just addressing the problem

misc/server/CHANGELOG.md

@@ -4,8 +4,6 @@
 
 - Use periodic and automatic bootstrap of Kademlia.
  See [PR 4838](https://github.com/libp2p/rust-libp2p/pull/4838).
-- Integrate Kademlia bootstrap function breaking change.
- See [PR 5349](https://github.com/libp2p/rust-libp2p/pull/5349).
 
 ## 0.12.6
 

misc/server/src/behaviour.rs

@@ -49,7 +49,7 @@ impl Behaviour {
  for peer in &BOOTNODES {
  kademlia.add_address(&PeerId::from_str(peer).unwrap(), bootaddr.clone());
  }
- kademlia.bootstrap();
+ kademlia.bootstrap().unwrap();
  Some(kademlia)
  } else {
  None

protocols/kad/CHANGELOG.md

@@ -19,7 +19,7 @@
  See [PR 5317](https://github.com/libp2p/rust-libp2p/pull/5317).
 - Use `web-time` instead of `instant`.
  See [PR 5347](https://github.com/libp2p/rust-libp2p/pull/5347).
-- Always trigger a query when bootstrapping.
+- Correctly handles the `NoKnownPeers` on automatic bootstrap.
  See [PR 5349](https://github.com/libp2p/rust-libp2p/pull/5349).
 
 ## 0.45.3

protocols/kad/src/behaviour.rs

@@ -914,10 +914,13 @@ where
  /// refreshed by initiating an additional bootstrapping query for each such
  /// bucket with random keys.
  ///
- /// Returns the `QueryId` for the entire bootstrapping process. The progress of bootstrapping is
+ /// Returns `Ok` if bootstrapping has been initiated with a self-lookup, providing the
+ /// `QueryId` for the entire bootstrapping process. The progress of bootstrapping is
  /// reported via [`Event::OutboundQueryProgressed{QueryResult::Bootstrap}`] events,
  /// with one such event per bootstrapping query.
  ///
+ /// Returns `Err` if bootstrapping is impossible due an empty routing table.
+ ///
  /// > **Note**: Bootstrapping requires at least one node of the DHT to be known.
  /// > See [`Behaviour::add_address`].
  ///
@@ -928,15 +931,21 @@ where
  /// > This parameter is used to call [`Behaviour::bootstrap`] periodically and automatically
  /// > to ensure a healthy routing table.
  pub fn bootstrap(&mut self) -> Result<QueryId, NoKnownPeers> {
+ self.bootstrap_status.on_started();
  let local_key = *self.kbuckets.local_key();
  let info = QueryInfo::Bootstrap {
  peer: *local_key.preimage(),
  remaining: None,
  step: ProgressStep::first(),
  };
  let peers = self.kbuckets.closest_keys(&local_key).collect::<Vec<_>>();
- let inner = QueryInner::new(info);
- self.queries.add_iter_closest(local_key, peers, inner)
+ if peers.is_empty() {
+ self.bootstrap_status.on_finish();
+ Err(NoKnownPeers())
+ } else {
+ let inner = QueryInner::new(info);
+ Ok(self.queries.add_iter_closest(local_key, peers, inner))
+ }
  }
 
  /// Establishes the local node as a provider of a value for the given key.
@@ -2519,7 +2528,9 @@ where
 
  // Poll bootstrap periodically and automatically.
  if let Poll::Ready(()) = self.bootstrap_status.poll_next_bootstrap(cx) {
- self.bootstrap();
+ if let Err(e) = self.bootstrap() {
+ tracing::warn!("Failed to trigger bootstrap: {e}");
+ }
  }
 
  loop {

protocols/kad/src/behaviour/test.rs

@@ -178,7 +178,7 @@ fn bootstrap() {
 
  let swarm_ids: Vec<_> = swarms.iter().map(Swarm::local_peer_id).cloned().collect();
 
- let qid = swarms[0].behaviour_mut().bootstrap();
+ let qid = swarms[0].behaviour_mut().bootstrap().unwrap();
 
  // Expected known peers
  let expected_known = swarm_ids.iter().skip(1).cloned().collect::<HashSet<_>>();