Two patches below fix two issues in got-read-pack.
The first patch is a bug fix, the second is a small performance fix.

Regarding the bug:

Using 'got send' to send the entire history of a branch to an empty
repository can result in some objects missing. A gotd server will
end up with a broken repository. I suspect git-daemon would catch
this problem, but I haven't tried to trigger this with git-daemon yet.

To reproduce this, run:
  got clone ssh://git@github.com/yellowman/nsh
to get this particular repo from Github which happens to trigger the bug.

Then set up a fresh repository on a gotd server and add it as a new remote
to the nsh repo cloned from github. Now use 'got send' to try to populate
this empty repository on the server. This will apparently succeed, but if
you now try to run e.g.  'got log' on the repository served by gotd, it
will erorr out because some commits will be missing.

Notably, in this situation the source repository has just one pack file
and no loose objects, so everything will be enumerated by got-read-pack.
In situations where not all objects can be enumerated from a single pack
file this bug won't trigger because we'll load the missing commits in
secondary pass.

ok?

-----------------------------------------------

 fix missing commits in pack files created with packed object enumeration
 
 got-read-pack forgot to send a tree-enumeration-done message to the
 main process if the tree of a given commit had already been traversed.
 The main process would then not add the corresponding commit to the
 pack file, even though it should be added.
 
 Found while using 'got send' towards gotd in order to populate an
 empty repository on the server with non-trivial history, where some
 commits always ended up missing due to this bug.
 
diff 87332a0e6e71182f1fb148d7f42e78105713285b 74aa0dc01f1f739557393098718e63131e75acd7
commit - 87332a0e6e71182f1fb148d7f42e78105713285b
commit + 74aa0dc01f1f739557393098718e63131e75acd7
blob - dd9fcfea23f63268577c4d5b91298a5a5106c61a
blob + 63ea6eca0b02d1b08d712fe7e8163f04098f3934
--- libexec/got-read-pack/got-read-pack.c
+++ libexec/got-read-pack/got-read-pack.c
@@ -1471,6 +1471,9 @@ enumeration_request(struct imsg *imsg, struct imsgbuf 
 		}
 
 		if (got_object_idset_contains(idset, tree_id)) {
+			err = send_tree_enumeration_done(ibuf);
+			if (err)
+				goto done;
 			got_object_qid_free(qid);
 			qid = NULL;
 			continue;

-----------------------------------------------

 avoid traversing enumrated commits more than once in got-read-pack
 
 Keep track of parent commits that will be processed as part
 of looping over the commit queue provided by the main process,
 and do not add these commits to the queue again.
 
 Fixes pointless traversal of commits on the queue which will
 simply be skipped. The end result is the same either way.
 
diff 74aa0dc01f1f739557393098718e63131e75acd7 00f162a8d0597c71a98d1429cb6ed38f13747d01
commit - 74aa0dc01f1f739557393098718e63131e75acd7
commit + 00f162a8d0597c71a98d1429cb6ed38f13747d01
blob - 63ea6eca0b02d1b08d712fe7e8163f04098f3934
blob + a64b44bf058deda0f69f2cd1ff50d1f307b0ffdf
--- libexec/got-read-pack/got-read-pack.c
+++ libexec/got-read-pack/got-read-pack.c
@@ -1019,7 +1019,8 @@ recv_object_id_queue(struct got_object_id_queue *queue
 }
 
 static const struct got_error *
-recv_object_id_queue(struct got_object_id_queue *queue, struct imsgbuf *ibuf)
+recv_object_id_queue(struct got_object_id_queue *queue,
+    struct got_object_idset *queued_ids, struct imsgbuf *ibuf)
 {
 	const struct got_error *err = NULL;
 	int done = 0;
@@ -1037,6 +1038,9 @@ recv_object_id_queue(struct got_object_id_queue *queue
 				return err;
 			memcpy(&qid->id, &ids[i], sizeof(qid->id));
 			STAILQ_INSERT_TAIL(queue, qid, entry);
+			err = got_object_idset_add(queued_ids, &qid->id, NULL);
+			if (err)
+				return err;
 		}
 	}
 
@@ -1362,7 +1366,7 @@ enumeration_request(struct imsg *imsg, struct imsgbuf 
 	struct got_commit_object *commit = NULL;
 	struct got_object_id *tree_id = NULL;
 	size_t totlen = 0;
-	struct got_object_idset *idset;
+	struct got_object_idset *idset, *queued_ids = NULL;
 	int i, idx, have_all_entries = 1;
 	struct enumerated_tree *trees = NULL;
 	size_t ntrees = 0, nalloc = 16;
@@ -1379,7 +1383,13 @@ enumeration_request(struct imsg *imsg, struct imsgbuf 
 		goto done;
 	}
 
-	err = recv_object_id_queue(&commit_ids, ibuf);
+	queued_ids = got_object_idset_alloc();
+	if (queued_ids == NULL) {
+		err = got_error_from_errno("got_object_idset_alloc");
+		goto done;
+	}
+
+	err = recv_object_id_queue(&commit_ids, queued_ids, ibuf);
 	if (err)
 		goto done;
 
@@ -1497,6 +1507,8 @@ enumeration_request(struct imsg *imsg, struct imsgbuf 
 			STAILQ_FOREACH(pid, parents, entry) {
 				if (got_object_idset_contains(idset, &pid->id))
 					continue;
+				if (got_object_idset_contains(queued_ids, &pid->id))
+					continue;
 				err = got_object_qid_alloc_partial(&qid);
 				if (err)
 					goto done;
@@ -1528,6 +1540,8 @@ done:
 	got_object_id_queue_free(&commit_ids);
 	if (idset)
 		got_object_idset_free(idset);
+	if (queued_ids)
+		got_object_idset_free(queued_ids);
 	for (i = 0; i < ntrees; i++) {
 		struct enumerated_tree *tree = &trees[i];
 		free(tree->buf);