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From: Junio C Hamano <gitster@pobox.com>
To: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, "René Scharfe" <l.s.r@web.de>,
	"Taylor Blau" <me@ttaylorr.com>,
	"Derrick Stolee" <stolee@gmail.com>,
	"Elijah Newren" <newren@gmail.com>,
	rsbecker@nexbridge.com,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Johannes Schindelin" <johannes.schindelin@gmx.de>
Subject: Re: [PATCH v6 2/7] archive --add-virtual-file: allow paths containing colons
Date: Wed, 25 May 2022 13:22:24 -0700	[thread overview]
Message-ID: <xmqq5ylt7473.fsf@gitster.g> (raw)
In-Reply-To: <7eebcf27b45eb13541d4abae70a374a0e35ab6b8.1653145696.git.gitgitgadget@gmail.com> (Johannes Schindelin via GitGitGadget's message of "Sat, 21 May 2022 15:08:11 +0000")

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

>  test_expect_success UNZIP 'git archive --format=zip --add-virtual-file' '
> +	if test_have_prereq FUNNYNAMES
> +	then
> +		PATHNAME=quoted:colon
> +	else
> +		PATHNAME=quoted
> +	fi &&
>  	git archive --format=zip >with_file_with_content.zip \
> +		--add-virtual-file=\"$PATHNAME\": \

The name is better, but this still limits what can be in PATHNAME.

Write either one of these:

		--add-virtual-file="\"$PATHNAME\":" \
		--add-virtual-file=\""$PATHNAME"\": \

to signal the intention better to future readers.  We are showing an
explicit dq-pair we want to pass to the c-unquote machinery, and we
are showing that we are not being unnecessarily loose by protecting
the string from getting word split.

Either is fine, but leaving it unquoted is not.

> +		test_path_is_file $PATHNAME &&

Ditto.  There is no reason to forbid future developers from futzing
the test to include space in the PATHNAME variable.  

IOW, I want us to be better than saying

    I know there is no $IFS whitespace now because I just wrote it.
    Because I do not think there is any need to test with a string
    with whitespace in it, I will leave the variable unquoted.
    Anybody who changes the variable and breaks this assumption have
    only themselves to blame for breaking the tests.  It is not my
    fault and it is not my problem.

which is the signal our readers would get from this patch (I would,
if I were reading this commit as a third-party), especially once
they become aware of the fact that this exact issue was already
pointed out during the review discussion.

Using double-quote appropriately sends a strong signal to reviewers
and future developers that we care about details.

A valid alternative is to write the assumption out where we
currently assign to PATHNAME.

	# The PATHNAME variable is used without quote in the code
	# below for such and such reasons, so you cannot use a $IFS
	# whitespace in it.
	if test_have_prereq FUNNYNAMES
	then
		...

If the "defensive" measure that is necessary to avoid a limitation
is too onerous, such an approach may be very much more preferrable
than preparing for future changes.  "for such and such reasons" is
a good place to justify why we avoid unnecessarily complex defensive
measure and restrict future changes in the documented way.

But in _this_ particular case, the "defensive" measure necessary is
merely just to quote the shell variables properly, which nobody
sensible would say too onerous.  I couldn't come up with anything
remotely plausible to fill "for such and such reasons" myself when I
tried to justify leaving the variables unquoted.

Regardless of the quoting issue, we probably want to comment on what
value exactly is in PATHNAME before the assignment, by the way.

E.g.

	# The PATHNAME variable holds a filename encoded like a
	# string constant in C language (e.g. "\060" is digit "0")
	if test_have_prereq FUNNYNAMES
	then
		PATHNAME=quoted:colon:\\060zero
	else
		PATHNAME=quoted\\060zero
	fi

That would not just protect only one aspect (i.e. we can pass a
colon into the resulting filename) this change but the path goes
through the c-unquoting rules.

Thanks.

  reply	other threads:[~2022-05-25 20:22 UTC|newest]

Thread overview: 140+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-26  8:41 [PATCH 0/5] scalar: implement the subcommand "diagnose" Johannes Schindelin via GitGitGadget
2022-01-26  8:41 ` [PATCH 1/5] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-01-26  9:34   ` René Scharfe
2022-01-26 22:20     ` Taylor Blau
2022-02-06 21:34       ` Johannes Schindelin
2022-01-27 19:38   ` Elijah Newren
2022-01-26  8:41 ` [PATCH 2/5] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-01-26  8:41 ` [PATCH 3/5] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-01-26 22:43   ` Taylor Blau
2022-01-27 15:14     ` Derrick Stolee
2022-02-06 21:38       ` Johannes Schindelin
2022-01-26  8:41 ` [PATCH 4/5] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-01-26 22:50   ` Taylor Blau
2022-01-27 15:17     ` Derrick Stolee
2022-01-27 18:59   ` Elijah Newren
2022-02-06 21:25     ` Johannes Schindelin
2022-01-26  8:41 ` [PATCH 5/5] scalar diagnose: show a spinner while staging content Johannes Schindelin via GitGitGadget
2022-01-27 15:19 ` [PATCH 0/5] scalar: implement the subcommand "diagnose" Derrick Stolee
2022-02-06 21:13   ` Johannes Schindelin
2022-02-06 22:39 ` [PATCH v2 0/6] " Johannes Schindelin via GitGitGadget
2022-02-06 22:39   ` [PATCH v2 1/6] archive: optionally add "virtual" files Johannes Schindelin via GitGitGadget
2022-02-07 19:55     ` René Scharfe
2022-02-07 23:30       ` Junio C Hamano
2022-02-08 13:12         ` Johannes Schindelin
2022-02-08 17:44           ` Junio C Hamano
2022-02-08 20:58             ` René Scharfe
2022-02-09 22:48               ` Junio C Hamano
2022-02-10 19:10                 ` René Scharfe
2022-02-10 19:23                   ` Junio C Hamano
2022-02-11 19:16                     ` René Scharfe
2022-02-11 21:27                       ` Junio C Hamano
2022-02-12  9:12                         ` René Scharfe
2022-02-13  6:25                           ` Junio C Hamano
2022-02-13  9:02                             ` René Scharfe
2022-02-14 17:22                               ` Junio C Hamano
2022-02-08 12:54       ` Johannes Schindelin
2022-02-06 22:39   ` [PATCH v2 2/6] scalar: validate the optional enlistment argument Johannes Schindelin via GitGitGadget
2022-02-06 22:39   ` [PATCH v2 3/6] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-02-07 19:55     ` René Scharfe
2022-02-08 12:08       ` Johannes Schindelin
2022-02-06 22:39   ` [PATCH v2 4/6] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-02-06 22:39   ` [PATCH v2 5/6] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-02-06 22:39   ` [PATCH v2 6/6] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-05-04 15:25   ` [PATCH v3 0/7] scalar: implement the subcommand "diagnose" Johannes Schindelin via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 1/7] archive: optionally add "virtual" files Johannes Schindelin via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 2/7] archive --add-file-with-contents: allow paths containing colons Johannes Schindelin via GitGitGadget
2022-05-07  2:06       ` Elijah Newren
2022-05-09 21:04         ` Johannes Schindelin
2022-05-04 15:25     ` [PATCH v3 3/7] scalar: validate the optional enlistment argument Johannes Schindelin via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 4/7] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 5/7] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 6/7] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-05-04 15:25     ` [PATCH v3 7/7] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-05-07  2:23     ` [PATCH v3 0/7] scalar: implement the subcommand "diagnose" Elijah Newren
2022-05-10 19:26     ` [PATCH v4 " Johannes Schindelin via GitGitGadget
2022-05-10 19:26       ` [PATCH v4 1/7] archive: optionally add "virtual" files Johannes Schindelin via GitGitGadget
2022-05-10 21:48         ` Junio C Hamano
2022-05-10 22:06           ` rsbecker
2022-05-10 23:21             ` Junio C Hamano
2022-05-11 16:14               ` René Scharfe
2022-05-11 19:27                 ` Junio C Hamano
2022-05-12 16:16                   ` René Scharfe
2022-05-12 18:15                     ` Junio C Hamano
2022-05-12 21:31                       ` Junio C Hamano
2022-05-14  7:06                         ` René Scharfe
2022-05-12 22:31           ` [PATCH] fixup! " Junio C Hamano
2022-05-10 19:26       ` [PATCH v4 2/7] archive --add-file-with-contents: allow paths containing colons Johannes Schindelin via GitGitGadget
2022-05-10 21:56         ` Junio C Hamano
2022-05-10 22:23           ` rsbecker
2022-05-19 18:12             ` Johannes Schindelin
2022-05-19 18:09           ` Johannes Schindelin
2022-05-19 18:44             ` Junio C Hamano
2022-05-10 19:27       ` [PATCH v4 3/7] scalar: validate the optional enlistment argument Johannes Schindelin via GitGitGadget
2022-05-17 14:51         ` Ævar Arnfjörð Bjarmason
2022-05-18 17:35           ` Junio C Hamano
2022-05-20  7:30             ` Ævar Arnfjörð Bjarmason
2022-05-20 15:55               ` Johannes Schindelin
2022-05-21  9:54                 ` Ævar Arnfjörð Bjarmason
2022-05-22  5:50                   ` Junio C Hamano
2022-05-24 12:25                     ` Johannes Schindelin
2022-05-24 18:11                       ` Ævar Arnfjörð Bjarmason
2022-05-24 19:29                         ` Junio C Hamano
2022-05-25 10:31                           ` Johannes Schindelin
2022-05-10 19:27       ` [PATCH v4 4/7] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-05-17 14:53         ` Ævar Arnfjörð Bjarmason
2022-05-10 19:27       ` [PATCH v4 5/7] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-05-10 19:27       ` [PATCH v4 6/7] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-05-10 19:27       ` [PATCH v4 7/7] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-05-17 15:03       ` [PATCH v4 0/7] scalar: implement the subcommand "diagnose" Ævar Arnfjörð Bjarmason
2022-05-17 15:28         ` rsbecker
2022-05-19 18:17           ` Johannes Schindelin
2022-05-19 18:17       ` [PATCH v5 " Johannes Schindelin via GitGitGadget
2022-05-19 18:17         ` [PATCH v5 1/7] archive: optionally add "virtual" files Johannes Schindelin via GitGitGadget
2022-05-20 14:41           ` René Scharfe
2022-05-20 16:21             ` Junio C Hamano
2022-05-19 18:17         ` [PATCH v5 2/7] archive --add-file-with-contents: allow paths containing colons Johannes Schindelin via GitGitGadget
2022-05-19 18:17         ` [PATCH v5 3/7] scalar: validate the optional enlistment argument Johannes Schindelin via GitGitGadget
2022-05-19 18:18         ` [PATCH v5 4/7] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-05-19 18:18         ` [PATCH v5 5/7] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-05-19 18:18         ` [PATCH v5 6/7] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-05-19 18:18         ` [PATCH v5 7/7] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-05-19 19:23         ` [PATCH v5 0/7] scalar: implement the subcommand "diagnose" Junio C Hamano
2022-05-21 15:08         ` [PATCH v6 " Johannes Schindelin via GitGitGadget
2022-05-21 15:08           ` [PATCH v6 1/7] archive: optionally add "virtual" files Johannes Schindelin via GitGitGadget
2022-05-25 21:11             ` Junio C Hamano
2022-05-26  9:09               ` René Scharfe
2022-05-26 17:10                 ` Junio C Hamano
2022-05-26 18:57                   ` René Scharfe
2022-05-26 20:16                     ` Junio C Hamano
2022-05-27 17:02                       ` René Scharfe
2022-05-27 19:01                         ` Junio C Hamano
2022-05-28  6:57                           ` René Scharfe
2022-05-21 15:08           ` [PATCH v6 2/7] archive --add-virtual-file: allow paths containing colons Johannes Schindelin via GitGitGadget
2022-05-25 20:22             ` Junio C Hamano [this message]
2022-05-25 21:42               ` Junio C Hamano
2022-05-25 22:34                 ` Junio C Hamano
2022-05-21 15:08           ` [PATCH v6 3/7] scalar: validate the optional enlistment argument Johannes Schindelin via GitGitGadget
2022-05-21 15:08           ` [PATCH v6 4/7] Implement `scalar diagnose` Johannes Schindelin via GitGitGadget
2022-05-21 15:08           ` [PATCH v6 5/7] scalar diagnose: include disk space information Johannes Schindelin via GitGitGadget
2022-05-21 15:08           ` [PATCH v6 6/7] scalar: teach `diagnose` to gather packfile info Matthew John Cheetham via GitGitGadget
2022-05-21 15:08           ` [PATCH v6 7/7] scalar: teach `diagnose` to gather loose objects information Matthew John Cheetham via GitGitGadget
2022-05-28 23:11           ` [PATCH v6+ 0/7] js/scalar-diagnose rebased Junio C Hamano
2022-05-28 23:11             ` [PATCH v6+ 1/7] archive: optionally add "virtual" files Junio C Hamano
2022-05-28 23:11             ` [PATCH v6+ 2/7] archive --add-virtual-file: allow paths containing colons Junio C Hamano
2022-06-15 18:16               ` Adam Dinwoodie
2022-06-15 20:00                 ` Junio C Hamano
2022-06-15 21:36                   ` Adam Dinwoodie
2022-06-18 20:19                     ` Johannes Schindelin
2022-06-18 22:05                       ` Junio C Hamano
2022-06-20  9:41                       ` Adam Dinwoodie
2022-05-28 23:11             ` [PATCH v6+ 3/7] scalar: validate the optional enlistment argument Junio C Hamano
2022-05-28 23:11             ` [PATCH v6+ 4/7] scalar: implement `scalar diagnose` Junio C Hamano
2022-06-10  2:08               ` Ævar Arnfjörð Bjarmason
2022-06-10 16:44                 ` Junio C Hamano
2022-06-10 17:35                   ` Ævar Arnfjörð Bjarmason
2022-05-28 23:11             ` [PATCH v6+ 5/7] scalar diagnose: include disk space information Junio C Hamano
2022-05-28 23:11             ` [PATCH v6+ 6/7] scalar: teach `diagnose` to gather packfile info Junio C Hamano
2022-05-28 23:11             ` [PATCH v6+ 7/7] scalar: teach `diagnose` to gather loose objects information Junio C Hamano
2022-05-30 10:12             ` [PATCH v6+ 0/7] js/scalar-diagnose rebased Johannes Schindelin
2022-05-30 17:37               ` Junio C Hamano

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