tests/helpers-testrepo.sh

update: fix bare --clean to work on new branch (issue5003) (BC)

Before this commit bare update --clean on newly created branch
updates to the parent commit, even if there are later commits
on the parent commit's branch. Update to the latest head on the
parent commit's branch instead.

This seems reasonable as clean should discard uncommited changes,
branch is one of them.

# The test-repo is a live hg repository which may have evolution
# markers created, e.g. when a ~/.hgrc enabled evolution.
#
# Tests are run using a custom HGRCPATH, which do not
# enable evolution markers by default.
#
# If test-repo includes evolution markers, and we do not
# enable evolution markers, hg will occasionally complain
# when it notices them, which disrupts tests resulting in
# sporadic failures.
#
# Since we aren't performing any write operations on the
# test-repo, there's no harm in telling hg that we support
# evolution markers, which is what the following lines
# for the hgrc file do:
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers
EOF