From: Jeff King <peff@peff.net>
To: Doan Tran Cong Danh <congdanhqx@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 1/3] t0028: eliminate non-standard usage of printf
Date: Thu, 31 Oct 2019 13:41:18 -0400 [thread overview]
Message-ID: <20191031174118.GA2133@sigill.intra.peff.net> (raw)
In-Reply-To: <20191031092618.29073-2-congdanhqx@gmail.com>
On Thu, Oct 31, 2019 at 04:26:16PM +0700, Doan Tran Cong Danh wrote:
> man 1p printf:
> In addition to the escape sequences shown in the Base Definitions
> volume of POSIX.1‐2008, Chapter 5, File Format Notation ('\\',
> '\a', '\b', '\f', '\n', '\r', '\t', '\v'), "\ddd", where ddd is a
> one, two, or three-digit octal number, shall be written as a byte
> with the numeric value specified by the octal number.
>
> printf '\xfe\xff' in an extension of some libc.
I don't think it's libc here at all, but rather the shell.
And as you note, dash does not handle this:
> With dash:
> $ printf '\xfe\xff' | xxd
> 00000000: 5c78 6665 5c78 6666 \xfe\xff
Which makes me wonder how these tests worked at all for people on say,
Debian systems.
I think the answer is that they don't trigger this prereq:
> write_utf16 () {
> if test_have_prereq NO_UTF16_BOM
> then
> - printf '\xfe\xff'
> + printf '\376\377'
> fi &&
> iconv -f UTF-8 -t UTF-16
> }
which comes from:
test_lazy_prereq NO_UTF16_BOM '
test $(printf abc | iconv -f UTF-8 -t UTF-16 | wc -c) = 6
'
Presumably on your system iconv is using musl's internal iconv, which
behaves differently than the glibc one.
So I think your patch is the right thing to do (hex escapes in shell
printf are definitely not portable), but we might want to note something
like:
This wasn't caught by most people running the tests, even though
common shells like dash don't handle hex escapes, because their
systems don't trigger the NO_UTF16_BOM prereq. But systems with musl
libc do; when combined with dash, the test fails.
-Peff
next prev parent reply other threads:[~2019-10-31 17:41 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 9:26 [PATCH 0/3] Linux with musl libc improvement Doan Tran Cong Danh
2019-10-31 9:26 ` [PATCH 1/3] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-10-31 17:41 ` Jeff King [this message]
2019-11-01 1:33 ` Danh Doan
2019-10-31 19:50 ` brian m. carlson
2019-10-31 9:26 ` [PATCH 2/3] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-10-31 18:11 ` Jeff King
2019-10-31 20:02 ` brian m. carlson
2019-11-01 1:40 ` Danh Doan
2019-10-31 9:26 ` [PATCH 3/3] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-10-31 10:38 ` Johannes Schindelin
2019-10-31 19:26 ` Jeff King
2019-11-01 4:49 ` Danh Doan
2019-11-01 8:25 ` [PATCH v2 0/3] Linux with musl libc improvement Doan Tran Cong Danh
2019-11-01 8:25 ` [PATCH v2 1/3] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-11-01 16:54 ` Jeff King
2019-11-01 8:25 ` [PATCH v2 2/3] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-11-01 16:56 ` Jeff King
2019-11-02 0:43 ` Danh Doan
2019-11-01 8:25 ` [PATCH v2 3/3] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-11-01 16:59 ` Jeff King
2019-11-02 1:02 ` Danh Doan
2019-11-02 12:20 ` Danh Doan
2019-11-05 8:00 ` Jeff King
2019-11-06 1:30 ` Junio C Hamano
2019-11-06 4:03 ` Jeff King
2019-11-06 10:03 ` Danh Doan
2019-11-07 5:56 ` Jeff King
2019-11-06 9:19 ` [PATCH v3 0/8] Correct internal working and output encoding Doan Tran Cong Danh
2019-11-06 9:19 ` [PATCH v3 1/8] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 2/8] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 3/8] t3900: demonstrate git-rebase problem with multi encoding Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 4/8] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 5/8] sequencer: reencode revert/cherry-pick's " Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 6/8] sequencer: reencode squashing commit's message Doan Tran Cong Danh
2019-11-06 9:20 ` [PATCH v3 7/8] sequencer: reencode old merge-commit message Doan Tran Cong Danh
2019-11-06 15:39 ` Eric Sunshine
2019-11-06 9:20 ` [PATCH v3 8/8] sequencer: reencode commit message for am/rebase --show-current-patch Doan Tran Cong Danh
2019-11-07 2:56 ` [PATCH v4 0/8] Correct internal working and output encoding Doan Tran Cong Danh
2019-11-07 2:56 ` [PATCH v4 1/8] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-11-07 2:56 ` [PATCH v4 2/8] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-11-07 6:18 ` Junio C Hamano
2019-11-07 2:56 ` [PATCH v4 3/8] t3900: demonstrate git-rebase problem with multi encoding Doan Tran Cong Danh
2019-11-07 6:02 ` Jeff King
2019-11-07 6:48 ` Danh Doan
2019-11-07 8:02 ` Jeff King
2019-11-07 10:51 ` Danh Doan
2019-11-11 8:22 ` Jeff King
2019-11-07 2:56 ` [PATCH v4 4/8] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-11-07 6:04 ` Jeff King
2019-11-07 2:56 ` [PATCH v4 5/8] sequencer: reencode revert/cherry-pick's " Doan Tran Cong Danh
2019-11-07 6:06 ` Jeff King
2019-11-07 2:56 ` [PATCH v4 6/8] sequencer: reencode squashing commit's message Doan Tran Cong Danh
2019-11-07 6:15 ` Jeff King
2019-11-07 2:56 ` [PATCH v4 7/8] sequencer: reencode old merge-commit message Doan Tran Cong Danh
2019-11-07 2:56 ` [PATCH v4 8/8] sequencer: reencode commit message for am/rebase --show-current-patch Doan Tran Cong Danh
2019-11-07 6:32 ` Jeff King
2019-11-07 7:48 ` Danh Doan
2019-11-07 8:03 ` Jeff King
2019-11-07 16:32 ` Danh Doan
2019-11-08 9:43 ` [PATCH v5 0/9] Improve odd encoding integration Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 1/9] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 2/9] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 3/9] t3900: demonstrate git-rebase problem with multi encoding Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 4/9] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 5/9] sequencer: reencode revert/cherry-pick's " Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 6/9] sequencer: reencode squashing commit's message Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 7/9] sequencer: reencode old merge-commit message Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 8/9] sequencer: reencode commit message for am/rebase --show-current-patch Doan Tran Cong Danh
2019-11-08 9:43 ` [PATCH v5 9/9] sequencer: fallback to sane label in making rebase todo list Doan Tran Cong Danh
2019-11-11 1:22 ` [PATCH v5 0/9] Improve odd encoding integration Junio C Hamano
2019-11-11 4:02 ` Junio C Hamano
2019-11-11 4:43 ` Danh Doan
2019-11-11 6:14 ` Junio C Hamano
2019-11-11 6:03 ` [PATCH v6 0/9] sequencer: handle other encoding better Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 1/9] t0028: eliminate non-standard usage of printf Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 2/9] configure.ac: define ICONV_OMITS_BOM if necessary Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 3/9] t3900: demonstrate git-rebase problem with multi encoding Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 4/9] sequencer: reencode to utf-8 before arrange rebase's todo list Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 5/9] sequencer: reencode revert/cherry-pick's " Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 6/9] sequencer: reencode squashing commit's message Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 7/9] sequencer: reencode old merge-commit message Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 8/9] sequencer: reencode commit message for am/rebase --show-current-patch Doan Tran Cong Danh
2019-11-11 6:03 ` [PATCH v6 9/9] sequencer: fallback to sane label in making rebase todo list Doan Tran Cong Danh
2019-11-11 8:39 ` Jeff King
2019-11-11 16:22 ` Phillip Wood
2019-11-11 18:26 ` Johannes Schindelin
2019-11-12 4:17 ` Junio C Hamano
2019-11-11 8:40 ` [PATCH v6 0/9] sequencer: handle other encoding better Jeff King
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