Re: [PATCH v4 2/2] builtin/grep: add grep.fallbackToNoIndex config

> diff --git a/builtin/grep.c b/builtin/grep.c
> index 4229cae..6b7add6 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -755,9 +755,15 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>  			     PARSE_OPT_STOP_AT_NON_OPTION);
>  	grep_commit_pattern_type(pattern_type_arg, &opt);
>  
> -	if (use_index && !startup_info->have_repository)
> -		/* die the same way as if we did it at the beginning */
> -		setup_git_directory();
> +	if (use_index && !startup_info->have_repository) {
> +		int fallback = 0;
> +		git_config_get_bool("grep.fallbacktonoindex", &fallback);
> +		if (fallback)
> +			use_index = 0;
> +		else
> +			/* die the same way as if we did it at the beginning */
> +			setup_git_directory();
> +	}
>  
>  	/*
>  	 * skip a -- separator; we know it cannot be