From: Stefan Beller <sbeller@google.com>
Date: Wed, 07 Feb 2018 19:00:37 GMT
Subject: Re: [PATCH v3 22/35] upload-pack: support shallow requests
Message-ID: <CAGZ79kauMhgP4Gjm=yVKSDGh0-WMSpNVCJRamfjnANyO5SWXTQ@mail.gmail.com>
In-Reply-To: <20180207011312.189834-23-bmwill@google.com>

On Tue, Feb 6, 2018 at 5:12 PM, Brandon Williams <bmwill@google.com> wrote:
> Add the 'shallow' feature to the protocol version 2 command 'fetch'
> which indicates that the server supports shallow clients and deepen
> requets.
>
> Signed-off-by: Brandon Williams <bmwill@google.com>
> ---
>  Documentation/technical/protocol-v2.txt |  67 +++++++++++++++-
>  serve.c                                 |   2 +-
>  t/t5701-git-serve.sh                    |   2 +-
>  upload-pack.c                           | 138 +++++++++++++++++++++++---------
>  upload-pack.h                           |   3 +
>  5 files changed, 173 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
> index 4d5096dae..fedeb6b77 100644
> --- a/Documentation/technical/protocol-v2.txt
> +++ b/Documentation/technical/protocol-v2.txt
> @@ -201,12 +201,42 @@ packet-lines:
>         to its base by position in pack rather than by an oid.  That is,
>         they can read OBJ_OFS_DELTA (ake type 6) in a packfile.
>
> +    shallow <oid>
> +       A client must notify the server of all objects for which it only

s/all objects/all commits/ for preciseness

> +       has shallow copies of (meaning that it doesn't have the parents
> +       of a commit) by supplying a 'shallow <oid>' line for each such
> +       object so that the serve is aware of the limitations of the
> +       client's history.
> +
> +    deepen <depth>
> +       Request that the fetch/clone should be shallow having a commit depth of
> +       <depth> relative to the remote side.

What does depth mean? number of commits, or number of edges?
Are there any special numbers (-1, 0, 1, max int) ?

From reading ahead: "Cannot be used with deepen-since, but
can be combined with deepen-relative" ?


> +
> +    deepen-relative
> +       Requests that the semantics of the "deepen" command be changed
> +       to indicate that the depth requested is relative to the clients
> +       current shallow boundary, instead of relative to the remote
> +       refs.
> +
> +    deepen-since <timestamp>
> +       Requests that the shallow clone/fetch should be cut at a
> +       specific time, instead of depth.  Internally it's equivalent of
> +       doing "rev-list --max-age=<timestamp>". Cannot be used with
> +       "deepen".
> +
> +    deepen-not <rev>
> +       Requests that the shallow clone/fetch should be cut at a
> +       specific revision specified by '<rev>', instead of a depth.
> +       Internally it's equivalent of doing "rev-list --not <rev>".
> +       Cannot be used with "deepen", but can be used with
> +       "deepen-since".

What happens if those are given in combination?