Accept an advertisement if there is a free spot for it at at least on…

…e fork

polkadot/node/network/collator-protocol/src/validator_side/mod.rs

@@ -1065,30 +1065,45 @@ fn ensure_seconding_limit_is_respected(
 		"Checking seconding limit",
 	);
 
+	let mut has_claim_at_some_path = false;
 	for path in paths {
 		let mut cq_state = ClaimQueueState::new();
-		for ancestor in path {
+		for ancestor in &path {
 			let seconded_and_pending = state.seconded_and_pending_for_para(&ancestor, &para_id);
 			cq_state.add_leaf(
 				&ancestor,
 				&state
 					.per_relay_parent
-					.get(&ancestor)
+					.get(ancestor)
 					.ok_or(AdvertisementError::RelayParentUnknown)?
 					.assignment
 					.current,
 			);
 			for _ in 0..seconded_and_pending {
-				cq_state.claim_at(&ancestor, &para_id);
+				cq_state.claim_at(ancestor, &para_id);
 			}
 		}
 
-		if !cq_state.can_claim_at(relay_parent, &para_id) {
-			return Err(AdvertisementError::SecondedLimitReached)
+		if cq_state.can_claim_at(relay_parent, &para_id) {
+			gum::trace!(
+				target: LOG_TARGET,
+				?relay_parent,
+				?para_id,
+				?path,
+				"Seconding limit respected at path",
+			);
+			has_claim_at_some_path = true;
+			break
 		}
 	}
 
-	Ok(())
+	// If there is a place in the claim queue for the candidate at at least one path we will accept
+	// it.
+	if has_claim_at_some_path {
+		Ok(())
+	} else {
+		Err(AdvertisementError::SecondedLimitReached)
+	}
 }
 
 async fn handle_advertisement<Sender>(

polkadot/node/network/collator-protocol/src/validator_side/tests/prospective_parachains.rs

@@ -2286,20 +2286,15 @@ fn claims_above_are_counted_correctly() {
 	test_harness(ReputationAggregator::new(|_| true), |test_harness| async move {
 		let TestHarness { mut virtual_overseer, keystore } = test_harness;
 
-		let hash_a = Hash::from_low_u64_be(test_state.relay_parent.to_low_u64_be() - 1);
-		let hash_b = Hash::from_low_u64_be(hash_a.to_low_u64_be() - 1);
-		let hash_c = Hash::from_low_u64_be(hash_b.to_low_u64_be() - 1);
+		let hash_a = Hash::from_low_u64_be(test_state.relay_parent.to_low_u64_be() - 1); // block 0
+		let hash_b = Hash::from_low_u64_be(hash_a.to_low_u64_be() - 1); // block 1
+		let hash_c = Hash::from_low_u64_be(hash_b.to_low_u64_be() - 1); // block 2
 
 		let pair_a = CollatorPair::generate().0;
 		let collator_a = PeerId::random();
 		let para_id_a = test_state.chain_ids[0];
 
-		update_view(
-			&mut virtual_overseer,
-			&mut test_state,
-			vec![(hash_a, 0), (hash_b, 1), (hash_c, 2)],
-		)
-		.await;
+		update_view(&mut virtual_overseer, &mut test_state, vec![(hash_c, 2)]).await;
 
 		connect_and_declare_collator(
 			&mut virtual_overseer,
@@ -2397,20 +2392,15 @@ fn claim_fills_last_free_slot() {
 	test_harness(ReputationAggregator::new(|_| true), |test_harness| async move {
 		let TestHarness { mut virtual_overseer, keystore } = test_harness;
 
-		let hash_a = Hash::from_low_u64_be(test_state.relay_parent.to_low_u64_be() - 1);
-		let hash_b = Hash::from_low_u64_be(hash_a.to_low_u64_be() - 1);
-		let hash_c = Hash::from_low_u64_be(hash_b.to_low_u64_be() - 1);
+		let hash_a = Hash::from_low_u64_be(test_state.relay_parent.to_low_u64_be() - 1); // block 0
+		let hash_b = Hash::from_low_u64_be(hash_a.to_low_u64_be() - 1); // block 1
+		let hash_c = Hash::from_low_u64_be(hash_b.to_low_u64_be() - 1); // block 2
 
 		let pair_a = CollatorPair::generate().0;
 		let collator_a = PeerId::random();
 		let para_id_a = test_state.chain_ids[0];
 
-		update_view(
-			&mut virtual_overseer,
-			&mut test_state,
-			vec![(hash_a, 0), (hash_b, 1), (hash_c, 2)],
-		)
-		.await;
+		update_view(&mut virtual_overseer, &mut test_state, vec![(hash_c, 2)]).await;
 
 		connect_and_declare_collator(
 			&mut virtual_overseer,
@@ -2432,25 +2422,25 @@ fn claim_fills_last_free_slot() {
 		)
 		.await;
 
-		// Collation at hash_c claims its own spot
+		// Collation at hash_b claims its own spot
 		submit_second_and_assert(
 			&mut virtual_overseer,
 			keystore.clone(),
 			ParaId::from(test_state.chain_ids[0]),
-			hash_c,
+			hash_b,
 			collator_a,
-			HeadData(vec![2u8]),
+			HeadData(vec![3u8]),
 		)
 		.await;
 
-		// Collation at hash_b claims its own spot
+		// Collation at hash_c claims its own spot
 		submit_second_and_assert(
 			&mut virtual_overseer,
 			keystore.clone(),
 			ParaId::from(test_state.chain_ids[0]),
-			hash_b,
+			hash_c,
 			collator_a,
-			HeadData(vec![3u8]),
+			HeadData(vec![2u8]),
 		)
 		.await;