Re: [PATCH v2 13/13] commit-graph: specify OID version for SHA-256

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 16, 2018, 02:00 UTC
Message-ID: <xmqqk1mi4pn0.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20181015021900.1030041-14-sandals@crustytoothpaste.net>

"brian m. carlson" <sandals@crustytoothpaste.net> writes:

Show 27 quoted lines

> Since the commit-graph code wants to serialize the hash algorithm into
> the data store, specify a version number for each supported algorithm.
> Note that we don't use the values of the constants themselves, as they
> are internal and could change in the future.
>
> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> ---
>  commit-graph.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/commit-graph.c b/commit-graph.c
> index 7a28fbb03f..e587c21bb6 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -45,7 +45,14 @@ char *get_commit_graph_filename(const char *obj_dir)
>  
>  static uint8_t oid_version(void)
>  {
> -	return 1;
> +	switch (hash_algo_by_ptr(the_hash_algo)) {
> +		case GIT_HASH_SHA1:
> +			return 1;
> +		case GIT_HASH_SHA256:
> +			return 2;
> +		default:
> +			BUG("unknown hash algorithm");
> +	}

Style: align switch/case.

Shouldn't this be just using GIT_HASH_* constants instead? Are we expecting that it would be benefitial to allow more than one "oid version" even within a same GIT_HASH_*?

>  }
>  
>  static struct commit_graph *alloc_commit_graph(void)