Is it possible to preserve the commit history of a tree of files as it
moves out of one repository and into another?
I have two use-cases to consider: one long-term, one short-term.
Long-term: I am considering trying to move Pod-Html from its current
location within ext/ in the Perl 5 core distribution to cpan/, i.e.,
have CPAN be upstream. That really can't be done right away because,
as the subject line of a META ticket opened by rjbs indicates, "Pod-Html
is a mess." It's code is poorly structured. Its test coverage is
unsatisfactory. It has many RTs open. It would be shameful to put it
out on CPAN in its current state. I've made one sustained attempt at a
cleanup; I'm now considering another. But once it's out on CPAN and
its principal repository is presumably on github.com, I would like the
code to retain as much of its history from the Perl 5 repository as
How do we do that?
Short-term: In order to do a thorough cleanup on Pod-Html, I want to be
free to poke and prod it to my heart's content. Among other things,
that's means constant checking of the test coverage with Devel-Cover.
My preference would be to do that in a repo other than Perl 5, but if I
did so I would want my changes to go back into Perl 5's Pod-Html so that
people could get used to it before we moved it to CPAN. And I would
want to preserve the commit history in lib/Pod/Htmlm.pm and the test
suite throughout that round trip.
How do I do that?
Thank you very much.
 Personally, I don't think Pod-Html needs to be distributed with core
at all. But since I know there will be differences of opinion about
this and since moving it to upstream CPAN is a prerequisite to
expulsion, moving it to cpan/ is all we need to discuss for now.
 At the DuckDuckGo hackathon in Paoli in June/July 2012, rjbs
suggested I look at Pod-Html and start cleaning it up so that it could
eventually go to CPAN. I spent about six weeks working on it. I myself
had not used Pod-Html in more than a decade. I didn't know anyone who
did. So I ran out of motivation. But since I've recently met one
person who does use it, I'm considering resuming my efforts.
 In my 2012 attempts, I moved the existing codebase into a typical
CPAN structure, then committed that to a new git repo, losing the
existing history in the process. I knew much less about git back then.
I discussed that with rjbs and he said we could worry about the commit
history later. If I embark on this project again, I'd like to get it
right from the git-go.