Merge branch 'jt/fetch-pack-in-vain-count-with-stateless'

When "git fetch" tries to find where the history of the repository
it runs in has diverged from what the other side has, it has a
mechanism to avoid digging too deep into irrelevant side branches.
This however did not work well over the "smart-http" transport due
to a design bug, which has been fixed.

* jt/fetch-pack-in-vain-count-with-stateless:
  fetch-pack: do not reset in_vain on non-novel acks

Author: gitster

fetch-pack.c

@@ -428,10 +428,17 @@ static int find_common(struct fetch_pack_args *args,
 						const char *hex = sha1_to_hex(result_sha1);
 						packet_buf_write(&req_buf, "have %s\n", hex);
 						state_len = req_buf.len;
-					}
+						/*
+						 * Reset in_vain because an ack
+						 * for this commit has not been
+						 * seen.
+						 */
+						in_vain = 0;
+					} else if (!args->stateless_rpc
+						   || ack != ACK_common)
+						in_vain = 0;
 					mark_common(commit, 0, 1);
 					retval = 0;
-					in_vain = 0;
 					got_continue = 1;
 					if (ack == ACK_ready) {
 						clear_prio_queue(&rev_list);