[PATCH v3 00/28] First class shallow clone

Compared to v2 [1], v3 grows a bit. The biggest difference is .git/shallow is not updated by default (except when you clone from a shallow repository). When you send something, the "safe" refs that do not need new shallow roots are accepted at the receiver end, the others rejected.

To accept those other refs, either use "fetch --update-shallow" or enable receive.shallowupdate on the receiver side of a push.

Filtering "safe" refs requires walking through some commits, so it'll be more expensive than normal full clones. This is especially true for the receiver of a push (see 07/28 and 17/28). I envision shallow repos are used as upstream to archive old history, so this is not a good news. Commit cache (or pack v4) might help. We might even be able to move some work from receive-pack to send-pack to reduce server load..

[1] http://mid.gmane.org/1374314290-5976-1-git-send-email-pclouds@gmail.com

Nguyễn Thái Ngọc Duy (28):
  transport.h: remove send_pack prototype, already defined in send-pack.h
  send-pack: forbid pushing from a shallow repository
  clone: prevent --reference to a shallow repository
  update-server-info: do not publish shallow clones

   This part is just cleanup.

  Advertise shallow graft information on the server end
  connect.c: teach get_remote_heads to parse "shallow" lines
  shallow.c: add remove_reachable_shallow_points()
  shallow.c: add mark_new_shallow_refs()
  shallow.c: extend setup_*_shallow() to accept extra shallow points
  fetch-pack.c: move shallow update code out of fetch_pack()
  fetch-pack.h: one statement per bitfield declaration
  clone: support remote shallow repository
  fetch: support fetching from a shallow repository
  upload-pack: make sure deepening preserves shallow roots
  fetch: add --update-shallow to get refs that require updating .git/shallow

   Basic shallow fetch/clone support on git protocol

  receive-pack: reorder some code in unpack()
  Support pushing from a shallow clone
  New var GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses
  connected.c: add new variant that runs with --shallow-file
  receive-pack: allow pushing with new shallow roots
  send-pack: support pushing to a shallow clone
  remote-curl: pass ref SHA-1 to fetch-pack as well
  
   Push support

  Support fetch/clone over http
  receive-pack: support pushing to a shallow clone via http
  send-pack: support pushing from a shallow clone via http

   smart-http support

  git-clone.txt: remove shallow clone limitations
  clone: use git protocol for cloning shallow repo locally
  prune: clean .git/shallow after pruning objects

   miscellaneous

 Documentation/config.txt                  |   4 +
 Documentation/fetch-options.txt           |  14 +-
 Documentation/git-clone.txt               |   7 +-
 Documentation/gitremote-helpers.txt       |   7 +
 Documentation/technical/pack-protocol.txt |   7 +-
 builtin/clone.c                           |  18 +-
 builtin/fetch-pack.c                      |  23 +-
 builtin/fetch.c                           |  15 +-
 builtin/gc.c                              |   1 +
 builtin/prune.c                           |   4 +
 builtin/receive-pack.c                    | 248 +++++++++++++++++----
 builtin/send-pack.c                       |   5 +-
 cache.h                                   |   1 +
 commit.h                                  |  19 +-
 connect.c                                 |  14 +-
 connected.c                               |  42 +++-
 connected.h                               |   2 +
 environment.c                             |   6 +
 fetch-pack.c                              | 132 ++++++++++--
 fetch-pack.h                              |  29 +--
 git.c                                     |   2 +-
 remote-curl.c                             |  33 ++-
 remote.h                                  |   5 +-
 send-pack.c                               |  20 +-
 server-info.c                             |   9 +
 shallow.c                                 | 348 +++++++++++++++++++++++++++++-
 t/t5536-fetch-shallow.sh (new +x)         | 193 +++++++++++++++++
 t/t5537-push-shallow.sh (new +x)          | 184 ++++++++++++++++
 t/t5601-clone.sh                          |   7 +
 transport-helper.c                        |   6 +
 transport.c                               |  22 +-
 transport.h                               |  16 +-
 upload-pack.c                             |   8 +-
 33 files changed, 1323 insertions(+), 128 deletions(-)
 create mode 100755 t/t5536-fetch-shallow.sh
 create mode 100755 t/t5537-push-shallow.sh