From: Jeff King <peff@peff.net>
Date: Wed, 18 May 2011 08:09:47 GMT
Subject: Re: [PATCH 06/11] streaming: a new API to read from the object store
Message-ID: <20110518080947.GE27482@sigill.intra.peff.net>
In-Reply-To: <1305505831-31587-7-git-send-email-gitster@pobox.com>

On Sun, May 15, 2011 at 05:30:26PM -0700, Junio C Hamano wrote:

> +struct git_istream *open_istream(const unsigned char *sha1,
> +				 enum object_type *type,
> +				 unsigned long *sz)
> +{
> +	struct git_istream *st;
> +	struct object_info oi;
> +	const unsigned char *real = lookup_replace_object(sha1);
> +	enum input_source src = istream_source(real, type, &oi);
> +
> +	if (src < 0)
> +		return NULL;
> +
> +	st = xmalloc(sizeof(*st));
> +	st->source = src;
> +	if (open_istream_tbl[src](st, &oi, real, type, sz)) {
> +		if (open_istream_incore(st, &oi, real, type, sz)) {
> +			free(st);
> +			st = NULL;
> +		}
> +	}
> +	return st;
> +}

I assume the "sz" parameter is meant to be an output parameter with the
total size of the object. The open_istream_incore function fills it in
properly. But later, when you add open_istream_loose and
open_istream_pack_non_delta, neither of them actually touches the "sz"
parameter at all. So code like:

  struct git_istream *st;
  enum object_type type;
  unsigned long size;
  st = open_istream(sha1, &type, &size);

may or may not have "size" meaningful at this point, which seems like a
bug.

-Peff