fix(kad): iterator progress to be decided by any of new peers

Cargo.toml

@@ -83,7 +83,7 @@ libp2p-floodsub = { version = "0.44.0", path = "protocols/floodsub" }
 libp2p-gossipsub = { version = "0.46.1", path = "protocols/gossipsub" }
 libp2p-identify = { version = "0.44.1", path = "protocols/identify" }
 libp2p-identity = { version = "0.2.8" }
-libp2p-kad = { version = "0.45.2", path = "protocols/kad" }
+libp2p-kad = { version = "0.45.3", path = "protocols/kad" }
 libp2p-mdns = { version = "0.45.1", path = "protocols/mdns" }
 libp2p-memory-connection-limits = { version = "0.2.0", path = "misc/memory-connection-limits" }
 libp2p-metrics = { version = "0.14.1", path = "misc/metrics" }

protocols/kad/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.45.3
+
+- The progress of the close query iterator shall be decided by ANY of the new peers.
+  See [PR 4932](https://github.com/libp2p/rust-libp2p/pull/4932).
+
 ## 0.45.2
 
 - Ensure `Multiaddr` handled and returned by `Behaviour` are `/p2p` terminated.

protocols/kad/Cargo.toml

@@ -3,7 +3,7 @@ name = "libp2p-kad"
 edition = "2021"
 rust-version = { workspace = true }
 description = "Kademlia protocol for libp2p"
-version = "0.45.2"
+version = "0.45.3"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"

protocols/kad/src/query/peers/closest.rs

@@ -175,10 +175,14 @@ impl ClosestPeersIter {
             },
         }
 
-        let num_closest = self.closest_peers.len();
-        let mut progress = false;
-
         // Incorporate the reported closer peers into the iterator.
+        //
+        // The iterator makes progress if:
+        //     1, the iterator did not yet accumulate enough closest peers.
+        //   OR
+        //     2, any of the new peers is closer to the target than any peer seen so far
+        //        (i.e. is the first entry after being incorporated)
+        let mut progress = self.closest_peers.len() < self.config.num_results.get();
         for peer in closer_peers {
             let key = peer.into();
             let distance = self.target.distance(&key);
@@ -187,11 +191,8 @@ impl ClosestPeersIter {
                 state: PeerState::NotContacted,
             };
             self.closest_peers.entry(distance).or_insert(peer);
-            // The iterator makes progress if the new peer is either closer to the target
-            // than any peer seen so far (i.e. is the first entry), or the iterator did
-            // not yet accumulate enough closest peers.
-            progress = self.closest_peers.keys().next() == Some(&distance)
-                || num_closest < self.config.num_results.get();
+
+            progress = self.closest_peers.keys().next() == Some(&distance) || progress;
         }
 
         // Update the iterator state.