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

[Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>]

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

> Matthieu Moy <Matthieu.Moy@grenoble-inp.fr> writes:
>
>> 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.
>
> I agree that _this_ part is easy to understand when written that
> way.  But then shouldn't there be a blanket "The caller is here only
> to report an error, but all the previous code didn't find any error,
> so there is something wrong" check much later in the code before it
> returns a success?  Or am I being too paranoid?

Currently, there's no problem if get_sha1_with_context_1 returns without
dying, because the caller does:

	if (!(arg[0] == ':' && !isalnum(arg[1])))
		/* try a detailed diagnostic ... */
		get_sha1_with_mode_1(arg, sha1, &mode, 1, prefix);

	/* ... or fall back the most general message. */
	die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
	    "Use '--' to separate paths from revisions", arg);

If we failed to give a nice diagnosis, we give the generic error
message.

We could add this check within get_sha1_with_context_1 to simplify the
task of the caller, but that would require adding it before each
"return" statement, which I think is overkill.

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