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From: Junio C Hamano <gitster@pobox.com>
To: Danh Doan <congdanhqx@gmail.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>, git@vger.kernel.org
Subject: Re: [PATCH v2 7/8] t4124: fix test for non-compliant diff(1)
Date: Mon, 23 Mar 2020 13:50:48 -0700
Message-ID: <xmqq8sjq4wyf.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200323150449.GC11801@danh.dev> (Danh Doan's message of "Mon, 23 Mar 2020 22:04:49 +0700")

Danh Doan <congdanhqx@gmail.com> writes:

> A comment in test-lib-functions::test_cmp mentions that
> there _is_ a diff out there that doesn't understand "-u".

That came from 82ebb0b6 (add test_cmp function for test scripts,
2008-03-12).

The change history at the end of the page:

  https://pubs.opengroup.org/onlinepubs/9699919799/utilities/diff.html

suggests that POSIX did not require "diff -u" until Issue 7, so it
is not surprising that the lack of "diff -u" to cause test_cmp to
fail was of real concern back in March 2008, as the application of
the errata have been only an year and half old, according to:

  https://www.opengroup.org/austin/docs/austin_325.txt

I vaguely recall that some open source projects only took the copied
context diffs and not unified ones the last time I checked, but
admittedly (1) that "last time" was a long time ago and (2) our
popularity and the fact that we do not understand copied context
[*1*] may have forced people to move away from "-c" and adopt "-u"
at the same time.  

So it might be OK to write off any system that does not understand
"diff -u" as an unusable trash these days ;-)

IOW, I think I am fine with assuming "diff -u" is available, like
Dscho's patch does.

Thanks.


[Footnote]

*1* It used to be my desire to teach "git apply" and "git diff" to
    also work with copied context format, but procrastination made
    it less and less relevant X-<.

  reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22  0:55 [PATCH v2 0/8] fix test failure with busybox Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 1/8] t4061: use POSIX compliant regex(7) Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 2/8] test-lib-functions: test_cmp: eval $GIT_TEST_CMP Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 3/8] t5003: drop the subshell in test_lazy_prereq Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 4/8] t5003: skip conversion test if unzip -a is unavailable Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 5/8] t5616: use rev-parse instead to get HEAD's object_id Đoàn Trần Công Danh
2020-03-22  0:55 ` [PATCH v2 6/8] t7063: drop non-POSIX argument "-ls" from find(1) Đoàn Trần Công Danh
2020-03-23 14:11   ` Johannes Schindelin
2020-03-23 14:37     ` Torsten Bögershausen
2020-03-23 15:11     ` Danh Doan
2020-03-23 20:30       ` Junio C Hamano
2020-03-23 15:55     ` Junio C Hamano
2020-03-24 22:31       ` Johannes Schindelin
2020-03-24 23:46         ` Junio C Hamano
2020-03-22  0:55 ` [PATCH v2 7/8] t4124: fix test for non-compliant diff(1) Đoàn Trần Công Danh
2020-03-23 13:58   ` Johannes Schindelin
2020-03-23 15:04     ` Danh Doan
2020-03-23 20:50       ` Junio C Hamano [this message]
2020-03-24  3:40         ` Danh Doan
2020-03-24 18:47           ` Junio C Hamano
2020-03-25 14:24             ` Danh Doan
2020-03-24 22:29           ` Johannes Schindelin
2020-03-24 23:37             ` Junio C Hamano
2020-03-25 18:23               ` Johannes Schindelin
2020-03-22  0:55 ` [PATCH v2 8/8] t5703: feed raw data into test-tool unpack-sideband Đoàn Trần Công Danh
2020-03-22  6:08 ` [PATCH v2 0/8] fix test failure with busybox Jeff King
2020-03-26  4:37 ` [PATCH v4 " Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 1/8] t4061: use POSIX compliant regex(7) Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 2/8] test-lib-functions: test_cmp: eval $GIT_TEST_CMP Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 3/8] t5003: drop the subshell in test_lazy_prereq Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 4/8] t5003: skip conversion test if unzip -a is unavailable Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 5/8] t5616: use rev-parse instead to get HEAD's object_id Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 6/8] t7063: drop non-POSIX argument "-ls" from find(1) Đoàn Trần Công Danh
2020-03-26  4:37   ` [PATCH v4 7/8] t4124: fix test for non-compliant diff(1) Đoàn Trần Công Danh
2020-03-27  1:18     ` Junio C Hamano
2020-03-26  4:37   ` [PATCH v4 8/8] t5703: feed raw data into test-tool unpack-sideband Đoàn Trần Công Danh

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