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From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>,
	Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org,
	Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Subject: Re: [PATCH 1/1] vreportf(): avoid buffered write in favor of unbuffered one
Date: Tue, 29 Oct 2019 21:09:14 +0100 (CET)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.1910292101300.46@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20191029143246.GA3683@sigill.intra.peff.net>

Hi Peff,

On Tue, 29 Oct 2019, Jeff King wrote:

> On Tue, Oct 29, 2019 at 03:13:39PM +0100, Johannes Schindelin wrote:
> >
> > > I'd disagree here. Any caller sending an arbitrarily-large prefix
> > > is holding it wrong, and we'd probably want to know as soon as
> > > possible (and a BUG() is our best bet there).
> >
> > How about truncating already inside the prefix, then? It would miss
> > the entire error message... but at least it would print
> > _something_...
>
> Yeah, that might be OK. Hopefully missing the whole rest of the error
> message would cause some tests to fail.

I am not really worried about that. So far, we only have prefixes like
`"fatal: "` or `"error: "`. The longest prefix is in `BUG_fl()` itself,
when we have access to the file name and the line number of the
triggering line, in which case it is `"BUG: <file>:<line>: "`. So as
long as nobody builds a custom version of Git that includes a file whose
path is insanely long, they should be fine. I am certain that Junio will
never accept such a file into git.git.

Oh, and even if anybody would introduce insanely long paths into their
fork of git.git, they would _still_ be safe because `BUG_fl()` limits
the prefix to 256 bytes, including `NUL`.

> You could also abort() after having written if we want to be more
> BUG()-like.

As I said, this is really a part of the patch I am not at all concerned
about. The prefixes are well under control, and I only addressed that
potential future breakage (that I believe falls squarely into YAGNI
territory) only because two reviewers seemed to be concerned.

I really believe that the care I put into the patch to safeguard against
overly long prefixes is seriously overkill.

Ciao,
Dscho

  reply	other threads:[~2019-10-29 20:09 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28 15:00 [PATCH 0/1] Fix t5516 flakiness in Visual Studio builds Johannes Schindelin via GitGitGadget
2019-10-28 15:00 ` [PATCH 1/1] vreportf(): avoid buffered write in favor of unbuffered one Johannes Schindelin via GitGitGadget
2019-10-29  3:18   ` Junio C Hamano
2019-10-29 12:30     ` Johannes Schindelin
2019-10-29 13:49       ` Jeff King
2019-10-29 14:13         ` Johannes Schindelin
2019-10-29 14:32           ` Jeff King
2019-10-29 20:09             ` Johannes Schindelin [this message]
2019-10-30  1:43               ` Junio C Hamano
2019-10-29 16:44         ` Junio C Hamano
2019-10-29 10:38   ` SZEDER Gábor
2019-10-29 12:38     ` Johannes Schindelin
2019-10-29 13:52       ` Jeff King
2019-10-29 14:18         ` Johannes Schindelin
2019-10-29 13:37 ` [PATCH v2 0/1] Fix t5516 flakiness in Visual Studio builds Johannes Schindelin via GitGitGadget
2019-10-29 13:37   ` [PATCH v2 1/1] vreportf(): avoid relying on stdio buffering Johannes Schindelin via GitGitGadget
2019-10-29 14:21     ` Alexandr Miloslavskiy
2019-10-29 19:57       ` Johannes Schindelin
2019-10-29 20:09         ` Jeff King
2019-10-29 20:24           ` Alexandr Miloslavskiy
2019-10-29 20:11         ` Alexandr Miloslavskiy
2019-10-29 20:01   ` [PATCH v3 0/1] Fix t5516 flakiness in Visual Studio builds Johannes Schindelin via GitGitGadget
2019-10-29 20:01     ` [PATCH v3 1/1] vreportf(): avoid relying on stdio buffering Johannes Schindelin via GitGitGadget
2019-10-29 20:32       ` Jeff King
2019-10-30  8:54         ` Johannes Schindelin
2019-10-31  6:24           ` Jeff King
2019-10-31 10:26             ` Johannes Schindelin
2019-10-31 15:48               ` Jeff King
2019-11-01 18:41                 ` Johannes Schindelin
2019-10-30  2:01       ` Junio C Hamano
2019-10-30  9:13         ` Johannes Schindelin
2019-10-30 10:44     ` [PATCH v4 0/1] Fix t5516 flakiness in Visual Studio builds Johannes Schindelin via GitGitGadget
2019-10-30 10:44       ` [PATCH v4 1/1] vreportf(): avoid relying on stdio buffering Johannes Schindelin via GitGitGadget
2019-11-02  4:05         ` Junio C Hamano

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