From: Jeff King <peff@peff.net>
Date: Wed, 14 Jan 2026 18:00:40 GMT
Subject: Re: [PATCH 5/6] fetch: utilize rejected ref error details
Message-ID: <20260114180040.GH885771@coredump.intra.peff.net>
In-Reply-To: <20260114-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v1-5-f5f8b173c501@gmail.com>

On Wed, Jan 14, 2026 at 04:40:46PM +0100, Karthik Nayak wrote:

> @@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
>  			"branches"), data->remote_name);
>  		data->conflict_msg_shown = true;
>  	} else {
> -		const char *reason = ref_transaction_error_msg(err);
> -
> -		error(_("fetching ref %s failed: %s"), refname, reason);
> +		if (details)
> +			error("%s", details);
> +		else
> +			error(_("fetching ref %s failed: %s"),
> +			      refname, ref_transaction_error_msg(err));
>  	}

OK, so here we're writing to stderr anyway, and now we'll just give the
more detailed data. Makes sense (though like Junio, I do wonder if the
existing message might provide more details in some cases).

BTW, I think there is still a related fallout for git-fetch. Even with
your patch, doing this:

  $ git fetch . v1.0.0:refs/heads/foo
  From .
   * [new tag]               v1.0.0     -> foo
  error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

will not put anything in the status table. Whereas in v2.50.0 and
earlier, we get:

  $ git.v2.50.0 fetch . v1.0.0:refs/heads/foo
  error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
  From .
   ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

Note the "!" and the "unable to update local ref" message in the status
table.

-Peff