Re: [PATCH] completion: do not cache if --git-completion-helper fails

> "git <cmd> --git-completion-helper" could fail if the command checks for
> a repo before parse_options(). If the result is cached, later on when
> the user moves to a worktree with repo, tab completion will still fail.
> 
> Avoid this by detecting errors and not cache the completion output. We
> can try again and hopefully succeed next time (e.g. when a repo is
> found).
> 
> Of course if --git-completion-helper fails permanently because of other
> reasons (*), this will slow down completion. But I don't see any better
> option to handle that case.

> (*) one of those cases is if __gitcomp_builtin is called on a command
>   that does not support --git-completion-helper. And we do have a
>   generic call
> 
>     __git_complete_common "$command"
> 
>   but this case is protected with __git_support_parseopt_helper so we're
>   good.
> 
> Reported-by: Felipe Contreras <felipe.contreras@gmail.com>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  contrib/completion/git-completion.bash | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 9f71bcde96..a515de8501 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -398,13 +398,15 @@ __gitcomp_builtin ()
>  	eval "options=\$$var"
>  
>  	if [ -z "$options" ]; then
> +		local nocache=
>  		# leading and trailing spaces are significant to make
>  		# option removal work correctly.
> -		options=" $incl $(__git ${cmd/_/ } --git-completion-helper) "
> +		options=" $incl $(__git ${cmd/_/ } --git-completion-helper) " || nocache=t

> +
>  		for i in $excl; do
>  			options="${options/ $i / }"
>  		done
> -		eval "$var=\"$options\""
> +		test -n "$nocache" || eval "$var=\"$options\""
>  	fi
>  
>  	__gitcomp "$options"
> -- 
> 2.22.0.rc0.322.g2b0371e29a
>