Mercurial error: repository is unrelated

Question

I\'ve just started with Mercurial, I have a \'central\' repository on Bitbucket which I cloned onto one machine and made changes and committed and pushed. I then cloned from

Answer 1

I would like to share knowledge about Mercurial internals.

Repositories unrelated when they have no any same revisions.

Corresponding piece you can find in 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 is a list of roots of common parts in both local/remote repositories.

You always may know how repositories are different by:

$ hg in $REMOTE
$ hg out $REMOTE

You always may checks roots of both (after cloning both locally):

$ hg -R $ONE log -r "roots(all())"
$ hg -R $TWO log -r "roots(all())"

if output from above commands doesn't share IDs - those repositories are unrelated. Due to hash properties it is very impossible that roots be equal accidentally. 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.

Having this info I believe any Devs be able to troubleshoot error: repository is unrelated.

See also Mercurial repository identification

Thanks for attention, good hacking!