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From: Denton Liu <liu.denton@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Git Mailing List" <git@vger.kernel.org>,
	"Eric Sunshine" <sunshine@sunshineco.com>,
	"Johannes Sixt" <j6t@kdbg.org>,
	"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH v4 01/14] t: teach test_cmp_rev to accept ! for not-equals
Date: Fri, 8 Nov 2019 00:23:10 -0800	[thread overview]
Message-ID: <20191108082310.GA2497@generichostname> (raw)
In-Reply-To: <xmqqpni3nj8j.fsf@gitster-ct.c.googlers.com>

On Fri, Nov 08, 2019 at 12:24:12PM +0900, Junio C Hamano wrote:
> Denton Liu <liu.denton@gmail.com> writes:
> 
> > Currently, in the case where we are using test_cmp_rev() to report
> > not-equals, we write `! test_cmp_rev`. However, since test_cmp_rev()
> > contains
> >
> > 	r1=$(git rev-parse --verify "$1") &&
> > 	r2=$(git rev-parse --verify "$2") &&
> >
> > In the case where `git rev-parse` segfaults and dies unexpectedly, the
> > failure will be ignored.

I'll probably reword this to

	In the case where we are using test_cmp_rev() to report
	not-equals, we write `! test_cmp_rev`. However, since
	test_cmp_rev() contains

		r1=$(git rev-parse --verify "$1") &&
		r2=$(git rev-parse --verify "$2") &&

	`! test_cmp_rev` will succeed if any of the rev-parses fail.
	This behavior is not desired. We want the rev-parses to _always_
	be successful.

because of your puzzlement below.

> 
> Good justification.  The last two lines are continuation of the
> sentence that begins the proposed log message, so downcase "In" at
> the beginning of the line.  Also, when we present the problem to be
> solved at the beginning, it is customary to describe the status quo,
> and "Currently, " is a noiseword that does not add much information,
> so drop it.

Thanks, I'll make a note to stop doing this in future patches as well.

[...]

> 
> >  test_cmp_rev () {
> > +	local inverted_op
> > +	inverted_op='!='
> > +	if test $# -ge 1 && test "x$1" = 'x!'
> > +	then
> > +	    inverted_op='='
> > +	    shift
> > +	fi
> 
> I'd rather avoid having to keep track of negation to reduce mental
> burden.  How about using = by default and != when '!' was given
> (which would be more natural to readers) and call it $op, and say
> "if ! test $r1 $op $r2" where it is used?

Good idea, I felt a little uneasy doing the inverted thing but it never
occurred to me to just negate the return code of `test`.

> 
> 
> >  	if test $# != 2
> >  	then
> >  		error "bug in the test script: test_cmp_rev requires two revisions, but got $#"
> >  	else
> >  		local r1 r2
> >  		r1=$(git rev-parse --verify "$1") &&
> >  		r2=$(git rev-parse --verify "$2") &&
> 
> If either of the calls fail, the assignment itself would fail, and
> the &&-cascade would stop without executing the if statment below.
> 
> I see the "!" feature, but where is the promised "fix" for
> segfaulting rev-parse?
> 
> Puzzled.

I suppose your puzzlement comes from my badly worded commit message
above. I meant to say that in the _hypothetical_ case that 
`git rev-parse` segfaults, it wouldn't be caught because we're
blanket-ignoring failures if we do `! test_cmp_rev`.

But I suppose I focused too much on segfaults. I guess I didn't realise
that the problem is more general than that; any failure of 
`git rev-parse` should be reported.

Thanks for the review,

Denton

  reply	other threads:[~2019-11-08  8:23 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-17 23:16 [PATCH 00/12] t5520: various test cleanup Denton Liu
2019-10-17 23:16 ` [PATCH 01/12] t5520: improve test style Denton Liu
2019-10-17 23:16 ` [PATCH 02/12] t5520: use sq for test case names Denton Liu
2019-10-17 23:17 ` [PATCH 03/12] t5520: let sed open its own input Denton Liu
2019-10-17 23:17 ` [PATCH 04/12] t5520: replace test -f with test_path_is_file Denton Liu
2019-10-17 23:26   ` Eric Sunshine
2019-10-17 23:35   ` [PATCH 4.5/12] t5520: replace test -f with test-lib functions Denton Liu
2019-10-18  0:11     ` Eric Sunshine
2019-10-17 23:17 ` [PATCH 05/12] t5520: remove spaces after redirect operator Denton Liu
2019-10-17 23:17 ` [PATCH 06/12] t5520: use test_line_count where possible Denton Liu
2019-10-17 23:17 ` [PATCH 07/12] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-10-17 23:31   ` Eric Sunshine
2019-10-17 23:17 ` [PATCH 08/12] t5520: use test_cmp_rev where possible Denton Liu
2019-10-17 23:41   ` Eric Sunshine
2019-10-18 18:52     ` Denton Liu
2019-10-23 13:53       ` Eric Sunshine
2019-10-17 23:17 ` [PATCH 09/12] t5520: test single-line files by git with test_cmp Denton Liu
2019-10-17 23:49   ` Eric Sunshine
2019-10-17 23:17 ` [PATCH 10/12] t5520: don't put git in upstream of pipe Denton Liu
2019-10-17 23:17 ` [PATCH 11/12] t5520: replace subshell cat comparison with test_cmp Denton Liu
2019-10-17 23:17 ` [PATCH 12/12] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-10-18 22:10 ` [PATCH v2 00/15] t5520: various test cleanup Denton Liu
2019-10-18 22:04   ` [PATCH v2 01/15] t7408: replace `test_must_fail test_path_is_file` Denton Liu
2019-10-19 11:58     ` Johannes Sixt
2019-10-18 22:04   ` [PATCH v2 09/15] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-10-18 22:04   ` [PATCH v2 11/15] t5520: test single-line files by git with test_cmp Denton Liu
2019-10-18 22:10   ` [PATCH v2 02/15] t: teach test_cmp_rev to accept ! for not-equals Denton Liu
2019-10-18 22:45     ` SZEDER Gábor
2019-10-18 22:10   ` [PATCH v2 03/15] t5520: improve test style Denton Liu
2019-10-18 22:10   ` [PATCH v2 04/15] t5520: use sq for test case names Denton Liu
2019-10-18 22:10   ` [PATCH v2 05/15] t5520: let sed open its own input Denton Liu
2019-10-18 22:10   ` [PATCH v2 06/15] t5520: replace test -f with test-lib functions Denton Liu
2019-10-18 22:10   ` [PATCH v2 07/15] t5520: remove spaces after redirect operator Denton Liu
2019-10-18 22:10   ` [PATCH v2 08/15] t5520: use test_line_count where possible Denton Liu
2019-10-18 22:10   ` [PATCH v2 10/15] t5520: use test_cmp_rev " Denton Liu
2019-10-18 22:10   ` [PATCH v2 12/15] t5520: don't put git in upstream of pipe Denton Liu
2019-10-18 22:10   ` [PATCH v2 13/15] t5520: replace subshell cat comparison with test_cmp Denton Liu
2019-10-18 22:10   ` [PATCH v2 14/15] t5520: remove redundant lines in test cases Denton Liu
2019-10-18 22:10   ` [PATCH v2 15/15] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-10-18 22:14   ` [PATCH v2 00/15] t5520: various test cleanup Denton Liu
2019-10-22 10:19   ` [PATCH v3 00/14] " Denton Liu
2019-10-22 10:19     ` [PATCH v3 01/14] t: teach test_cmp_rev to accept ! for not-equals Denton Liu
2019-10-22 10:19     ` [PATCH v3 02/14] t5520: improve test style Denton Liu
2019-10-22 10:19     ` [PATCH v3 03/14] t5520: use sq for test case names Denton Liu
2019-10-22 10:20     ` [PATCH v3 04/14] t5520: let sed open its own input Denton Liu
2019-10-22 10:20     ` [PATCH v3 05/14] t5520: replace test -f with test-lib functions Denton Liu
2019-10-22 10:20     ` [PATCH v3 06/14] t5520: remove spaces after redirect operator Denton Liu
2019-10-22 10:20     ` [PATCH v3 07/14] t5520: use test_line_count where possible Denton Liu
2019-10-22 10:20     ` [PATCH v3 08/14] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-10-22 10:20     ` [PATCH v3 09/14] t5520: use test_cmp_rev where possible Denton Liu
2019-10-22 10:20     ` [PATCH v3 10/14] t5520: test single-line files by git with test_cmp Denton Liu
2019-10-22 10:20     ` [PATCH v3 11/14] t5520: don't put git in upstream of pipe Denton Liu
2019-10-22 10:20     ` [PATCH v3 12/14] t5520: replace subshell cat comparison with test_cmp Denton Liu
2019-10-22 10:20     ` [PATCH v3 13/14] t5520: remove redundant lines in test cases Denton Liu
2019-10-22 10:20     ` [PATCH v3 14/14] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-10-24 23:21     ` [PATCH v3 00/14] t5520: various test cleanup Denton Liu
2019-10-25  3:44       ` Junio C Hamano
2019-11-04 19:17         ` Denton Liu
2019-11-06  2:37           ` Junio C Hamano
2019-11-07 18:51     ` [PATCH v4 " Denton Liu
2019-11-07 18:51       ` [PATCH v4 01/14] t: teach test_cmp_rev to accept ! for not-equals Denton Liu
2019-11-08  3:24         ` Junio C Hamano
2019-11-08  8:23           ` Denton Liu [this message]
2019-11-08 12:49             ` Junio C Hamano
2019-11-08 21:19               ` Denton Liu
2019-11-10  6:58                 ` Junio C Hamano
2019-11-07 18:51       ` [PATCH v4 02/14] t5520: improve test style Denton Liu
2019-11-07 18:51       ` [PATCH v4 03/14] t5520: use sq for test case names Denton Liu
2019-11-07 18:51       ` [PATCH v4 04/14] t5520: let sed open its own input Denton Liu
2019-11-07 18:51       ` [PATCH v4 05/14] t5520: replace test -f with test-lib functions Denton Liu
2019-11-07 18:51       ` [PATCH v4 06/14] t5520: remove spaces after redirect operator Denton Liu
2019-11-07 18:51       ` [PATCH v4 07/14] t5520: use test_line_count where possible Denton Liu
2019-11-07 18:51       ` [PATCH v4 08/14] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-11-07 18:51       ` [PATCH v4 09/14] t5520: use test_cmp_rev where possible Denton Liu
2019-11-07 18:51       ` [PATCH v4 10/14] t5520: test single-line files by git with test_cmp Denton Liu
2019-11-07 18:51       ` [PATCH v4 11/14] t5520: don't put git in upstream of pipe Denton Liu
2019-11-07 18:51       ` [PATCH v4 12/14] t5520: replace subshell cat comparison with test_cmp Denton Liu
2019-11-07 18:51       ` [PATCH v4 13/14] t5520: remove redundant lines in test cases Denton Liu
2019-11-07 18:51       ` [PATCH v4 14/14] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-11-12  0:13       ` [PATCH v5 00/14] t5520: various test cleanup Denton Liu
2019-11-12  0:13         ` [PATCH v5 01/14] t: teach test_cmp_rev to accept ! for not-equals Denton Liu
2019-11-12  6:52           ` Junio C Hamano
2019-11-12 19:38             ` [PATCH] fixup! " Denton Liu
2019-11-12  0:13         ` [PATCH v5 02/14] t5520: improve test style Denton Liu
2019-11-12  0:13         ` [PATCH v5 03/14] t5520: use sq for test case names Denton Liu
2019-11-12  0:13         ` [PATCH v5 04/14] t5520: let sed open its own input Denton Liu
2019-11-12  0:13         ` [PATCH v5 05/14] t5520: replace test -f with test-lib functions Denton Liu
2019-11-12  0:13         ` [PATCH v5 06/14] t5520: remove spaces after redirect operator Denton Liu
2019-11-12  0:13         ` [PATCH v5 07/14] t5520: use test_line_count where possible Denton Liu
2019-11-12  0:13         ` [PATCH v5 08/14] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-11-12  0:14         ` [PATCH v5 09/14] t5520: use test_cmp_rev where possible Denton Liu
2019-11-12  0:14         ` [PATCH v5 10/14] t5520: test single-line files by git with test_cmp Denton Liu
2019-11-12  5:17           ` Junio C Hamano
2019-11-12 23:06             ` Denton Liu
2019-11-12  0:14         ` [PATCH v5 11/14] t5520: don't put git in upstream of pipe Denton Liu
2019-11-12  0:14         ` [PATCH v5 12/14] t5520: replace subshell cat comparison with test_cmp Denton Liu
2019-11-12  0:14         ` [PATCH v5 13/14] t5520: remove redundant lines in test cases Denton Liu
2019-11-12  0:14         ` [PATCH v5 14/14] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-11-12 23:07         ` [PATCH v6 00/14] t5520: various test cleanup Denton Liu
2019-11-12 23:07           ` [PATCH v6 01/14] t: teach test_cmp_rev to accept ! for not-equals Denton Liu
2019-11-13  1:57             ` Junio C Hamano
2019-11-14  0:52               ` Denton Liu
2019-11-12 23:07           ` [PATCH v6 02/14] t5520: improve test style Denton Liu
2019-11-12 23:07           ` [PATCH v6 03/14] t5520: use sq for test case names Denton Liu
2019-11-12 23:07           ` [PATCH v6 04/14] t5520: let sed open its own input Denton Liu
2019-11-12 23:07           ` [PATCH v6 05/14] t5520: replace test -f with test-lib functions Denton Liu
2019-11-12 23:07           ` [PATCH v6 06/14] t5520: remove spaces after redirect operator Denton Liu
2019-11-12 23:08           ` [PATCH v6 07/14] t5520: use test_line_count where possible Denton Liu
2019-11-12 23:08           ` [PATCH v6 08/14] t5520: replace test -{n,z} with test-lib functions Denton Liu
2019-11-12 23:08           ` [PATCH v6 09/14] t5520: use test_cmp_rev where possible Denton Liu
2019-11-12 23:08           ` [PATCH v6 10/14] t5520: test single-line files by git with test_cmp Denton Liu
2019-11-12 23:08           ` [PATCH v6 11/14] t5520: don't put git in upstream of pipe Denton Liu
2019-11-12 23:08           ` [PATCH v6 12/14] t5520: replace $(cat ...) comparison with test_cmp Denton Liu
2019-11-12 23:08           ` [PATCH v6 13/14] t5520: remove redundant lines in test cases Denton Liu
2019-11-12 23:08           ` [PATCH v6 14/14] t5520: replace `! git` with `test_must_fail git` Denton Liu
2019-11-13  1:59           ` [PATCH v6 00/14] t5520: various test cleanup Junio C Hamano

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