From: Junio C Hamano <gitster@pobox.com>
Date: Sun, 11 Apr 2021 11:43:05 GMT
Subject: Re: [PATCH 09/12] mailinfo: also free strbuf lists when clearing mailinfo
Message-ID: <xmqq4kgdhws6.fsf@gitster.g>
In-Reply-To: <130ef89218a47adc7ee558e75672e0e4eb5f30ca.1617994052.git.gitgitgadget@gmail.com>

"Andrzej Hunt via GitGitGadget" <gitgitgadget@gmail.com> writes:

>  void clear_mailinfo(struct mailinfo *mi)
>  {
> -	int i;
> -
>  	strbuf_release(&mi->name);
>  	strbuf_release(&mi->email);
>  	strbuf_release(&mi->charset);
>  	strbuf_release(&mi->inbody_header_accum);
>  	free(mi->message_id);
>  
> -	if (mi->p_hdr_data)
> -		for (i = 0; mi->p_hdr_data[i]; i++)
> -			strbuf_release(mi->p_hdr_data[i]);
> -	free(mi->p_hdr_data);
> -	if (mi->s_hdr_data)
> -		for (i = 0; mi->s_hdr_data[i]; i++)
> -			strbuf_release(mi->s_hdr_data[i]);
> -	free(mi->s_hdr_data);

So, the original allows mi->p_hdr_data to be NULL and does not do
this freeing (the same for the .s_hdr_data member).

> +	strbuf_list_free(mi->p_hdr_data);
> +	strbuf_list_free(mi->s_hdr_data);

Is it safe to feed NULL to the helper?

        void strbuf_list_free(struct strbuf **sbs)
        {
                struct strbuf **s = sbs;

                while (*s) {
                        strbuf_release(*s);
                        free(*s++);
                }
                free(sbs);
        }