discovery: introduce "stable slicing" methods
We introduce new code that leverage the stable sorting to slices a graph in a
way "stable" accross repository. This should allow us to use theses slices for
obsolescence markers discovery.
#!/bin/sh
# This file holds logic that is used in many tests.
# It can be called in a test like this:
# $ . "$TESTDIR/testlib/topic_setup.sh"
# Enable obsolete markers and enable extensions
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers,exchange
[extensions]
rebase=
EOF
echo "topic=$(echo $(dirname $TESTDIR))/hgext3rd/topic" >> $HGRCPATH