Re: [PATCH v3 9/9] odb/transaction: add transaction interface to write packfiles

[Patrick Steinhardt <ps@pks.im>]

On Tue, Aug 11, 2026 at 12:54:15PM -0500, Justin Tobler wrote:
  			report_v2(commands, &unpack_status);
> diff --git a/object-file.c b/object-file.c
> index db63587f6d..a957bc126f 100644
> --- a/object-file.c
> +++ b/object-file.c
> @@ -1291,6 +1297,170 @@ static int odb_transaction_files_commit(struct odb_transaction *base)
>  	return 0;
>  }
>  
> +static const char *parse_pack_header(struct pack_header *hdr, int pack_fd)
> +{
> +	switch (read_pack_header(pack_fd, hdr)) {
> +	case PH_ERROR_EOF:
> +		return "eof before pack header was fully read";
> +
> +	case PH_ERROR_PACK_SIGNATURE:
> +		return "protocol error (pack signature mismatch detected)";
> +
> +	case PH_ERROR_PROTOCOL:
> +		return "protocol error (pack version unsupported)";
> +
> +	default:
> +		return "unknown error in parse_pack_header";
> +
> +	case 0:
> +		return NULL;
> +	}
> +}
> +
> +static void push_header_arg(struct strvec *args, struct pack_header *hdr)
> +{
> +	strvec_pushf(args, "--pack_header=%"PRIu32",%"PRIu32,
> +		     ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
> +}
> +
> +static unsigned int get_unpack_limit(struct repository *repo)
> +{
> +	unsigned int limit = 100;
> +
> +	repo_config_get_uint(repo, "transfer.unpacklimit", &limit);
> +	repo_config_get_uint(repo, "receive.unpacklimit", &limit);
> +
> +	return limit;
> +}

One thing I noticed just now: as the intention is that `write_pack()`
will be called for more use cases than only git-receive-pack(1) we'll
have to add a way to tell the callback what scenario they are running
in. I still think moving the unpack limit into the backend is sensible,
but now we're not givint it enough information.

Patrick