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From: Junio C Hamano <gitster@pobox.com>
To: Brandon Williams <bmwill@google.com>
Cc: git@vger.kernel.org
Subject: Re: [WIP 08/15] connect: discover protocol version outside of get_remote_heads
Date: Thu, 07 Dec 2017 10:50:58 -0800	[thread overview]
Message-ID: <xmqq7etye5il.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20171204235823.63299-9-bmwill@google.com> (Brandon Williams's message of "Mon, 4 Dec 2017 15:58:16 -0800")

Brandon Williams <bmwill@google.com> writes:

> @@ -193,7 +195,17 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
>  		if (!conn)
>  			return args.diag_url ? 0 : 1;
>  	}
> -	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL, &shallow);
> +
> +	packet_reader_init(&reader, fd[0], NULL, 0);
> +
> +	switch (discover_version(&reader)) {
> +	case protocol_v1:
> +	case protocol_v0:
> +		get_remote_heads(&reader, &ref, 0, NULL, &shallow);
> +		break;
> +	case protocol_unknown_version:
> +		BUG("unknown protocol version");
> +	}

We see quite a few hunks just like this one appear in this patch.
The repetition is a bit disturbing.  I wonder if we want a wrapper
around the "reader-init && discover-version && return an error if
the protocol version is not known" dance.  That would allow us to
write this part of the code like so:

	struct packet_reader reader;

	if (connection_preamble(&reader, fd[0]))
		die("unknown protocol version");
	get_remote_heads(&reader, &ref, 0, NULL, &shallow);

or something like that.

By the way, is that really a BUG()?  Getting a connection and the
other end declaring a protocol version you do not yet understand is
not a bug in your program---it is a normal runtime error, no?

  reply	other threads:[~2017-12-07 18:51 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-20 17:18 [RFC] protocol version 2 Brandon Williams
2017-10-24  6:48 ` Junio C Hamano
2017-10-24 18:35   ` Brandon Williams
2017-10-25  1:22     ` Junio C Hamano
2017-10-26  0:59     ` Junio C Hamano
2017-10-25 13:09 ` Derrick Stolee
2017-10-25 18:10   ` Brandon Williams
2017-10-28 22:57 ` Philip Oakley
2017-10-31 18:42   ` Brandon Williams
2017-11-10 20:13 ` Jonathan Tan
2017-12-04 23:58 ` [WIP 00/15] " Brandon Williams
2017-12-04 23:58   ` [WIP 01/15] pkt-line: introduce packet_read_with_status Brandon Williams
2017-12-07 20:53     ` Stefan Beller
2017-12-08 18:03       ` Brandon Williams
2017-12-04 23:58   ` [WIP 02/15] pkt-line: introduce struct packet_reader Brandon Williams
2017-12-07 22:01     ` Stefan Beller
2017-12-08 18:11       ` Brandon Williams
2017-12-04 23:58   ` [WIP 03/15] pkt-line: add delim packet support Brandon Williams
2017-12-07 22:30     ` Stefan Beller
2017-12-08 20:08       ` Brandon Williams
2017-12-04 23:58   ` [WIP 04/15] upload-pack: convert to a builtin Brandon Williams
2017-12-06 21:59     ` Junio C Hamano
2017-12-07 16:14       ` Johannes Schindelin
2017-12-08 20:26         ` Junio C Hamano
2017-12-08 20:12       ` Brandon Williams
2017-12-04 23:58   ` [WIP 05/15] upload-pack: factor out processing lines Brandon Williams
2017-12-04 23:58   ` [WIP 06/15] transport: use get_refs_via_connect to get refs Brandon Williams
2017-12-06 22:10     ` Junio C Hamano
2017-12-07 18:40       ` Brandon Williams
2017-12-04 23:58   ` [WIP 07/15] connect: convert get_remote_heads to use struct packet_reader Brandon Williams
2017-12-06 22:39     ` Junio C Hamano
2017-12-08 20:19       ` Brandon Williams
2017-12-04 23:58   ` [WIP 08/15] connect: discover protocol version outside of get_remote_heads Brandon Williams
2017-12-07 18:50     ` Junio C Hamano [this message]
2017-12-07 19:04       ` Brandon Williams
2017-12-07 19:30         ` Junio C Hamano
2017-12-08 20:11           ` Brandon Williams
2017-12-04 23:58   ` [WIP 09/15] transport: store protocol version Brandon Williams
2017-12-04 23:58   ` [WIP 10/15] protocol: introduce enum protocol_version value protocol_v2 Brandon Williams
2017-12-04 23:58   ` [WIP 11/15] serve: introduce git-serve Brandon Williams
2017-12-07 23:42     ` Junio C Hamano
2017-12-08 20:25       ` Brandon Williams
2017-12-04 23:58   ` [WIP 12/15] ls-refs: introduce ls-refs server command Brandon Williams
2017-12-13 16:30     ` Philip Oakley
2017-12-04 23:58   ` [WIP 13/15] connect: request remote refs using v2 Brandon Williams
2017-12-04 23:58   ` [WIP 14/15] upload_pack: introduce fetch server command Brandon Williams
2017-12-04 23:58   ` [WIP 15/15] fetch-pack: perform a fetch using v2 Brandon Williams

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