Re: [PATCH v2 1/3] completion: bash: add __git_have_func helper

From: René Scharfe <l.s.r@web.de>
Date: Dec 30, 2020, 17:17 UTC
Message-ID: <1402dabd-089d-616a-ef79-ff1ae3fcb438@web.de>
In-Reply-To: <20201229170837.297857-2-felipe.contreras@gmail.com>

Am 29.12.20 um 18:08 schrieb Felipe Contreras:

Show 18 quoted lines

> This makes the code more readable, and also will help when new code
> wants to do similar checks.
>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---
>  contrib/completion/git-completion.bash | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 463a3124da..869c73ee2c 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -3358,15 +3358,19 @@ __git_support_parseopt_helper () {
>  	esac
>  }
>
> +__git_have_func () {
> +	declare -f $1 >/dev/null 2>/dev/null

I stumbled slightly over the lack of quoting. It doesn't matter for the callers below, but new callers passing arbitrary strings could cause strange effects:

	x() { echo x; }
	y() { echo y; }
	__git_have_func "x y" # succeeds

	__git_have_func -a # succeeds

I just skimmed patch 3, but it seems to call __git_have_func with user-supplied strings, so this might become relevant.

And then I wondered why use declare -f, which prints the function's body, when there is -F, which just prints the function's name. And why repeat /dev/null when redirecting stderr when the more shorter 2>&1 would do the same? None of hat was introduced by you patch, of course. Anyway, this seems to work for me:

	__git_have_func () {
		case "$1" in
		-*) return 1 ;;
		esac
		declare -F "$1" >/dev/null 2>&1
	}

Show 18 quoted lines

> +}
> +
>  __git_complete_command () {
>  	local command="$1"
>  	local completion_func="_git_${command//-/_}"
> -	if ! declare -f $completion_func >/dev/null 2>/dev/null &&
> -		declare -f _completion_loader >/dev/null 2>/dev/null
> +	if ! __git_have_func $completion_func &&
> +		__git_have_func _completion_loader
>  	then
>  		_completion_loader "git-$command"
>  	fi
> -	if declare -f $completion_func >/dev/null 2>/dev/null
> +	if __git_have_func $completion_func
>  	then
>  		$completion_func
>  		return 0
>