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From: Junio C Hamano <gitster@pobox.com>
To: "SZEDER Gábor" <szeder.dev@gmail.com>
Cc: git@vger.kernel.org,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Jeff King <peff@peff.net>, Luke Diamand <luke@diamand.org>,
	Lars Schneider <larsxschneider@gmail.com>
Subject: Re: [PATCH 03/11] test-lib: introduce 'test_atexit'
Date: Mon, 18 Mar 2019 10:50:27 +0900	[thread overview]
Message-ID: <xmqqwokx6jdo.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20190314174024.GH28939@szeder.dev> ("SZEDER Gábor"'s message of "Thu, 14 Mar 2019 18:40:24 +0100")

SZEDER Gábor <szeder.dev@gmail.com> writes:

>> but it even skips when there is no point doing the
>> test_eval_ of the "accumulated" scriptlet when it is empty.
>
> But this is not, because $test_cleanup is initialized to this special
> value and it can never be empty, and indeed 'test_eval_' uses this
> condition:
>
>   if test -z "$immediate" || test $eval_ret = 0 ||
>      test -n "$expecting_failure" && test "$test_cleanup" != ":"
>
> and it never checks $test_cleanup's emptiness.

Yeah, I used "empty" not in the literal sense; I know why the "empty
in spirit" setting is a single colon for $test_cleanup.

I just did not realize that this new variable was using that exact
pattern and using ":" as the empty in spirit, and that was where my
fuzzy wordibng came from.

So in short, I misread the code, and part of that is because I was
misled by the comment:

> +	# This condition and resetting 'test_atexit_cleanup' below makes
> +	# sure that the registered cleanup commands are run only once.
> +	test : != "$test_atexit_cleanup" || return 0

It over-stresses the "run only once", but the true value of this is
that it avoids running an "empty in spirit" clean-up sequence.  

The avoidance of double execution merely takes advantage of this
implementation detail by "resetting" the variable is better
explained where the "resetting" happens (i.e. "we reset the variable
to the 'no-command' state, as we've run all of them here, but just
before the process finally exits, the helper will be called and we
do not want to run these commands again when it happens").

Thanks.

  reply	other threads:[~2019-03-18  1:50 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-13 12:24 [PATCH 00/11] tests: introduce 'test_atexit' SZEDER Gábor
2019-03-13 12:24 ` [PATCH 01/11] test-lib: fix interrupt handling with 'dash' and '--verbose-log -x' SZEDER Gábor
2019-03-14  2:18   ` Junio C Hamano
2019-03-14 14:50     ` SZEDER Gábor
2019-03-13 12:24 ` [PATCH 02/11] t/lib-git-daemon: make sure to kill the 'git-daemon' process SZEDER Gábor
2019-03-14  2:35   ` Junio C Hamano
2019-03-13 12:24 ` [PATCH 03/11] test-lib: introduce 'test_atexit' SZEDER Gábor
2019-03-14  3:21   ` Junio C Hamano
2019-03-14 17:40     ` SZEDER Gábor
2019-03-18  1:50       ` Junio C Hamano [this message]
2019-03-13 12:24 ` [PATCH 04/11] git-daemon: use 'test_atexit` to stop 'git-daemon' SZEDER Gábor
2019-03-13 12:24 ` [PATCH 05/11] tests: use 'test_atexit' to stop httpd SZEDER Gábor
2019-03-14  3:28   ` Junio C Hamano
2019-03-14  4:34     ` Junio C Hamano
2019-03-14 15:19     ` SZEDER Gábor
2019-03-13 12:24 ` [PATCH 06/11] t0301-credential-cache: use 'test_atexit' to stop the credentials helper SZEDER Gábor
2019-03-13 12:24 ` [PATCH 07/11] git p4 test: use 'test_atexit' to kill p4d and the watchdog process SZEDER Gábor
2019-03-13 12:24 ` [PATCH 08/11] git p4 test: clean up the p4d cleanup functions SZEDER Gábor
2019-03-13 12:24 ` [PATCH 09/11] git p4 test: simplify timeout handling SZEDER Gábor
2019-03-13 12:24 ` [PATCH 10/11] git p4 test: disable '-x' tracing in the p4d watchdog loop SZEDER Gábor
2019-03-13 12:24 ` [PATCH 11/11] t9811-git-p4-label-import: fix pipeline negation SZEDER Gábor

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