From: Denton Liu <liu.denton@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jakub Narebski <jnareb@gmail.com>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH 16/16] t4124: let sed open its own files
Date: Wed, 1 Jan 2020 03:24:43 -0500 [thread overview]
Message-ID: <20200101082443.GB5152@generichostname> (raw)
In-Reply-To: <xmqqfth1fl72.fsf@gitster-ct.c.googlers.com>
Hi Jakub and Junio,
On Mon, Dec 30, 2019 at 03:27:45PM -0800, Junio C Hamano wrote:
> Jakub Narebski <jnareb@gmail.com> writes:
>
> > Denton Liu <liu.denton@gmail.com> writes:
> >
> >> In one case, we were using a redirection operator to feed input into
> >> sed. However, since sed is capable of opening its own files, make sed
> >> open its own files instead of redirecting input into it.
> >
> > Could you please write in the commit message what advantages does this
> > change bring?
>
> A fair question.
>
> My version of short answer is "nothing---it is not wrong to write it
> either way, and it is not worth the patch churn to rewrite it from
> one form to the other, once the script is written".
In one of my earliest contributions to Git, Gábor suggested that since
since 'head' and 'sed' can open its own input file, there's no need to
redirect its standard input[1].
I assumed that letting these programs open their own input was one of
those minor "style cleanup" things that was done such as removing
spaces after redirection operators, indenting compound command blocks,
etc. Whenever I've been cleaning tests up, if I noticed a `sed <` in the
area, I'd apply the transformation as a style cleanup.
I guess the only tangible benefit I can think of is that programs which
have a file open can optimise on the fact that they can perform random
access on the file whereas with stdin, only linear access is allowed. I
don't know enough about the internals of various seds to be able to
comment on whether any of them actually take advantage of this, however.
Anyway, if no one else feels strongly about this, I can drop this patch
and I'll stop doing this cleanup in the future.
Thanks,
Denton
[1]: https://lore.kernel.org/git/20190317130539.GA23160@szeder.dev/
next prev parent reply other threads:[~2020-01-01 8:24 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-27 13:47 [PATCH 00/16] t: replace incorrect test_must_fail usage (part 2) Denton Liu
2019-12-27 13:47 ` [PATCH 01/16] t2018: remove trailing space from test description Denton Liu
2019-12-27 13:47 ` [PATCH 02/16] t2018: add space between function name and () Denton Liu
2019-12-27 21:03 ` Eric Sunshine
2019-12-27 13:47 ` [PATCH 03/16] t2018: use test_must_fail for failing git commands Denton Liu
2019-12-28 7:55 ` Eric Sunshine
2019-12-30 20:30 ` Jakub Narebski
2019-12-27 13:47 ` [PATCH 04/16] t2018: teach do_checkout() to accept `!` arg Denton Liu
2019-12-28 8:34 ` Eric Sunshine
2019-12-27 13:47 ` [PATCH 05/16] t2018: don't lose return code of git commands Denton Liu
2019-12-27 21:42 ` Eric Sunshine
2020-01-01 8:48 ` Denton Liu
2020-01-01 9:21 ` Eric Sunshine
2020-01-02 18:26 ` Junio C Hamano
2019-12-27 13:47 ` [PATCH 06/16] t2018: replace "sha" with "oid" Denton Liu
2019-12-27 13:47 ` [PATCH 07/16] t3030: use test_path_is_missing() Denton Liu
2019-12-27 13:47 ` [PATCH 08/16] t3310: extract common no_notes_merge_left() Denton Liu
2019-12-28 7:20 ` Eric Sunshine
2019-12-30 20:38 ` Jakub Narebski
2019-12-27 13:47 ` [PATCH 09/16] t3415: stop losing return codes of git commands Denton Liu
2019-12-27 13:47 ` [PATCH 10/16] t3415: increase granularity of test_auto_{fixup,squash}() Denton Liu
2019-12-27 13:47 ` [PATCH 11/16] t3419: stop losing return code of git command Denton Liu
2019-12-27 13:47 ` [PATCH 12/16] t3504: don't use `test_must_fail test_cmp` Denton Liu
2019-12-27 20:39 ` Johannes Sixt
2019-12-27 22:48 ` Junio C Hamano
2019-12-27 13:47 ` [PATCH 13/16] t3507: fix indentation Denton Liu
2019-12-27 13:47 ` [PATCH 14/16] t3507: use test_path_is_missing() Denton Liu
2019-12-27 13:47 ` [PATCH 15/16] t4124: only mark git command with test_must_fail Denton Liu
2019-12-27 13:47 ` [PATCH 16/16] t4124: let sed open its own files Denton Liu
2019-12-30 22:52 ` Jakub Narebski
2019-12-30 23:27 ` Junio C Hamano
2020-01-01 8:24 ` Denton Liu [this message]
2020-01-01 8:33 ` Eric Sunshine
2020-01-01 8:53 ` Denton Liu
2020-01-07 4:52 ` [PATCH v2 00/16] t: replace incorrect test_must_fail usage (part 2) Denton Liu
2020-01-07 4:52 ` [PATCH v2 01/16] t2018: remove trailing space from test description Denton Liu
2020-01-07 4:52 ` [PATCH v2 02/16] t2018: add space between function name and () Denton Liu
2020-01-07 4:53 ` [PATCH v2 03/16] t2018: improve style of if-statement Denton Liu
2020-01-07 4:53 ` [PATCH v2 04/16] t2018: use test_expect_code for failing git commands Denton Liu
2020-01-12 10:50 ` Eric Sunshine
2020-01-26 20:23 ` [PATCH v3] t2018: be more discerning when checking for expected exit codes Denton Liu
2020-01-07 4:53 ` [PATCH v2 05/16] t2018: teach do_checkout() to accept `!` arg Denton Liu
2020-01-07 4:53 ` [PATCH v2 06/16] t2018: don't lose return code of git commands Denton Liu
2020-01-07 4:53 ` [PATCH v2 07/16] t2018: replace "sha" with "oid" Denton Liu
2020-01-07 4:53 ` [PATCH v2 08/16] t3030: use test_path_is_missing() Denton Liu
2020-01-07 4:53 ` [PATCH v2 09/16] t3310: extract common notes_merge_files_gone() Denton Liu
2020-01-07 4:53 ` [PATCH v2 10/16] t3415: stop losing return codes of git commands Denton Liu
2020-01-07 4:53 ` [PATCH v2 11/16] t3415: increase granularity of test_auto_{fixup,squash}() Denton Liu
2020-01-07 4:53 ` [PATCH v2 12/16] t3419: stop losing return code of git command Denton Liu
2020-01-07 4:53 ` [PATCH v2 13/16] t3504: do check for conflict marker after failed cherry-pick Denton Liu
2020-01-07 4:53 ` [PATCH v2 14/16] t3507: fix indentation Denton Liu
2020-01-07 4:53 ` [PATCH v2 15/16] t3507: use test_path_is_missing() Denton Liu
2020-01-07 4:53 ` [PATCH v2 16/16] t4124: only mark git command with test_must_fail Denton Liu
2020-01-10 21:45 ` [PATCH v2 00/16] t: replace incorrect test_must_fail usage (part 2) Eric Sunshine
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