evolve: run in a single transaction
This speeds up `hg evolve --all` of a stack of 24 commits in the hg
repo from 11.5s to 3.7s (3x). As can be seen in the tests, it also
avoid some warnings about transiently unstable commits.
# setup config and various utility to test new heads checks on push
. $TESTDIR/testlib/common.sh
cat >> $HGRCPATH <<EOF
[ui]
# simpler log output
logtemplate ="{node|short} ({phase}): {desc}\n"
[phases]
# non publishing server
publish=False
[extensions]
# we need to strip some changeset for some test cases
strip=
evolve=
EOF
setuprepos() {
echo creating basic server and client repo
hg init server
cd server
mkcommit root
hg phase --public .
mkcommit A0
cd ..
hg clone server client
}