Re: commit-message attack for extracting sensitive data from rewritten Git history

From: Johannes Sixt <j.sixt@viscovery.net>
Date: Apr 9, 2013, 06:03 UTC
Message-ID: <5163AF2C.2020107@viscovery.net>
In-Reply-To: <20130408215457.GB11227@sigill.intra.peff.net>

Am 4/8/2013 23:54, schrieb Jeff King:

Show 6 quoted lines

> Yeah, it would make sense for filter-branch to have a "--map-commit-ids"
> option or similar that does the update. At first I thought it might take
> two passes, but I don't think it is necessary, as long as we traverse
> the commits topologically (i.e., you cannot have mentioned X in a commit
> that is an ancestor of X, so you do not have to worry about mapping it
> until after it has been processed).

Topological traversal is not sufficient. Consider this history:

     o--A--o--
    /     /
 --o--B--o

If A mentions B (think of cherry-pick -x), then you must ensure that the branch containing B was traversed first.

-- Hannes