Subject: Re: [PATCH] show-index: warn when falling back to SHA-1 outside a repository

From: Shreyansh Paliwal <[email-masked]>
Date: Fri, 30 Jan 2026 14:34:53 +0530

> On 2026-01-29 at 15:36:55, Shreyansh Paliwal wrote:
> >	/*
> >	 * Fallback to SHA1 if we are running outside of a repository.
> >	 *
> > -	 * TODO: Figure out and implement a way to detect the hash algorithm in use by the
> > -	 *       the index file passed in and use that instead.
> > +	 * TODO: If a future implementation of index file version encodes the hash
> > +	 *       algorithm in its header, enable show-index to infer it from the
> > +	 *       header rather than relying on repository context or a default fallback.
> >	 */
> > -	if (!the_hash_algo)
> > +	if (!the_hash_algo) {
> > +		warning(_("assuming SHA-1; use --object-format to override"));
> >		repo_set_hash_algo(the_repository, GIT_HASH_DEFAULT);
> 
> If we're going to start producing a warning, can we also learn a
> `--quiet` option to silence it?

Hi,

That is a good point.
However, the warning is only shown for a particular usecase: when 
'git show-index' is run outside of a repository and --object-format
is not specified. Given that narrow scope, I’m wondering whether
adding a dedicated --quiet option for only this warning would be worthwhile.

Let me know what you think :)

Best,
Shreyansh