Re: [PATCH 1/2] sha1_name: don't trigger detailed diagnosis for file arguments

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: Jun 18, 2012, 17:42 UTC
Message-ID: <vpqpq8wpled.fsf@bauges.imag.fr>
In-Reply-To: <7vehpc4jpw.fsf@alter.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> writes:

Show 13 quoted lines

> I am not so sure about that.  The "only-to-die" caller is not even
> expecting that the call to this codepath would successfully return.
>
> Or at least, it shouldn't.
>
> So it might not be a bad idea to actually catch this as a
> programming error and do
>
> 	if (only_to_die) {
>         	if (!ret)
>                 	die("BUG");
> 		diagnose_invalid_sha1_path(...);
> 	}

I disagree.

The only-to-die caller can expect that get_sha1_with_context_1 never returns when called with only-to-die, but it's a stronger assumption to expect that this particular place will trigger the failure.

In this case, the assumption is correct because there's a "return ret;" a bit later in the code, but I don't think we should have to look at this to check the correctness of the code (for example, if something like "if (ret) try_some_fallback_method();" is later added before "return ret;", then the assumption would become false).

My version reads as

  try something;
  if (it failed && I'm only here to report an error)
          report_error();

which I find easier to understand.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/