upload-pack: ignore 'shallow' lines with unknown obj-ids

When the client sends a 'shallow' line for an object that the server does
not have, the server currently dies with the error: "did not find object
for shallow <obj-id>".  The client may have truncated the history at
the commit by fetching shallowly from a different server, or the commit
may have been garbage collected by the server. In either case, this
unknown commit is not relevant for calculating the pack that is to be
sent and can be safely ignored, and it is not used when recomputing where
the updated history of the client is cauterised.

The documentation in technical/pack-protocol.txt has been updated to
remove the restriction that "Clients MUST NOT mention an obj-id which it
does not know exists on the server". This requirement is not realistic
because clients cannot know whether an object has been garbage collected
by the server.

Signed-off-by: Michael Heemskerk <mheemskerk@atlassian.com>
Reviewed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index f1a51edf47f94f45ce916f7800924e6f135800e2..b898e97988311fe411c02f9f3fe45608e862a71a 100644 (file)
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -228,8 +228,7 @@ obtained through ref discovery.
 The client MUST write all obj-ids which it only has shallow copies
 of (meaning that it does not have the parents of a commit) as
 'shallow' lines so that the server is aware of the limitations of
-the client's history. Clients MUST NOT mention an obj-id which
-it does not know exists on the server.
+the client's history.
 
 The client now sends the maximum commit history depth it wants for
 this transaction, which is the number of commits it wants from the

diff --git a/upload-pack.c b/upload-pack.c
index bfa6279cc418278079bd95854adfe8d8301b6788..127e59a6037a14ad63648a727e873fe4a9e38381 100644 (file)
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -592,7 +592,7 @@ static void receive_needs(void)
                                die("invalid shallow line: %s", line);
                        object = parse_object(sha1);
                        if (!object)
-                               die("did not find object for %s", line);
+                               continue;
                        if (object->type != OBJ_COMMIT)
                                die("invalid shallow object %s", sha1_to_hex(sha1));
                        if (!(object->flags & CLIENT_SHALLOW)) {