From 121174a20618d88174784c5b2f1d905100f06223 Mon Sep 17 00:00:00 2001 From: tv Date: Thu, 22 Oct 2026 21:55:36 +0200 Subject: don't resend sync messages to up-to-date peers When an sync messages arrives and automerge has nothing to say about it, then no reply is generated. With c9279e4 it was assumed that every sync message gets an answer, so missing replies caused unnecessary resends. Now a reply is only awaited if the peer's last reported heads differ from ours. If the peer's heads become equal through a third peer without replying, the waiting will also abort if a ping or pong showss the same heads digest on both sides. --- src/swarm/sync.rs | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'src/swarm/sync.rs') diff --git a/src/swarm/sync.rs b/src/swarm/sync.rs index 0c7148e..e294201 100644 --- a/src/swarm/sync.rs +++ b/src/swarm/sync.rs @@ -110,9 +110,19 @@ async fn deliver_sync_to_peer(state: &AppState, peer: &str, retry_delivery: bool peer_state.needs_generate = false; let epoch = replica.epoch; let sent_before = peer_state.sync_state.sent_hashes.clone(); - let sync_doc = replica.doc.sync(); - let message = sync_doc.generate_sync_message(&mut peer_state.sync_state); - if message.is_some() { + let message = { + let sync_doc = replica.doc.sync(); + sync_doc.generate_sync_message(&mut peer_state.sync_state) + }; + // A peer whose heads are ours already has everything; Automerge + // answers only when it has something to say, so it will stay + // silent. Waiting for an answer would only end in a pointless + // resend. + let in_step = peer_state.sync_state.their_heads.as_ref() + == Some(&replica.doc.get_heads()); + if in_step { + peer_state.sync_in_step(); + } else if message.is_some() { let sent = peer_state .sync_state .sent_hashes -- cgit v1.3.1