On Wed, Dec 13, 2017 at 9:40 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote:
> Christian Couder <christian.couder@xxxxxxxxx> writes:
>
>> Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
>> ---
>> 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.
Yeah, you are right I will fix this.
