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From: Junio C Hamano <gitster@pobox.com>
To: Christian Couder <christian.couder@gmail.com>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"Thomas Rast" <tr@thomasrast.ch>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Christian Couder" <chriscool@tuxfamily.org>
Subject: Re: [PATCH 4/8] perf/run: use $default_value instead of $4
Date: Wed, 13 Dec 2017 12:40:30 -0800	[thread overview]
Message-ID: <xmqqbmj2wedd.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20171213151344.2138-5-chriscool@tuxfamily.org> (Christian Couder's message of "Wed, 13 Dec 2017 16:13:40 +0100")

Christian Couder <christian.couder@gmail.com> writes:

> Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
> ---
>  t/perf/run | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/t/perf/run b/t/perf/run
> index 43e4de49ef..bbd703dc4f 100755
> --- a/t/perf/run
> +++ b/t/perf/run
> @@ -105,7 +105,7 @@ get_var_from_env_or_config () {
>  	env_var="$1"
>  	conf_sec="$2"
>  	conf_var="$3"
> -	# $4 can be set to a default value
> +	default_value="$4" # optional
>  
>  	# Do nothing if the env variable is already set
>  	eval "test -z \"\${$env_var+x}\"" || return
> @@ -123,7 +123,7 @@ get_var_from_env_or_config () {
>  	conf_value=$(git config -f "$GIT_PERF_CONFIG_FILE" "$var") &&
>  	eval "$env_var=\"$conf_value\"" && return
>  
> -	test -n "${4+x}" && eval "$env_var=\"$4\""
> +	test -n "${default_value+x}" && eval "$env_var=\"$default_value\""

This conversion changes the behaviour.  Because default_value is
always set by your change in the previous hunk, we end up always
doing this eval.

The original says "If $4 is set, then ${4+x} becomes x and if $4 is
not set, ${4+x} is empty, so let's check if ${4+x} is a non-empty
string to see if $4 is set.  If ${4+x} is a non-empty string, that
means $4 was set so we do the eval.

If you want to be able to use this helper to specify a default value
of an empty string (which the orignal that used $4 did), then the
previous hunk must be corrected so that it does not unconditionally
set default_value to $4.  Perhaps like

	if test -n "${4+x}"
	then
		default_value=$4
	else
		unset default_value || :
	fi

or something.

>  }
>  
>  run_subsection () {

  reply	other threads:[~2017-12-13 20:40 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-13 15:13 [PATCH 0/8] Codespeed perf results Christian Couder
2017-12-13 15:13 ` [PATCH 1/8] perf/aggregate: fix checking ENV{GIT_PERF_SUBSECTION} Christian Couder
2017-12-13 15:13 ` [PATCH 2/8] perf/aggregate: refactor printing results Christian Couder
2017-12-13 15:13 ` [PATCH 3/8] perf/aggregate: implement codespeed JSON output Christian Couder
2017-12-13 18:25   ` Eric Sunshine
2017-12-14  8:47     ` Christian Couder
2017-12-13 20:33   ` Junio C Hamano
2017-12-14  8:57     ` Christian Couder
2017-12-14 17:31       ` Junio C Hamano
2017-12-13 15:13 ` [PATCH 4/8] perf/run: use $default_value instead of $4 Christian Couder
2017-12-13 20:40   ` Junio C Hamano [this message]
2017-12-13 20:54     ` Junio C Hamano
2017-12-14  9:00       ` Christian Couder
2017-12-14  8:59     ` Christian Couder
2017-12-13 15:13 ` [PATCH 5/8] perf/run: add conf_opts argument to get_var_from_env_or_config() Christian Couder
2017-12-13 15:13 ` [PATCH 6/8] perf/run: learn about perf.codespeedOutput Christian Couder
2017-12-13 15:13 ` [PATCH 7/8] perf/run: learn to send output to codespeed server Christian Couder
2017-12-13 15:13 ` [PATCH 8/8] perf/run: read GIT_TEST_REPO_NAME from perf.repoName Christian Couder
2017-12-13 16:02 ` [PATCH 0/8] Codespeed perf results Philip Oakley
2017-12-13 16:18   ` Christian Couder

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