From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: "René Scharfe" <l.s.r@web.de>
Cc: Git List <git@vger.kernel.org>,
Matheus Tavares <matheus.bernardino@usp.br>,
Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2] parallel-checkout: avoid dash local bug in tests
Date: Sat, 5 Jun 2021 21:09:10 +0200 [thread overview]
Message-ID: <20210605190910.GJ2947267@szeder.dev> (raw)
In-Reply-To: <472c1411-fcf8-862b-cef9-52c2c994914b@web.de>
On Sat, Jun 05, 2021 at 08:11:24PM +0200, René Scharfe wrote:
> The parallel checkout tests fail when run with /bin/dash on MacOS 11.4,
> reporting the following error:
>
> ./t2080-parallel-checkout-basics.sh: 33: local: 0: bad variable name
>
> That's because wc's output contains leading spaces and this version of
> dash erroneously expands the variable declaration as "local workers= 0",
> i.e. it tries to set the "workers" variable to the empty string and also
> declare a variable named "0", which not a valid name. This is a known
> dash bug (https://bugs.launchpad.net/ubuntu/+source/dash/+bug/139097).
Perhaps a more accurate wording for this bug would be:
... and even fairly recent versions of dash erroneously perform
field splitting on the expansion of the command substitution before
assigning it to a local variable.
I think the relevant part of POSIX is section 2.9.1 Simple Commands:
4. Each variable assignment shall be expanded for tilde expansion,
parameter expansion, command substitution, arithmetic expansion,
and quote removal prior to assigning the value.
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_01
Note that it didn't mention field splitting; though POSIX doesn't
specifies local variables in the first place, so...
Anyway, this bug has been fixed in v0.5.11 (2020-06-01).
This is an old bug, it was already present in v0.5.5 (2009-01-13); I
didn't check earlier versions.
> Work around it by passing the command output directly to test instead of
> storing it in a variable first. While at it, let grep count the number
> of lines instead of piping its output to wc, which is a bit shorter and
> more efficient.
A more debug-friendly alternative would be to save 'grep's output to a
temporary file and use 'test_line_count = $expected_workers'.
> Helped-by: Matheus Tavares Bernardino <matheus.bernardino@usp.br>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
> Changes since v1:
> - Explain the root cause.
> - Get rid of the local variable "workers".
> - Adjust title accordingly.
> - Still use grep -c, though.
> - Remove input redirection.
>
> t/lib-parallel-checkout.sh | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/t/lib-parallel-checkout.sh b/t/lib-parallel-checkout.sh
> index 21f5759732..66350d5207 100644
> --- a/t/lib-parallel-checkout.sh
> +++ b/t/lib-parallel-checkout.sh
> @@ -27,8 +27,7 @@ test_checkout_workers () {
> rm -f "$trace_file" &&
> GIT_TRACE2="$(pwd)/$trace_file" "$@" 2>&8 &&
>
> - local workers=$(grep "child_start\[..*\] git checkout--worker" "$trace_file" | wc -l) &&
> - test $workers -eq $expected_workers &&
> + test $(grep -c "child_start\[..*\] git checkout--worker" "$trace_file") -eq $expected_workers &&
> rm "$trace_file"
> } 8>&2 2>&4
>
> --
> 2.31.1
>
next prev parent reply other threads:[~2021-06-05 19:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-05 12:27 [PATCH] parallel-checkout: use grep -c to count workers in tests René Scharfe
2021-06-05 14:31 ` Matheus Tavares Bernardino
2021-06-05 15:20 ` René Scharfe
2021-06-05 15:30 ` René Scharfe
2021-06-05 18:11 ` [PATCH v2] parallel-checkout: avoid dash local bug " René Scharfe
2021-06-05 19:09 ` SZEDER Gábor [this message]
2021-06-06 1:01 ` René Scharfe
2021-06-05 19:56 ` Ævar Arnfjörð Bjarmason
2021-06-05 22:17 ` Matheus Tavares Bernardino
2021-06-05 22:21 ` Matheus Tavares Bernardino
2021-06-06 1:01 ` René Scharfe
2021-06-06 1:28 ` Junio C Hamano
2021-06-06 1:01 ` [PATCH v3] " René Scharfe
2021-06-06 1:41 ` Junio C Hamano
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210605190910.GJ2947267@szeder.dev \
--to=szeder.dev@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=l.s.r@web.de \
--cc=matheus.bernardino@usp.br \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).