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From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: Stefan Beller <sbeller@google.com>,
	Junio C Hamano <gitster@pobox.com>,
	Jonathan Nieder <jrnieder@gmail.com>,
	Alex Riesen <raa.lkml@gmail.com>,
	"git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: [PATCH] for_each_string_list_item(): behave correctly for empty list
Date: Tue, 19 Sep 2017 15:45:23 +0200	[thread overview]
Message-ID: <CAM0VKjmuyp0pn29s8=diCpA0FPjjFJH-LcxQmOJH6Z-7WZNurA@mail.gmail.com> (raw)
In-Reply-To: <CAM0VKjn=KjTHBoubJKbxx7MasJ6wWcUFrCwrvr5oHwUCsfr_Pw@mail.gmail.com>

On Tue, Sep 19, 2017 at 3:38 PM, SZEDER Gábor <szeder.dev@gmail.com> wrote:
> A bit "futuristic" option along these lines could be something like
> this, using a scoped loop variable in the outer loop to ensure that
> it's executed at most once:
>
>   #define for_each_string_list_item(item,list) \
>       for (int f_e_s_l_i = 1; (list)->items && f_e_s_l_i; f_e_s_l_i = 0) \
>           for (item = (list)->items; item < (list)->items + (list)->nr; ++item)
>
> The high number of underscores are an attempt to make reasonably sure
> that the macro's loop variable doesn't shadow any variable in its
> callers or isn't being shadowed in the loop body, which might(?)
> trigger warnings in some compilers.

Well, and a poor attempt at that, because, of course, the loop
variable would still be shadowed in nested for_each_string_list_item
loops...  And our codebase has these loops nested in
entry.c:finish_delayed_checkout().

OTOH, we don't seem to care too much about shadowed variables, since
building with -Wshadow gives 91 warnings in current master...

      reply	other threads:[~2017-09-19 13:45 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-15 16:00 [PATCH] for_each_string_list_item(): behave correctly for empty list Michael Haggerty
2017-09-15 18:43 ` Jonathan Nieder
2017-09-16  4:06   ` Michael Haggerty
2017-09-16 11:51     ` SZEDER Gábor
2017-09-17 10:19       ` Michael Haggerty
2017-09-19 14:38     ` Kaartic Sivaraam
2017-09-20  1:38       ` Junio C Hamano
2017-09-20  1:43         ` Jonathan Nieder
2017-09-20  5:14           ` Junio C Hamano
2017-09-20  2:30       ` Jonathan Nieder
2017-09-20  3:54         ` Junio C Hamano
2017-09-20  5:27           ` [PATCH v2] for_each_string_list_item: avoid undefined behavior " Jonathan Nieder
2017-09-20  5:40             ` Junio C Hamano
2017-09-20  7:00             ` Michael Haggerty
2017-09-20  7:40             ` Kaartic Sivaraam
2017-09-20 12:22             ` [PATCH v2] doc: camelCase the config variables to improve readability Kaartic Sivaraam
2017-09-20 16:28             ` [PATCH v2] for_each_string_list_item: avoid undefined behavior for empty list Andreas Schwab
2017-09-20 17:31               ` Jonathan Nieder
2017-09-20 21:51                 ` Andreas Schwab
2017-09-21  1:12                   ` Junio C Hamano
2017-09-21 15:39                     ` Andreas Schwab
2017-09-20  7:35         ` [PATCH] for_each_string_list_item(): behave correctly " Kaartic Sivaraam
2017-09-17  0:59 ` Junio C Hamano
2017-09-17 10:24   ` Michael Haggerty
2017-09-18  0:37     ` Junio C Hamano
2017-09-19  0:08       ` Stefan Beller
2017-09-19  6:51         ` Michael Haggerty
2017-09-19 13:38           ` SZEDER Gábor
2017-09-19 13:45             ` SZEDER Gábor [this message]

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