git clone of empty repositories doesn't preserve hash

From: Adam Majer <adamm@zombino.com>
Date: Apr 5, 2023, 10:28 UTC
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

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.