/rev2 and then going back, stopping as soon as we reached the revno of the ancestor, but that can miss some cases (see the new test-issue672). Now we calculate the revisions that are ancestors of rev1 or rev2 (but not both) and make sure the search doesn't stop too early. Simplified test provided by mpm, based on a test case provided by Edward Lee.

#!/bin/sh

# test that we don't interrupt the merge session if
# a file-level merge failed

hg init repo
cd repo

echo foo > foo
echo a > bar
hg ci -Am 'add foo' -d '0 0'

hg mv foo baz
echo b >> bar
echo quux > quux1
hg ci -Am 'mv foo baz' -d '0 0'

hg up -qC 0
echo >> foo
echo c >> bar
echo quux > quux2
hg ci -Am 'change foo' -d '0 0'

# test with the rename on the remote side
HGMERGE=false hg merge

# test with the rename on the local side
hg up -C 1
HGMERGE=false hg merge

true