From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: "Dale R. Worley" <worley@alum•mit.edu>,
Matthieu Moy <Matthieu.Moy@grenoble-inp•fr>,
git@vger•kernel.org
Subject: Re: [PATCH] pager: turn on "cat" optimization for DEFAULT_PAGER
Date: Tue, 03 Sep 2013 10:35:22 -0700 [thread overview]
Message-ID: <xmqqzjrtst9h.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20130903074150.GE3608@sigill.intra.peff.net> (Jeff King's message of "Tue, 3 Sep 2013 03:41:50 -0400")
Jeff King <peff@peff•net> writes:
> I'll venture my opinion. We should do this:
>
> -- >8 --
> Subject: pager: turn on "cat" optimization for DEFAULT_PAGER
>
> If the user specifies a pager of "cat" (or the empty
> string), whether it is in the environment or from config, we
> automagically optimize it out to mean "no pager" and avoid
> forking at all. We treat an empty pager variable similary.
>
> However, we did not apply this optimization when
> DEFAULT_PAGER was set to "cat" (or the empty string). There
> is no reason to treat DEFAULT_PAGER any differently. The
> optimization should not be user-visible (unless the user has
> a bizarre "cat" in their PATH). And even if it is, we are
> better off behaving consistently between the compile-time
> default and the environment and config settings.
>
> The stray "else" we are removing from this code was
> introduced by 402461a (pager: do not fork a pager if PAGER
> is set to empty., 2006-04-16). At that time, the line
> directly above used:
>
> if (!pager)
> pager = "less";
>
> as a fallback, meaning that it could not possibly trigger
> the optimization. Later, a3d023d (Provide a build time
> default-pager setting, 2009-10-30) turned that constant into
> a build-time setting which could be anything, but didn't
> loosen the "else" to let DEFAULT_PAGER use the optimization.
>
> Noticed-by: Dale R. Worley <worley@alum•mit.edu>
> Suggested-by: Matthieu Moy <Matthieu.Moy@grenoble-inp•fr>
> Signed-off-by: Jeff King <peff@peff•net>
> ---
Makes sense. Thanks.
> pager.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/pager.c b/pager.c
> index c1ecf65..fa19765 100644
> --- a/pager.c
> +++ b/pager.c
> @@ -54,7 +54,7 @@ const char *git_pager(int stdout_is_tty)
> pager = getenv("PAGER");
> if (!pager)
> pager = DEFAULT_PAGER;
> - else if (!*pager || !strcmp(pager, "cat"))
> + if (!*pager || !strcmp(pager, "cat"))
> pager = NULL;
>
> return pager;
next prev parent reply other threads:[~2013-09-03 17:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-26 19:57 the pager Dale R. Worley
2013-08-27 4:38 ` Junio C Hamano
2013-08-28 18:19 ` Dale R. Worley
2013-08-28 20:26 ` Junio C Hamano
2013-08-29 15:41 ` Dale R. Worley
2013-08-29 15:55 ` Matthieu Moy
2013-09-03 2:27 ` Dale R. Worley
2013-09-03 2:57 ` Jonathan Nieder
2013-09-03 7:41 ` [PATCH] pager: turn on "cat" optimization for DEFAULT_PAGER Jeff King
2013-09-03 17:35 ` Junio C Hamano [this message]
2013-11-20 17:24 ` Erik Faye-Lund
2013-11-20 17:30 ` Jeff King
2013-11-20 17:33 ` Erik Faye-Lund
2013-11-20 17:33 ` Junio C Hamano
2013-11-20 17:34 ` Erik Faye-Lund
2013-09-03 8:16 ` the pager Jeff King
2013-09-03 2:37 ` Dale R. Worley
2013-09-03 8:01 ` Jeff King
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