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

From: Junio C Hamano <[email-masked]>
Date: Wed, 07 Feb 2024 21:29:00 -0800

Junio C Hamano <[email-masked]> 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.

Signed-off-by: Junio C Hamano <[email-masked]>
---
 gpg-interface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gpg-interface.c b/gpg-interface.c
index 48f43c5a21..e19a69c400 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -1088,7 +1088,7 @@ static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
 		if (strstr(signer_stderr.buf, "usage:"))
 			error(_("ssh-keygen -Y sign is needed for ssh signing (available in openssh version 8.2p1+)"));
 
-		error("%s", signer_stderr.buf);
+		ret = error("%s", signer_stderr.buf);
 		goto out;
 	}
 
-- 
2.43.0-561-g235986be82