Re: Round-tripping fast-export/import changes commit hashes

[anatoly techtonik <techtonik@gmail.com>]

On Thu, Mar 4, 2021 at 3:56 AM Junio C Hamano <gitster@pobox.com> wrote:
>
> Johannes Sixt <j6t@kdbg.org> writes:
>
> > Am 02.03.21 um 22:52 schrieb anatoly techtonik:
> >> For my use case, where I just need to attach another branch in
> >> time without altering original commits in any way, `reposurgeon`
> >> can not be used.
> >
> > What do you mean by "attach another branch in time"? Because if you
> > really do not want to alter original commits in any way, perhaps you
> > only want `git fetch /the/other/repository master:the-other-one-s-master`?
>
> Yeah, I had the same impression.  If a bit-for-bit identical copy of
> the original history is needed, then fetching from the original
> repository (either directly or via a bundle) would be a much simpler
> and performant way.

The goal is to have an editable stream, which, if left without edits, would
be bit-by-bit identical, so that external tools like `reposurgeon` could
operate on that stream and be audited.

Right now, because the repository
https://github.com/simons-public/protonfixes contains a signed commit
right from the start, the simple fast-export and fast-import with git itself
fails the check.

I understand that patching `git` to add `--complete` to fast-import is
realistically beyond my coding abilities, and my only option is to parse
the binary stream produced by `git cat-file --batch`, which I also won't
be able to do without specification.

P.S. I am resurrecting the old thread, because my problem with editing
the history of the repository with an external tool still can not be solved.
-- 
anatoly t.