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authorLibravatar Nguyễn Thái Ngọc Duy <pclouds@gmail.com>2013-12-05 20:02:32 +0700
committerLibravatar Junio C Hamano <gitster@pobox.com>2013-12-10 16:14:16 -0800
commitad491366de6c883cd04539cb86db31049201dfbd (patch)
treef94ce53d28f70ad6d971c12567d0cb6dbb5d5615 /Documentation
parentclone: prevent --reference to a shallow repository (diff)
downloadtgif-ad491366de6c883cd04539cb86db31049201dfbd.tar.xz
make the sender advertise shallow commits to the receiver
If either receive-pack or upload-pack is called on a shallow repository, shallow commits (*) will be sent after the ref advertisement (but before the packet flush), so that the receiver has the full "shape" of the sender's commit graph. This will be needed for the receiver to update its .git/shallow if necessary. This breaks the protocol for all clients trying to push to a shallow repo, or fetch from one. Which is basically the same end result as today's "is_repository_shallow() && die()" in receive-pack and upload-pack. New clients will be made aware of shallow upstream and can make use of this information. The sender must send all shallow commits that are sent in the following pack. It may send more shallow commits than necessary. upload-pack for example may choose to advertise no shallow commits if it knows in advance that the pack it's going to send contains no shallow commits. But upload-pack is the server, so we choose the cheaper way, send full .git/shallow and let the client deal with it. Smart HTTP is not affected by this patch. Shallow support on smart-http comes later separately. (*) A shallow commit is a commit that terminates the revision walker. It is usually put in .git/shallow in order to keep the revision walker from going out of bound because there is no guarantee that objects behind this commit is available. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/technical/pack-protocol.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index b898e97988..eb8edd1d4d 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -161,6 +161,7 @@ MUST peel the ref if it's an annotated tag.
----
advertised-refs = (no-refs / list-of-refs)
+ *shallow
flush-pkt
no-refs = PKT-LINE(zero-id SP "capabilities^{}"
@@ -174,6 +175,8 @@ MUST peel the ref if it's an annotated tag.
other-tip = obj-id SP refname LF
other-peeled = obj-id SP refname "^{}" LF
+ shallow = PKT-LINE("shallow" SP obj-id)
+
capability-list = capability *(SP capability)
capability = 1*(LC_ALPHA / DIGIT / "-" / "_")
LC_ALPHA = %x61-7A