From: Junio C Hamano <gitster@pobox.com>
To: Denton Liu <liu.denton@gmail.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: Sun, 10 Nov 2019 15:58:52 +0900 [thread overview]
Message-ID: <xmqq8sookyj7.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20191108211909.GA80210@generichostname> (Denton Liu's message of "Fri, 8 Nov 2019 13:19:09 -0800")
Denton Liu <liu.denton@gmail.com> writes:
> Hi Junio,
>
> On Fri, Nov 08, 2019 at 09:49:02PM +0900, Junio C Hamano wrote:
>> Denton Liu <liu.denton@gmail.com> writes:
>>
>> >> > local r1 r2
>> >> > r1=$(git rev-parse --verify "$1") &&
>> >> > r2=$(git rev-parse --verify "$2") &&
>> >>
>> >> If either of the calls fail, the assignment itself would fail, and
>> >> the &&-cascade would stop without executing the if statment below.
>> >>
>> r1=$(git rev-parse --verify "$1") ||
>> error "'$1' does not name a valid object"
>> r2=$(git rev-parse --verify "$2") ||
>> error "'$2' does not name a valid object"
>> if ! test "$r1" $op "$r2"
>> then
>> ... they do not compare the same ...
>> fi
>
> With your suggestion, we actually introduce subtle undesired behaviour.
> The `error` calls don't actually exit the function early. To make it
> work, we need to add && to the end of the `error` calls.
Not &&-at-the-end, but yes, we'd need some early return after
noticing a bad input from the caller.
You said earlier that one of the issues that motivated you to update
the helper was that this obvious typo
r1=... r2= ... &&
! test_rev_cmp "$r1" "$rr2"
would not be noticed. For such a fix, I do not think it is
sufficient to tweak the return value from the test_rev_cmp
helper function if we allow callers to expect failure like so.
And for that reason, your "allow 'test_rev_cmp ! R1 R2' syntax" part
of the change makes quite a lot of sense. That again allows the
callers to rely on failure return from test_rev_cmp as an error.
> I'm wondering why we want to do this, though. rev-parse should already
> output an error message on stderr in the case where the rev-parse fails.
>
> I guess the error message of "fatal: Needed a single revision" could
> probably be improved but that feels like an improvement that should be
> targeted to rev-parse.
Not really. The callers of rev-parse plumbing should expect that
exact string, if they want to differenciate different errors from
the program.
r1=$(git rev-parse --verify "$1") &&
r2=$(git rev-parse --verify "$2") || return 1
before we start the comparison between $r1 and $r2 may be a good way
to clarify the intent of the code. Using "&&" instead of "|| return"
and letting the whole function fail would not be incorrect, though.
Thanks.
next prev parent reply other threads:[~2019-11-10 6:59 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
2019-11-08 12:49 ` Junio C Hamano
2019-11-08 21:19 ` Denton Liu
2019-11-10 6:58 ` Junio C Hamano [this message]
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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