Merge branch 'nd/shallow-clone'

Fetching from a shallow-cloned repository used to be forbidden,
primarily because the codepaths involved were not carefully vetted
and we did not bother supporting such usage. This attempts to allow
object transfer out of a shallow-cloned repository in a controlled
way (i.e. the receiver become a shallow repository with truncated
history).

* nd/shallow-clone: (31 commits)
  t5537: fix incorrect expectation in test case 10
  shallow: remove unused code
  send-pack.c: mark a file-local function static
  git-clone.txt: remove shallow clone limitations
  prune: clean .git/shallow after pruning objects
  clone: use git protocol for cloning shallow repo locally
  send-pack: support pushing from a shallow clone via http
  receive-pack: support pushing to a shallow clone via http
  smart-http: support shallow fetch/clone
  remote-curl: pass ref SHA-1 to fetch-pack as well
  send-pack: support pushing to a shallow clone
  receive-pack: allow pushes that update .git/shallow
  connected.c: add new variant that runs with --shallow-file
  add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses
  receive/send-pack: support pushing from a shallow clone
  receive-pack: reorder some code in unpack()
  fetch: add --update-shallow to accept refs that update .git/shallow
  upload-pack: make sure deepening preserves shallow roots
  fetch: support fetching from a shallow repository
  clone: support remote shallow repository
  ...

1 files changed, 23 insertions, 4 deletions

diff --git a/send-pack.c b/send-pack.c
index ac14a4d090..6129b0fd8e 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -10,6 +10,7 @@
 #include "quote.h"
 #include "transport.h"
 #include "version.h"
+#include "sha1-array.h"
 
 static int feed_object(const unsigned char *sha1, int fd, int negative)
 {
@@ -28,7 +29,7 @@ static int feed_object(const unsigned char *sha1, int fd, int negative)
 /*
  * Make a pack stream and spit it out into file descriptor fd
  */
-static int pack_objects(int fd, struct ref *refs, struct extra_have_objects *extra, struct send_pack_args *args)
+static int pack_objects(int fd, struct ref *refs, struct sha1_array *extra, struct send_pack_args *args)
 {
 	/*
 	 * The child becomes pack-objects --revs; we feed
@@ -71,7 +72,7 @@ static int pack_objects(int fd, struct ref *refs, struct extra_have_objects *ext
 	 * parameters by writing to the pipe.
 	 */
 	for (i = 0; i < extra->nr; i++)
-		if (!feed_object(extra->array[i], po.in, 1))
+		if (!feed_object(extra->sha1[i], po.in, 1))
 			break;
 
 	while (refs) {
@@ -174,10 +175,25 @@ static int sideband_demux(int in, int out, void *data)
 	return ret;
 }
 
+static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
+{
+	struct strbuf *sb = cb;
+	if (graft->nr_parent == -1)
+		packet_buf_write(sb, "shallow %s\n", sha1_to_hex(graft->sha1));
+	return 0;
+}
+
+static void advertise_shallow_grafts_buf(struct strbuf *sb)
+{
+	if (!is_repository_shallow())
+		return;
+	for_each_commit_graft(advertise_shallow_grafts_cb, sb);
+}
+
 int send_pack(struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
 	      struct ref *remote_refs,
-	      struct extra_have_objects *extra_have)
+	      struct sha1_array *extra_have)
 {
 	int in = fd[0];
 	int out = fd[1];
@@ -215,6 +231,9 @@ int send_pack(struct send_pack_args *args,
 		return 0;
 	}
 
+	if (!args->dry_run)
+		advertise_shallow_grafts_buf(&req_buf);
+
 	/*
 	 * Finally, tell the other end!
 	 */
@@ -274,7 +293,7 @@ int send_pack(struct send_pack_args *args,
 	}
 
 	if (args->stateless_rpc) {
-		if (!args->dry_run && cmds_sent) {
+		if (!args->dry_run && (cmds_sent || is_repository_shallow())) {
 			packet_buf_flush(&req_buf);
 			send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
 		}