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Date: Thu, 20 Jun 2013 09:35:11 -0400
Message-ID: <CAJHLa0MrG3wkfQMRoeTp5nOwAcpLOVKd+c96NozTz=w3-0g4Jg@mail.gmail.com>
From: Jeff Garzik <jgarzik@bitpay.com>
To: Addy Yeow <ayeowch@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Cc: "bitcoin-development@lists.sourceforge.net"
	<bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Missing fRelayTxes in version message
Precedence: list

On Thu, Jun 20, 2013 at 3:13 AM, Addy Yeow <ayeowch@gmail.com> wrote:
> I personally don't treat the relay field as optional, i.e. it is there as
> 0x01 if it is set. Otherwise, it is simply a trailing zero byte. Hence, the
> right way of reading the packet as with any network packet is to first
> retrieve the header information, get the actual payload length, then parse
> the payload accordingly. I can also choose to include 0x00 for my relay
> field in my outgoing packet and reflect that accordingly in my length field
> in the header.

That works until another field is added in the same manner.

Implementations are expected to follow the standard logic of

if (more data)
   parse field X
if (more data)
   parse field X+1
if (more data)
   parse field X+2
etc.

Ugly or not, there is no point in changing now.  Updating the version
message to a radically different design, for simply cleanliness
reasons, is not sufficient cause to migrate the entire bitcoin
universe to a new and different version/feature negotiation setup.

--
Jeff Garzik
Senior Software Engineer and open source evangelist
BitPay, Inc.      https://bitpay.com/