Re: [PATCH] tag: fix sign_buffer() call to create a signed tag

[Jeff King <peff@peff.net>]

On Wed, Feb 07, 2024 at 09:29:00PM -0800, Junio C Hamano wrote:

> Junio C Hamano <gitster@pobox.com> writes:
> 
> > We could do belt and suspenders by tightening the other callers to
> > only expect negative for errors (but then what should they do when
> > they receive non-zero positive?  Should they BUG() out???) while
> > teaching sign_buffer_ssh() that our convention is to return negative
> > for an error, of course, but I am not sure if it that is worth it.
> 
> Actually, we could loosen the caller(s) while tightening the
> callee(s), which is the more usual approach we would take in a
> situation like this.  Here is what I am tempted to pile on top of
> the patch.
> 
> ----- >8 --------- >8 --------- >8 --------- >8 --------- >8 -----
> Subject: [PATCH] ssh signing: signal an error with a negative return value
> 
> The other backend for the sign_buffer() function followed our usual
> "an error is signalled with a negative return" convention, but the
> SSH signer did not.  Even though we already fixed the caller that
> assumed only a negative return value is an error, tighten the callee
> to signal an error with a negative return as well.  This way, the
> callees will be strict on what they produce, while the callers will
> be lenient in what they accept.

Yeah, I think that would possibly lead to fewer surprises and is worth
doing.

-Peff