change ActiveLeaves to contain at most one activated (#3525)

* change ActiveLeaves to contain at most one activated

* fix test

polkadot/Cargo.lock

@@ -5932,7 +5932,6 @@ dependencies = [
  "polkadot-primitives",
  "rand 0.8.4",
  "sc-network",
- "smallvec 1.6.1",
  "sp-application-crypto",
  "sp-core",
  "sp-keyring",
@@ -5962,7 +5961,6 @@ dependencies = [
  "polkadot-primitives",
  "rand 0.8.4",
  "sc-network",
- "smallvec 1.6.1",
  "sp-application-crypto",
  "sp-core",
  "sp-keyring",

polkadot/node/core/av-store/src/tests.rs

@@ -255,15 +255,12 @@ fn runtime_api_error_does_not_stop_the_subsystem() {
 
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: vec![ActivatedLeaf {
-					hash: new_leaf,
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}].into(),
-				deactivated: vec![].into(),
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: new_leaf,
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let header = Header {
@@ -806,15 +803,12 @@ fn we_dont_miss_anything_if_import_notifications_are_missed() {
 
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: vec![ActivatedLeaf {
-					hash: new_leaf,
-					number: 4,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}].into(),
-				deactivated: vec![].into(),
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: new_leaf,
+				number: 4,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		assert_matches!(
@@ -1139,15 +1133,12 @@ async fn import_leaf(
 
 	overseer_signal(
 		virtual_overseer,
-		OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
-				hash: new_leaf,
-				number: 1,
-				status: LeafStatus::Fresh,
-				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: vec![].into(),
-		}),
+		OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+			hash: new_leaf,
+			number: 1,
+			status: LeafStatus::Fresh,
+			span: Arc::new(jaeger::Span::Disabled),
+		})),
 	).await;
 
 	assert_matches!(

polkadot/node/network/availability-distribution/Cargo.toml

@@ -31,4 +31,3 @@ sc-network = { git = "https://github.com/paritytech/substrate", branch = "master
 futures-timer = "3.0.2"
 assert_matches = "1.4.0"
 maplit = "1.0"
-smallvec = "1.6.1"

polkadot/node/network/availability-distribution/src/tests/state.rs

@@ -18,7 +18,6 @@ use std::{collections::{HashMap, HashSet}, sync::Arc, time::Duration};
 
 use polkadot_node_subsystem_util::TimeoutExt;
 use polkadot_subsystem_testhelpers::TestSubsystemContextHandle;
-use smallvec::smallvec;
 
 use futures::{FutureExt, channel::oneshot, SinkExt, channel::mpsc, StreamExt};
 use futures_timer::Delay;
@@ -171,13 +170,13 @@ impl TestState {
 			self
 			.relay_chain.iter().zip(advanced)
 			.map(|(old, new)| ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
+				activated: Some(ActivatedLeaf {
 					hash: new.clone(),
 					number: 1,
 					status: LeafStatus::Fresh,
 					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![old.clone()],
+				}),
+				deactivated: vec![old.clone()].into(),
 			}).collect::<Vec<_>>()
 		};
 

polkadot/node/network/availability-recovery/Cargo.toml

@@ -24,7 +24,6 @@ assert_matches = "1.4.0"
 env_logger = "0.8.4"
 futures-timer = "3.0.2"
 log = "0.4.11"
-smallvec = "1.5.1"
 
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/network/availability-recovery/src/tests.rs

@@ -20,7 +20,6 @@ use std::sync::Arc;
 use futures::{executor, future};
 use futures_timer::Delay;
 use assert_matches::assert_matches;
-use smallvec::smallvec;
 
 use parity_scale_codec::Encode;
 
@@ -446,15 +445,12 @@ fn availability_is_recovered_from_chunks_if_no_group_provided() {
 	test_harness_fast_path(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -528,15 +524,12 @@ fn availability_is_recovered_from_chunks_even_if_backing_group_supplied_if_chunk
 	test_harness_chunks_only(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -610,15 +603,12 @@ fn bad_merkle_path_leads_to_recovery_error() {
 	test_harness_fast_path(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -667,15 +657,12 @@ fn wrong_chunk_index_leads_to_recovery_error() {
 	test_harness_fast_path(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -741,15 +728,12 @@ fn invalid_erasure_coding_leads_to_invalid_error() {
 
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -789,15 +773,12 @@ fn fast_path_backing_group_recovers() {
 	test_harness_fast_path(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -842,15 +823,12 @@ fn no_answers_in_fast_path_causes_chunk_requests() {
 	test_harness_fast_path(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -905,15 +883,12 @@ fn task_canceled_when_receivers_dropped() {
 	test_harness_chunks_only(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, _) = oneshot::channel();
@@ -948,15 +923,12 @@ fn chunks_retry_until_all_nodes_respond() {
 	test_harness_chunks_only(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -1007,15 +979,12 @@ fn returns_early_if_we_have_the_data() {
 	test_harness_chunks_only(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();
@@ -1045,15 +1014,12 @@ fn does_not_query_local_validator() {
 	test_harness_chunks_only(|mut virtual_overseer| async move {
 		overseer_signal(
 			&mut virtual_overseer,
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: smallvec![ActivatedLeaf {
-					hash: test_state.current.clone(),
-					number: 1,
-					status: LeafStatus::Fresh,
-					span: Arc::new(jaeger::Span::Disabled),
-				}],
-				deactivated: smallvec![],
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: test_state.current.clone(),
+				number: 1,
+				status: LeafStatus::Fresh,
+				span: Arc::new(jaeger::Span::Disabled),
+			})),
 		).await;
 
 		let (tx, rx) = oneshot::channel();

polkadot/node/network/bridge/src/lib.rs

@@ -401,7 +401,7 @@ where
 					tracing::trace!(
 						target: LOG_TARGET,
 						action = "ActiveLeaves",
-						num_activated = %activated.len(),
+						has_activated = activated.is_some(),
 						num_deactivated = %deactivated.len(),
 					);
 

polkadot/node/network/bridge/src/tests.rs

@@ -1336,31 +1336,22 @@ fn our_view_updates_decreasing_order_and_limited_to_max() {
 
 		// to show that we're still connected on the collation protocol, send a view update.
 
-		let hashes = (0..MAX_VIEW_HEADS * 3).map(|i| Hash::repeat_byte(i as u8));
+		let hashes = (0..MAX_VIEW_HEADS + 1).map(|i| Hash::repeat_byte(i as u8));
 
-		virtual_overseer.send(
-			FromOverseer::Signal(OverseerSignal::ActiveLeaves(
-				// These are in reverse order, so the subsystem must sort internally to
-				// get the correct view.
-				ActiveLeavesUpdate {
-					activated: hashes.enumerate().map(|(i, h)| ActivatedLeaf {
-						hash: h,
+		for (i, hash) in hashes.enumerate().rev() {
+			// These are in reverse order, so the subsystem must sort internally to
+			// get the correct view.
+			virtual_overseer.send(
+				FromOverseer::Signal(OverseerSignal::ActiveLeaves(
+					ActiveLeavesUpdate::start_work(ActivatedLeaf {
+						hash,
 						number: i as _,
 						status: LeafStatus::Fresh,
 						span: Arc::new(jaeger::Span::Disabled),
-					}).rev().collect(),
-					deactivated: Default::default(),
-				}
-			))
-		).await;
-
-		let view_heads = (MAX_VIEW_HEADS * 2 .. MAX_VIEW_HEADS * 3).rev()
-			.map(|i| (Hash::repeat_byte(i as u8), Arc::new(jaeger::Span::Disabled)) );
-
-		let our_view = OurView::new(
-			view_heads,
-			0,
-		);
+					}),
+				))
+			).await;
+		}
 
 		assert_matches!(
 			virtual_overseer.recv().await,
@@ -1375,15 +1366,26 @@ fn our_view_updates_decreasing_order_and_limited_to_max() {
 			)
 		);
 
-		assert_sends_validation_event_to_all(
-			NetworkBridgeEvent::OurViewChange(our_view.clone()),
-			&mut virtual_overseer,
-		).await;
+		let our_views = (1..=MAX_VIEW_HEADS).rev()
+			.map(|start| OurView::new(
+				(start..=MAX_VIEW_HEADS)
+					.rev()
+					.map(|i| (Hash::repeat_byte(i as u8), Arc::new(jaeger::Span::Disabled))),
+				0,
+			));
+
+		for our_view in our_views {
+			assert_sends_validation_event_to_all(
+				NetworkBridgeEvent::OurViewChange(our_view.clone()),
+				&mut virtual_overseer,
+			).await;
+
+			assert_sends_collation_event_to_all(
+				NetworkBridgeEvent::OurViewChange(our_view),
+				&mut virtual_overseer,
+			).await;
+		}
 
-		assert_sends_collation_event_to_all(
-			NetworkBridgeEvent::OurViewChange(our_view),
-			&mut virtual_overseer,
-		).await;
 		virtual_overseer
 	});
 }

polkadot/node/network/collator-protocol/src/collator_side/tests.rs

@@ -286,15 +286,12 @@ async fn setup_system(virtual_overseer: &mut VirtualOverseer, test_state: &TestS
 
 	overseer_signal(
 		virtual_overseer,
-		OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
-				hash: test_state.relay_parent,
-				number: 1,
-				status: LeafStatus::Fresh,
-				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: [][..].into(),
-		}),
+		OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+			hash: test_state.relay_parent,
+			number: 1,
+			status: LeafStatus::Fresh,
+			span: Arc::new(jaeger::Span::Disabled),
+		})),
 	).await;
 
 	overseer_send(
@@ -579,7 +576,7 @@ fn advertise_and_send_collation() {
 			assert_matches!(
 				overseer_recv(&mut virtual_overseer).await,
 				AllMessages::NetworkBridge(NetworkBridgeMessage::ReportPeer(bad_peer, _)) => {
-					assert_eq!(bad_peer, peer); 
+					assert_eq!(bad_peer, peer);
 				}
 			);
 			assert_matches!(

polkadot/node/network/dispute-distribution/src/tests/mod.rs

@@ -615,16 +615,14 @@ async fn activate_leaf(
 	handle.send(FromOverseer::Signal(
 		OverseerSignal::ActiveLeaves(
 			ActiveLeavesUpdate {
-				activated: [ActivatedLeaf {
-						hash: activate,
-						number: 10,
-						status: LeafStatus::Fresh,
-						span: Arc::new(Span::Disabled),
-					}][..]
-				   .into(),
+				activated: Some(ActivatedLeaf {
+					hash: activate,
+					number: 10,
+					status: LeafStatus::Fresh,
+					span: Arc::new(Span::Disabled),
+				}),
 				deactivated: deactivate.into_iter().collect(),
 			}
-
 	)))
 	.await;
 	assert_matches!(

polkadot/node/network/statement-distribution/src/tests.rs

@@ -652,15 +652,14 @@ fn receiving_from_one_sends_to_another_and_to_candidate_backing() {
 
 	let test_fut = async move {
 		// register our active heads.
-		handle.send(FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
+		handle.send(FromOverseer::Signal(
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
 				hash: hash_a,
 				number: 1,
 				status: LeafStatus::Fresh,
 				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: vec![].into(),
-		}))).await;
+			})),
+		)).await;
 
 		assert_matches!(
 			handle.recv().await,
@@ -828,15 +827,14 @@ fn receiving_large_statement_from_one_sends_to_another_and_to_candidate_backing(
 		}).await;
 
 		// register our active heads.
-		handle.send(FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
+		handle.send(FromOverseer::Signal(
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
 				hash: hash_a,
 				number: 1,
 				status: LeafStatus::Fresh,
 				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: vec![].into(),
-		}))).await;
+			})),
+		)).await;
 
 		assert_matches!(
 			handle.recv().await,
@@ -1300,15 +1298,14 @@ fn share_prioritizes_backing_group() {
 		}).await;
 
 		// register our active heads.
-		handle.send(FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
+		handle.send(FromOverseer::Signal(
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
 				hash: hash_a,
 				number: 1,
 				status: LeafStatus::Fresh,
 				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: vec![].into(),
-		}))).await;
+			})),
+		)).await;
 
 		assert_matches!(
 			handle.recv().await,
@@ -1556,15 +1553,14 @@ fn peer_cant_flood_with_large_statements() {
 		}).await;
 
 		// register our active heads.
-		handle.send(FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-			activated: vec![ActivatedLeaf {
+		handle.send(FromOverseer::Signal(
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
 				hash: hash_a,
 				number: 1,
 				status: LeafStatus::Fresh,
 				span: Arc::new(jaeger::Span::Disabled),
-			}].into(),
-			deactivated: vec![].into(),
-		}))).await;
+			})),
+		)).await;
 
 		assert_matches!(
 			handle.recv().await,

polkadot/node/overseer/src/lib.rs

@@ -706,31 +706,27 @@ where
 	/// Stop the overseer.
 	async fn stop(mut self) {
 		let _ = self.wait_terminate(
-				OverseerSignal::Conclude,
-				::std::time::Duration::from_secs(1_u64)
-			).await;
+			OverseerSignal::Conclude,
+			Duration::from_secs(1_u64)
+		).await;
 	}
 
 	/// Run the `Overseer`.
 	pub async fn run(mut self) -> SubsystemResult<()> {
-		let mut update = ActiveLeavesUpdate::default();
-
+		// Notify about active leaves on startup before starting the loop
 		for (hash, number) in std::mem::take(&mut self.leaves) {
 			let _ = self.active_leaves.insert(hash, number);
 			if let Some((span, status)) = self.on_head_activated(&hash, None) {
-				update.activated.push(ActivatedLeaf {
+				let update = ActiveLeavesUpdate::start_work(ActivatedLeaf {
 					hash,
 					number,
 					status,
 					span,
 				});
+				self.broadcast_signal(OverseerSignal::ActiveLeaves(update)).await?;
 			}
 		}
 
-		if !update.is_empty() {
-			self.broadcast_signal(OverseerSignal::ActiveLeaves(update)).await?;
-		}
-
 		loop {
 			select! {
 				msg = self.events_rx.select_next_some() => {

polkadot/node/overseer/src/tests.rs

@@ -427,21 +427,21 @@ fn overseer_start_stop_works() {
 				status: LeafStatus::Fresh,
 			})),
 			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: [ActivatedLeaf {
+				activated: Some(ActivatedLeaf {
 					hash: second_block_hash,
 					number: 2,
 					span: Arc::new(jaeger::Span::Disabled),
 					status: LeafStatus::Fresh,
-				}].as_ref().into(),
+				}),
 				deactivated: [first_block_hash].as_ref().into(),
 			}),
 			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: [ActivatedLeaf {
+				activated: Some(ActivatedLeaf {
 					hash: third_block_hash,
 					number: 3,
 					span: Arc::new(jaeger::Span::Disabled),
 					status: LeafStatus::Fresh,
-				}].as_ref().into(),
+				}),
 				deactivated: [second_block_hash].as_ref().into(),
 			}),
 		];
@@ -530,23 +530,18 @@ fn overseer_finalize_works() {
 		handle.block_finalized(third_block).await;
 
 		let expected_heartbeats = vec![
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: [
-					ActivatedLeaf {
-						hash: first_block_hash,
-						number: 1,
-						span: Arc::new(jaeger::Span::Disabled),
-						status: LeafStatus::Fresh,
-					},
-					ActivatedLeaf {
-						hash: second_block_hash,
-						number: 2,
-						span: Arc::new(jaeger::Span::Disabled),
-						status: LeafStatus::Fresh,
-					},
-				].as_ref().into(),
-				..Default::default()
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: first_block_hash,
+				number: 1,
+				span: Arc::new(jaeger::Span::Disabled),
+				status: LeafStatus::Fresh,
+			})),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: second_block_hash,
+				number: 2,
+				span: Arc::new(jaeger::Span::Disabled),
+				status: LeafStatus::Fresh,
+			})),
 			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
 				deactivated: [first_block_hash, second_block_hash].as_ref().into(),
 				..Default::default()
@@ -630,17 +625,12 @@ fn do_not_send_empty_leaves_update_on_block_finalization() {
 		handle.block_imported(imported_block.clone()).await;
 
 		let expected_heartbeats = vec![
-			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-				activated: [
-					ActivatedLeaf {
-						hash: imported_block.hash,
-						number: imported_block.number,
-						span: Arc::new(jaeger::Span::Disabled),
-						status: LeafStatus::Fresh,
-					}
-				].as_ref().into(),
-				..Default::default()
-			}),
+			OverseerSignal::ActiveLeaves(ActiveLeavesUpdate::start_work(ActivatedLeaf {
+				hash: imported_block.hash,
+				number: imported_block.number,
+				span: Arc::new(jaeger::Span::Disabled),
+				status: LeafStatus::Fresh,
+			})),
 			OverseerSignal::BlockFinalized(finalized_block.hash, 1),
 		];
 

polkadot/node/subsystem-types/src/lib.rs

@@ -90,8 +90,8 @@ pub struct ActivatedLeaf {
 /// Note that the activated and deactivated fields indicate deltas, not complete sets.
 #[derive(Clone, Default)]
 pub struct ActiveLeavesUpdate {
-	/// New relay chain blocks of interest.
-	pub activated: SmallVec<[ActivatedLeaf; ACTIVE_LEAVES_SMALLVEC_CAPACITY]>,
+	/// New relay chain block of interest.
+	pub activated: Option<ActivatedLeaf>,
 	/// Relay chain block hashes no longer of interest.
 	pub deactivated: SmallVec<[Hash; ACTIVE_LEAVES_SMALLVEC_CAPACITY]>,
 }
@@ -99,7 +99,7 @@ pub struct ActiveLeavesUpdate {
 impl ActiveLeavesUpdate {
 	/// Create a `ActiveLeavesUpdate` with a single activated hash
 	pub fn start_work(activated: ActivatedLeaf) -> Self {
-		Self { activated: [activated][..].into(), ..Default::default() }
+		Self { activated: Some(activated), ..Default::default() }
 	}
 
 	/// Create a `ActiveLeavesUpdate` with a single deactivated hash
@@ -109,7 +109,7 @@ impl ActiveLeavesUpdate {
 
 	/// Is this update empty and doesn't contain any information?
 	pub fn is_empty(&self) -> bool {
-		self.activated.is_empty() && self.deactivated.is_empty()
+		self.activated.is_none() && self.deactivated.is_empty()
 	}
 }
 
@@ -118,23 +118,16 @@ impl PartialEq for ActiveLeavesUpdate {
 	///
 	/// Instead, it means equality when `activated` and `deactivated` are considered as sets.
 	fn eq(&self, other: &Self) -> bool {
-		self.activated.len() == other.activated.len() && self.deactivated.len() == other.deactivated.len()
-			&& self.activated.iter().all(|a| other.activated.iter().any(|o| a.hash == o.hash))
+		self.activated.as_ref().map(|a| a.hash) == other.activated.as_ref().map(|a| a.hash)
+			&& self.deactivated.len() == other.deactivated.len()
 			&& self.deactivated.iter().all(|a| other.deactivated.contains(a))
 	}
 }
 
 impl fmt::Debug for ActiveLeavesUpdate {
 	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-		struct Activated<'a>(&'a [ActivatedLeaf]);
-		impl fmt::Debug for Activated<'_> {
-			fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-				f.debug_list().entries(self.0.iter().map(|e| e.hash)).finish()
-			}
-		}
-
 		f.debug_struct("ActiveLeavesUpdate")
-			.field("activated", &Activated(&self.activated))
+			.field("activated", &self.activated)
 			.field("deactivated", &self.deactivated)
 			.finish()
 	}