Subject: Re: [PATCH 3/3] Revert "bash prompt: avoid command substitution when finalizing gitstring"

From: Junio C Hamano <[email-masked]>
Date: Wed, 21 Aug 2013 14:47:55 -0700

Brandon Casey <[email-masked]> writes:

> From: Brandon Casey <[email-masked]>
>
> This reverts commit 69a8141a5d81925b7e08cb228535e9ea4a7a02e3.
>
> Old Bash (3.0) which is distributed with RHEL 4.X and other ancient
> platforms that are still in wide use, does not have a printf that
> supports -v.  Let's revert this patch and go back to using printf
> in the traditional way.
>
> Signed-off-by: Brandon Casey <[email-masked]>
> ---

Is this something you can detect at load-time once, store the result
in a private variable and then switch on it at runtime, something
along the lines of...

	# on load...
	printf -v __git_printf_supports_v -- "%s" yes >/dev/null 2>&1
        
	...

	if test "${__git_printf_supports_v}" = yes
        then
		printf -v gitstring -- "$printf_format" "$gitstring"
	else
		gitstring=$(printf -- "$printf_format" "$gitstring")
        fi

>  contrib/completion/git-prompt.sh | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
> index a81ef5a..7698ec4 100644
> --- a/contrib/completion/git-prompt.sh
> +++ b/contrib/completion/git-prompt.sh
> @@ -433,11 +433,7 @@ __git_ps1 ()
>  	local gitstring="$c${b##refs/heads/}${f:+$z$f}$r$p"
>  
>  	if [ $pcmode = yes ]; then
> -		if [[ -n ${ZSH_VERSION-} ]]; then
> -			gitstring=$(printf -- "$printf_format" "$gitstring")
> -		else
> -			printf -v gitstring -- "$printf_format" "$gitstring"
> -		fi
> +		gitstring=$(printf -- "$printf_format" "$gitstring")
>  		PS1="$ps1pc_start$gitstring$ps1pc_end"
>  	else
>  		printf -- "$printf_format" "$gitstring"