Re: [PATCH] diff.c: guard config parser from value=NULL

> In fact we also guard for value="" as it doesn't make more sense
> for the variables here.
> 
> We do that by using a new function 'xstrdup_confval' to avoid code
> duplication.
> 
> By the way this changes a 'strdup' into 'xstrdup'.
> 
> Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
> ---
>  diff.c |   23 +++++++++++++----------
>  1 files changed, 13 insertions(+), 10 deletions(-)
> 
> diff --git a/diff.c b/diff.c
> index 5b8afdc..d51aecb 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -60,6 +60,14 @@ static struct ll_diff_driver {
>  	char *cmd;
>  } *user_diff, **user_diff_tail;
>  
> +static int xstrdup_confval(const char *dest, const char *var, const char *value)
> +{
> +	if (!value || !*value)
> +		return error("%s: lacks value", var);
> +	dest = xstrdup(value);
> +	return 0;
> +}
> +
>  /*
>   * Currently there is only "diff.<drivername>.command" variable;
>   * because there are "diff.color.<slot>" variables, we are parsing