tests/readlink.py

amend: allow amend of non-head when obsolete is enabled

Obsolescence marker can represent this situation just fine. The old
version is marked as precursor of the new changeset. All its
descendants become "unstable".

If obsolescence is not enabled we keep the current behavior of
aborting. This new behavior only applies when obsolete is
enabled and is subject to future discussion and changes.

#!/usr/bin/env python

import errno, os, sys

for f in sys.argv[1:]:
    try:
        print f, '->', os.readlink(f)
    except OSError, err:
        if err.errno != errno.EINVAL:
            raise
        print f, 'not a symlink'

sys.exit(0)