Remove Parent Hash to Session mapping (#928)

* Adds a SigningContext type

* Bump spec versions

* Fixes requested changes

* Bump ParachainHost api_version and guard signing_context call

* Improve error message

* If there is no signing_context api use default value

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

polkadot/network/src/protocol/mod.rs

@@ -162,7 +162,6 @@ impl NetworkServiceOps for PolkadotNetworkService {
 trait GossipOps: Clone + Send + crate::legacy::GossipService + 'static {
 	fn new_local_leaf(
 		&self,
-		relay_parent: Hash,
 		validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions;
 
@@ -177,10 +176,12 @@ trait GossipOps: Clone + Send + crate::legacy::GossipService + 'static {
 impl GossipOps for RegisteredMessageValidator {
 	fn new_local_leaf(
 		&self,
-		relay_parent: Hash,
 		validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions {
-		RegisteredMessageValidator::new_local_leaf(self, relay_parent, validation_data)
+		RegisteredMessageValidator::new_local_leaf(
+			self,
+			validation_data,
+		)
 	}
 
 	fn register_availability_store(
@@ -804,7 +805,6 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 		authorities: Vec<ValidatorId>,
 	) {
 		// glue: let gossip know about our new local leaf.
-		let relay_parent = table.consensus_parent_hash().clone();
 		let (signal, exit) = exit_future::signal();
 
 		let key = table.session_key();
@@ -814,19 +814,20 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 			}
 		}
 
+		let signing_context = table.signing_context().clone();
+		let relay_parent = signing_context.parent_hash.clone();
 		let new_leaf_actions = self.gossip_handle.new_local_leaf(
-			relay_parent,
-			crate::legacy::gossip::MessageValidationData { authorities },
+			crate::legacy::gossip::MessageValidationData { authorities, signing_context },
 		);
 
 		new_leaf_actions.perform(&self.gossip_handle);
 
 		self.protocol_handler.consensus_instances.insert(
-			relay_parent,
+			relay_parent.clone(),
 			ConsensusNetworkingInstance {
 				statement_table: table.clone(),
-				relay_parent,
-				attestation_topic: crate::legacy::gossip::attestation_topic(relay_parent),
+				relay_parent: relay_parent.clone(),
+				attestation_topic: crate::legacy::gossip::attestation_topic(relay_parent.clone()),
 				_drop_signal: signal,
 			},
 		);
@@ -1324,7 +1325,7 @@ impl ParachainNetwork for Service {
 	) -> Self::BuildTableRouter {
 		let authorities = authorities.to_vec();
 		let mut sender = self.sender.clone();
-		let relay_parent = table.consensus_parent_hash().clone();
+		let relay_parent = table.signing_context().parent_hash.clone();
 
 		Box::pin(async move {
 			sender.send(

polkadot/network/src/protocol/tests.rs

@@ -20,7 +20,7 @@ use polkadot_primitives::{Block, Header, BlockId};
 use polkadot_primitives::parachain::{
 	Id as ParaId, Chain, DutyRoster, ParachainHost, ValidatorId,
 	Retriable, CollatorId, AbridgedCandidateReceipt,
-	GlobalValidationSchedule, LocalValidationData, ErasureChunk,
+	GlobalValidationSchedule, LocalValidationData, ErasureChunk, SigningContext,
 };
 use polkadot_validation::SharedTable;
 
@@ -114,7 +114,6 @@ impl crate::legacy::GossipService for MockGossip {
 impl GossipOps for MockGossip {
 	fn new_local_leaf(
 		&self,
-		_relay_parent: Hash,
 		_validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions {
 		crate::legacy::gossip::NewLeafActions::new()
@@ -294,6 +293,22 @@ impl ParachainHost<Block> for RuntimeApi {
 	) -> ClientResult<NativeOrEncoded<Option<Vec<AbridgedCandidateReceipt>>>> {
 		Ok(NativeOrEncoded::Native(Some(Vec::new())))
 	}
+
+	fn ParachainHost_signing_context_runtime_api_impl(
+		&self,
+		_at: &BlockId,
+		_: ExecutionContext,
+		_: Option<()>,
+		_: Vec<u8>,
+	) -> ClientResult<NativeOrEncoded<SigningContext>> {
+		Ok(NativeOrEncoded::Native(
+				SigningContext {
+					session_index: Default::default(),
+					parent_hash: Default::default(),
+				}
+			)
+		)
+	}
 }
 
 impl super::Service {
@@ -389,11 +404,15 @@ fn consensus_instances_cleaned_up() {
 	let relay_parent = [0; 32].into();
 	let authorities = Vec::new();
 
+	let signing_context = SigningContext {
+		session_index: Default::default(),
+		parent_hash: relay_parent,
+	};
 	let table = Arc::new(SharedTable::new(
 		Vec::new(),
 		HashMap::new(),
 		None,
-		relay_parent,
+		signing_context,
 		AvailabilityStore::new_in_memory(service.clone()),
 		None,
 	));