Revert two "no-done" reverts

Last night I had to make these two emergency reverts, but now we have a
better understanding of which part of the topic was broken, let's get rid
of the revert to fix it correctly.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch-pack.c

@@ -15,6 +15,7 @@ static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
 static int unpack_limit = 100;
 static int prefer_ofs_delta = 1;
+static int no_done = 0;
 static struct fetch_pack_args args = {
 	/* .uploadpack = */ "git-upload-pack",
 };
@@ -250,6 +251,7 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 	const unsigned char *sha1;
 	unsigned in_vain = 0;
 	int got_continue = 0;
+	int got_ready = 0;
 	struct strbuf req_buf = STRBUF_INIT;
 	size_t state_len = 0;
 
@@ -288,6 +290,7 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 			struct strbuf c = STRBUF_INIT;
 			if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 			if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
+			if (no_done)            strbuf_addstr(&c, " no-done");
 			if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 			if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 			if (args.use_thin_pack) strbuf_addstr(&c, " thin-pack");
@@ -406,8 +409,10 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 					retval = 0;
 					in_vain = 0;
 					got_continue = 1;
-					if (ack == ACK_ready)
+					if (ack == ACK_ready) {
 						rev_list = NULL;
+						got_ready = 1;
+					}
 					break;
 					}
 				}
@@ -421,8 +426,10 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 		}
 	}
 done:
+	if (!got_ready || !no_done) {
 		packet_buf_write(&req_buf, "done\n");
 		send_request(fd[1], &req_buf);
+	}
 	if (args.verbose)
 		fprintf(stderr, "done\n");
 	if (retval != 0) {
@@ -725,6 +732,11 @@ static struct ref *do_fetch_pack(int fd[2],
 		if (args.verbose)
 			fprintf(stderr, "Server supports multi_ack_detailed\n");
 		multi_ack = 2;
+		if (server_supports("no-done")) {
+			if (args.verbose)
+				fprintf(stderr, "Server supports no-done\n");
+			no_done = 1;
+		}
 	}
 	else if (server_supports("multi_ack")) {
 		if (args.verbose)

upload-pack.c

@@ -27,6 +27,7 @@ static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<
 static unsigned long oldest_have;
 
 static int multi_ack, nr_our_refs;
+static int no_done;
 static int use_thin_pack, use_ofs_delta, use_include_tag;
 static int no_progress, daemon_mode;
 static int shallow_nr;
@@ -431,6 +432,7 @@ static int get_common_commits(void)
 	char last_hex[41];
 	int got_common = 0;
 	int got_other = 0;
+	int sent_ready = 0;
 
 	save_commit_buffer = 0;
 
@@ -440,10 +442,17 @@ static int get_common_commits(void)
 
 		if (!len) {
 			if (multi_ack == 2 && got_common
-			    && !got_other && ok_to_give_up())
+			    && !got_other && ok_to_give_up()) {
+				sent_ready = 1;
 				packet_write(1, "ACK %s ready\n", last_hex);
+			}
 			if (have_obj.nr == 0 || multi_ack)
 				packet_write(1, "NAK\n");
+
+			if (no_done && sent_ready) {
+				packet_write(1, "ACK %s\n", last_hex);
+				return 0;
+			}
 			if (stateless_rpc)
 				exit(0);
 			got_common = 0;
@@ -457,9 +466,10 @@ static int get_common_commits(void)
 				got_other = 1;
 				if (multi_ack && ok_to_give_up()) {
 					const char *hex = sha1_to_hex(sha1);
-					if (multi_ack == 2)
+					if (multi_ack == 2) {
+						sent_ready = 1;
 						packet_write(1, "ACK %s ready\n", hex);
-					else
+					} else
 						packet_write(1, "ACK %s continue\n", hex);
 				}
 				break;
@@ -535,6 +545,8 @@ static void receive_needs(void)
 			multi_ack = 2;
 		else if (strstr(line+45, "multi_ack"))
 			multi_ack = 1;
+		if (strstr(line+45, "no-done"))
+			no_done = 1;
 		if (strstr(line+45, "thin-pack"))
 			use_thin_pack = 1;
 		if (strstr(line+45, "ofs-delta"))
@@ -628,7 +640,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow no-progress"
-		" include-tag multi_ack_detailed";
+		" include-tag multi_ack_detailed no-done";
 	struct object *o = parse_object(sha1);
 
 	if (!o)