From: Jeff King <peff@peff.net>
Date: Mon, 07 Nov 2011 16:49:46 GMT
Subject: Re: [PATCH] blame.c: Properly initialize strbuf after calling textconv_object(), again
Message-ID: <20111107164946.GD27055@sigill.intra.peff.net>
In-Reply-To: <4EB7FEE6.9000609@gmail.com>

On Mon, Nov 07, 2011 at 04:53:10PM +0100, Sebastian Schuberth wrote:

> --- a/builtin/blame.c
> +++ b/builtin/blame.c
> @@ -2114,7 +2114,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
>  		case S_IFREG:
>  			if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
>  			    textconv_object(read_from, mode, null_sha1, &buf.buf, &buf_len)) {
> -				buf.alloc = buf_len;
> +				buf.alloc = buf_len + 1;
>  				buf.len = buf_len;
>  			}
>  			else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)

Your patch is correct in the sense that this fixes a bug, but it just
seems wrong to be touching the alloc parameter outside of the strbuf
code. It looks like the intent is to do the equivalent of:

  strbuf_add(&buf, some_heap_buf, len);
  free(some_heap_buf);

but avoid the extra allocation and copy. Should there be a
"strbuf_attach" function to encapsulate this pattern?

-Peff