Mercurial repository identification

Question

I need to be able to uniquely identify a Mercurial repository and have that identifier placed in a file that is included when cloned. If I can put the identifier in a file i

Answer 1

error: repository is unrelated message come from mercurial/treediscovery.py:

base = list(base)
if base == [nullid]:
    if force:
        repo.ui.warn(_("warning: repository is unrelated\n"))
    else:
        raise util.Abort(_("repository is unrelated"))

base variable store last common parts of two repositories. By giving this idea of push/pull checks we may assume that repositories are related if they have common roots, so check hashes from command:

$ hg log -r "roots(all())"

For unknown to me reason hg log -r 0 always shown same root, but you may have situation that FIRST_REPO hold SECOND_REPO history, but obviously 0 revs of SECOND_REPO different from FIRST_REPO but Mercurial check is passed.

You may not trick roots checking by carefully crafting repositories because building two repositories looks like these (with common parts but different roots):

0 <--- SHA-256-XXX <--- SHA-256-YYY <--- SHA-256-ZZZ
0 <--- SHA-256-YYY <--- SHA-256-ZZZ

impossible because that mean you reverse SHA-256 as each subsequent hash depends on previous values.