From: Adam Majer <adamm@zombino.com>
Date: Wed, 05 Apr 2023 10:28:12 GMT
Subject: git clone of empty repositories doesn't preserve hash
Message-ID: <e7a8957e-6251-39f1-5109-87d4dd382e81@zombino.com>

Hi all,

I've noticed while adding support for sha256 repositories for Gitea that,

git init --bare --object-format=sha256 a
git clone a b

Then the repository b is initialized as default hash, so sha1. It seems 
that receive-pack will list the null OID in the header if there are no 
refs available, but the upload-pack doesn't list anything and hence the 
header with capabilities and the hash function is missing

git receive-pack a
git upload-pack a

What is the right approach here? Could upload-pack send a NULL OID 
followed by header info that is then used by clone?

There is a workaround to specify the hash via GIT_DEFAULT_HASH. Not 
ideal though.

Thanks,
Adam