From: Jeff King <peff@peff.net>
To: "Оля Тележная" <olyatelezhnaya@gmail.com>
Cc: git <git@vger.kernel.org>, Junio C Hamano <gitster@pobox.com>,
Christian Couder <christian.couder@gmail.com>
Subject: Re: ref-filter: how to improve the code
Date: Thu, 1 Mar 2018 10:04:52 -0500 [thread overview]
Message-ID: <20180301150451.GC24907@sigill.intra.peff.net> (raw)
In-Reply-To: <CAL21BmkVq4j=hgupPvZqigSGQ-=rgwKVvzTD_X-_Z__8qmeKJg@mail.gmail.com>
On Thu, Mar 01, 2018 at 02:17:09PM +0300, Оля Тележная wrote:
> >> I tried to replace all die("...") with `return error("...")` and
> >> finally exit(), but actual problem is that we print "error:..."
> >> instead of "fatal:...", and it looks funny.
> >
> > If you do that, then format_ref_array_item() is still going to print
> > things, even if it doesn't die(). But for "cat-file --batch", we usually
> > do not print errors at all, but instead just say "... missing" (although
> > it depends on the error; syntactic errors in the format string would
> > still cause us to write to stderr).
>
> Not sure if you catch my idea. format_ref_array_item() will not print
> anything, it will just return an error code. And if there was an error
> - we will print it in show_ref_array_item() (or go back to cat-file
> and print what we want).
OK, I think I misunderstood. It seems like there are three possible
strategies on the table:
- low-level functions call error() and return -1, that gets passed up
through mid-level functions like format_ref_array_item(), and then
higher-level functions like show_ref_array_item() act on the error
code and call die(). The user sees something like:
error: unable to parse object 1234abcd
fatal: unable to format object
- low-level functions return a numeric error code, which is then
formatted by higher-level functions like show_ref_array_item() to
produce a specific message
- low-level functions stuff an error code into a strbuf and return -1,
and then higher-level functions like show_ref_array_item() will feed
that message to die("%s", err.buf).
I think the first one, besides changing the output, is going to produce
error() messages even for cases where we're calling
format_ref_array_item() directly, because error() writes its output
immediately.
The second is a pain in practice, because it doubles the work: you have
to come up with a list of error codes, and then translate it them into
strings. And there's no room to mention variable strings (like the name
of the object).
So I think the third is really the only viable option.
-Peff
prev parent reply other threads:[~2018-03-01 15:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-25 18:28 ref-filter: how to improve the code Оля Тележная
2018-02-28 13:25 ` Jeff King
2018-03-01 11:17 ` Оля Тележная
2018-03-01 15:04 ` Jeff King [this message]
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