If either receive-pack or upload-pack is called on a shallow
repository, shallow graft points will be sent after the ref
advertisement (but before the packet flush), so that the client has
the full "shape" of the server's commit graph.

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.

Smart HTTP is not affected by this patch. Shallow support on
smart-http comes later separately.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com>
---
 Documentation/technical/pack-protocol.txt |  3 +++
 builtin/receive-pack.c                    |  4 +++-
 commit.h                                  |  1 +
 shallow.c                                 | 15 +++++++++++++++
 upload-pack.c                             |  6 ++++--
 5 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/Documentation/technical/pack-protocol.txt 
b/Documentation/technical/pack-protocol.txt
index b898e97..eb8edd1 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
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 67ce1ef..cc8c34f 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -178,6 +178,8 @@ static void write_head_info(void)
        if (!sent_capabilities)
                show_ref("capabilities^{}", null_sha1);
 
+       advertise_shallow_grafts(1);
+
        /* EOF */
        packet_flush(1);
 }
@@ -998,7 +1000,7 @@ int cmd_receive_pack(int argc, const char **argv, const 
char *prefix)
        if (!enter_repo(dir, 0))
                die("'%s' does not appear to be a git repository", dir);
 
-       if (is_repository_shallow())
+       if (is_repository_shallow() && stateless_rpc)
                die("attempt to push into a shallow repository");
 
        git_config(receive_pack_config, NULL);
diff --git a/commit.h b/commit.h
index bd841f4..a879526 100644
--- a/commit.h
+++ b/commit.h
@@ -205,6 +205,7 @@ extern int write_shallow_commits(struct strbuf *out, int 
use_pack_protocol);
 extern void setup_alternate_shallow(struct lock_file *shallow_lock,
                                    const char **alternate_shallow_file);
 extern char *setup_temporary_shallow(void);
+extern void advertise_shallow_grafts(int);
 
 int is_descendant_of(struct commit *, struct commit_list *);
 int in_merge_bases(struct commit *, struct commit *);
diff --git a/shallow.c b/shallow.c
index cdf37d6..9552512 100644
--- a/shallow.c
+++ b/shallow.c
@@ -220,3 +220,18 @@ void setup_alternate_shallow(struct lock_file 
*shallow_lock,
                *alternate_shallow_file = "";
        strbuf_release(&sb);
 }
+
+static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void 
*cb)
+{
+       int fd = *(int*)cb;
+       if (graft->nr_parent == -1)
+               packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
+       return 0;
+}
+
+void advertise_shallow_grafts(int fd)
+{
+       if (!is_repository_shallow())
+               return;
+       for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
+}
diff --git a/upload-pack.c b/upload-pack.c
index c989a73..38b2a29 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -758,6 +758,7 @@ static void upload_pack(void)
                reset_timeout();
                head_ref_namespaced(send_ref, &symref);
                for_each_namespaced_ref(send_ref, &symref);
+               advertise_shallow_grafts(1);
                packet_flush(1);
        } else {
                head_ref_namespaced(mark_our_ref, NULL);
@@ -835,8 +836,9 @@ int main(int argc, char **argv)
 
        if (!enter_repo(dir, strict))
                die("'%s' does not appear to be a git repository", dir);
-       if (is_repository_shallow())
-               die("attempt to fetch/clone from a shallow repository");
+       if (is_repository_shallow() && stateless_rpc)
+               die("attempt to push into a shallow repository");
+
        git_config(upload_pack_config, NULL);
        upload_pack();
        return 0;
-- 
1.8.2.83.gc99314b

--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to