Re: [PATCH] ref-filter: initialize empty name or email fields

[Junio C Hamano <gitster@pobox.com>]

Mischa POSLAWSKY <git@shiar.nl> writes:

> Formatting $(taggername) on headerless tags such as v0.99 in Git
> causes a SIGABRT with error "munmap_chunk(): invalid pointer",
> because of an oversight in commit f0062d3b74 (ref-filter: free
> item->value and item->value->s, 2018-10-19).
>
> Signed-off-by: Mischa POSLAWSKY <git@shiar.nl>
> ---
> If I understand correctly, such tags cannot be produced normally anymore.
> Therefore I'm unsure how to make tests, and if that is even warranted.

Thanks for spotting.

I am not sure if the approach taken by this patch is the right one,
though.  I didn't follow the call/dataflow thoroughly, but if we
replace unfree-able "" with NULL in these places, wouldn't
fill_missing_values() take care of them?

>  ref-filter.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/ref-filter.c b/ref-filter.c
> index f27cfc8c3e..7338cfc671 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -1028,7 +1028,7 @@ static const char *copy_name(const char *buf)
>  		if (!strncmp(cp, " <", 2))
>  			return xmemdupz(buf, cp - buf);
>  	}
> -	return "";
> +	return xstrdup("");
>  }
>  
>  static const char *copy_email(const char *buf)
> @@ -1036,10 +1036,10 @@ static const char *copy_email(const char *buf)
>  	const char *email = strchr(buf, '<');
>  	const char *eoemail;
>  	if (!email)
> -		return "";
> +		return xstrdup("");
>  	eoemail = strchr(email, '>');
>  	if (!eoemail)
> -		return "";
> +		return xstrdup("");
>  	return xmemdupz(email, eoemail + 1 - email);
>  }