Collation Generation - ready for old relay parents

cumulus/client/consensus/aura/src/collators/lookahead.rs

@@ -317,6 +317,23 @@ where
 				},
 			};
 
+			let session_index = match params
+				.relay_client
+				.session_index_for_child(relay_parent)
+				.await
+			{
+				Ok(session_index) => session_index,
+				Err(err) => {
+					tracing::error!(
+						target: crate::LOG_TARGET,
+						?err,
+						?relay_parent,
+						"Failed to fetch session index."
+					);
+					continue;
+				},
+			};
+
 			let parent_search_result = match crate::collators::find_parent(
 				relay_parent,
 				params.para_id,
@@ -501,11 +518,12 @@ where
 									SubmitCollationParams {
 										relay_parent,
 										collation,
-										parent_head: parent_header.encode().into(),
 										validation_code_hash,
 										result_sender: None,
 										core_index,
 										scheduling_parent: None,
+										session_index,
+										validation_data,
 									},
 								),
 								"SubmitCollation",

cumulus/client/consensus/aura/src/collators/slot_based/block_builder_task.rs

@@ -474,7 +474,7 @@ where
 				parachain_candidate: candidate.into(),
 				validation_code_hash,
 				core_index: core.core_index(),
-				max_pov_size: validation_data.max_pov_size,
+				validation_data,
 			}) {
 				tracing::error!(target: crate::LOG_TARGET, ?err, "Unable to send block to collation task.");
 				return;

cumulus/client/consensus/aura/src/collators/slot_based/collation_task.rs

@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU General Public License
 // along with Cumulus. If not, see <https://www.gnu.org/licenses/>.
 
-use codec::Encode;
 use std::path::PathBuf;
 
 use cumulus_client_collator::service::ServiceInterface as CollatorServiceInterface;
@@ -126,7 +125,7 @@ async fn handle_collation_message<Block: BlockT, RClient: RelayChainInterface +
 		validation_code_hash,
 		relay_parent,
 		core_index,
-		max_pov_size,
+		validation_data,
 	} = message;
 
 	let hash = parachain_candidate.block.header().hash();
@@ -156,7 +155,7 @@ async fn handle_collation_message<Block: BlockT, RClient: RelayChainInterface +
 						parent_header.clone(),
 						relay_parent_header.state_root,
 						relay_parent_header.number,
-						max_pov_size,
+						validation_data.max_pov_size,
 					);
 				}
 			} else {
@@ -171,18 +170,32 @@ async fn handle_collation_message<Block: BlockT, RClient: RelayChainInterface +
 		);
 	}
 
+	let session_index = match relay_client.session_index_for_child(relay_parent).await {
+		Ok(session_index) => session_index,
+		Err(err) => {
+			tracing::error!(
+				target: LOG_TARGET,
+				?err,
+				?relay_parent,
+				"Failed to fetch session index."
+			);
+			return;
+		},
+	};
+
 	tracing::debug!(target: LOG_TARGET, ?core_index, ?hash, %number, "Submitting collation for core.");
 
 	overseer_handle
 		.send_msg(
 			CollationGenerationMessage::SubmitCollation(SubmitCollationParams {
 				relay_parent,
 				collation,
-				parent_head: parent_header.encode().into(),
 				validation_code_hash,
 				core_index,
 				result_sender: None,
 				scheduling_parent: None,
+				session_index,
+				validation_data,
 			}),
 			"SubmitCollation",
 		)

cumulus/client/consensus/aura/src/collators/slot_based/mod.rs

@@ -77,7 +77,8 @@ use cumulus_primitives_core::{KeyToIncludeInRelayProof, RelayParentOffsetApi};
 use cumulus_relay_chain_interface::RelayChainInterface;
 use futures::FutureExt;
 use polkadot_primitives::{
-	CollatorPair, CoreIndex, Hash as RelayHash, Id as ParaId, ValidationCodeHash,
+	CollatorPair, CoreIndex, Hash as RelayHash, Id as ParaId, PersistedValidationData,
+	ValidationCodeHash,
 };
 use sc_client_api::{backend::AuxStore, BlockBackend, BlockOf, UsageProvider};
 use sc_consensus::BlockImport;
@@ -267,6 +268,6 @@ struct CollatorMessage<Block: BlockT> {
 	pub validation_code_hash: ValidationCodeHash,
 	/// Core index that this block should be submitted on
 	pub core_index: CoreIndex,
-	/// Maximum pov size. Currently needed only for exporting PoV.
-	pub max_pov_size: u32,
+	/// The persisted validation data for this collation.
+	pub validation_data: PersistedValidationData,
 }

polkadot/node/collation-generation/src/lib.rs

@@ -229,44 +229,28 @@ impl CollationGenerationSubsystem {
 		let SubmitCollationParams {
 			relay_parent,
 			collation,
-			parent_head,
 			validation_code_hash,
 			result_sender,
 			core_index,
 			scheduling_parent,
+			session_index,
+			validation_data,
 		} = params;
 
-		let mut validation_data = match request_persisted_validation_data(
-			relay_parent,
-			config.para_id,
-			OccupiedCoreAssumption::TimedOut,
-			ctx.sender(),
-		)
-		.await
-		.await??
-		{
-			Some(v) => v,
-			None => {
-				gum::debug!(
-					target: LOG_TARGET,
-					relay_parent = ?relay_parent,
-					our_para = %config.para_id,
-					"No validation data for para - does it exist at this relay-parent?",
-				);
-				return Ok(());
-			},
-		};
-
-		// We need to swap the parent-head data, but all other fields here will be correct.
-		validation_data.parent_head = parent_head;
-
-		let claim_queue = request_claim_queue(relay_parent, ctx.sender()).await.await??;
+		// For V2 descriptors, scheduling_parent is None and relay_parent serves both roles.
+		let scheduling_parent_or_relay = scheduling_parent.unwrap_or(relay_parent);
+		let claim_queue =
+			request_claim_queue(scheduling_parent_or_relay, ctx.sender()).await.await??;
 
-		let session_index =
-			request_session_index_for_child(relay_parent, ctx.sender()).await.await??;
+		let scheduling_session =
+			request_session_index_for_child(scheduling_parent_or_relay, ctx.sender())
+				.await
+				.await??;
 
-		let session_info =
-			self.session_info_cache.get(relay_parent, session_index, ctx.sender()).await?;
+		let session_info = self
+			.session_info_cache
+			.get(scheduling_parent_or_relay, scheduling_session, ctx.sender())
+			.await?;
 		let collation = PreparedCollation {
 			collation,
 			relay_parent,
@@ -276,6 +260,7 @@ impl CollationGenerationSubsystem {
 			n_validators: session_info.n_validators,
 			core_index,
 			session_index,
+			scheduling_session,
 		};
 
 		construct_and_distribute_receipt(
@@ -300,7 +285,7 @@ impl CollationGenerationSubsystem {
 			return Ok(());
 		};
 
-		let Some(relay_parent) = maybe_activated else { return Ok(()) };
+		let Some(activated) = maybe_activated else { return Ok(()) };
 
 		// If there is no collation function provided, bail out early.
 		// Important: Lookahead collator and slot based collator do not use `CollatorFn`.
@@ -313,14 +298,14 @@ impl CollationGenerationSubsystem {
 		let _timer = self.metrics.time_new_activation();
 
 		let session_index =
-			request_session_index_for_child(relay_parent, ctx.sender()).await.await??;
+			request_session_index_for_child(activated, ctx.sender()).await.await??;
 
 		let session_info =
-			self.session_info_cache.get(relay_parent, session_index, ctx.sender()).await?;
+			self.session_info_cache.get(activated, session_index, ctx.sender()).await?;
 		let n_validators = session_info.n_validators;
 
 		let claim_queue =
-			ClaimQueueSnapshot::from(request_claim_queue(relay_parent, ctx.sender()).await.await??);
+			ClaimQueueSnapshot::from(request_claim_queue(activated, ctx.sender()).await.await??);
 
 		let assigned_cores = claim_queue
 			.iter_all_claims()
@@ -338,7 +323,7 @@ impl CollationGenerationSubsystem {
 		// for some more blocks, or even time out. We assume all cores are being freed.
 
 		let mut validation_data = match request_persisted_validation_data(
-			relay_parent,
+			activated,
 			para_id,
 			// Just use included assumption always. If there are no pending candidates it's a
 			// no-op.
@@ -352,7 +337,7 @@ impl CollationGenerationSubsystem {
 			None => {
 				gum::debug!(
 					target: LOG_TARGET,
-					relay_parent = ?relay_parent,
+					relay_parent = ?activated,
 					our_para = %para_id,
 					"validation data is not available",
 				);
@@ -361,7 +346,7 @@ impl CollationGenerationSubsystem {
 		};
 
 		let validation_code_hash = match request_validation_code_hash(
-			relay_parent,
+			activated,
 			para_id,
 			// Just use included assumption always. If there are no pending candidates it's a
 			// no-op.
@@ -375,7 +360,7 @@ impl CollationGenerationSubsystem {
 			None => {
 				gum::debug!(
 					target: LOG_TARGET,
-					relay_parent = ?relay_parent,
+					relay_parent = ?activated,
 					our_para = %para_id,
 					"validation code hash is not found.",
 				);
@@ -403,7 +388,7 @@ impl CollationGenerationSubsystem {
 					};
 
 					let (collation, result_sender) =
-						match collator_fn(relay_parent, &validation_data).await {
+						match collator_fn(activated, &validation_data).await {
 							Some(collation) => collation.into_inner(),
 							None => {
 								gum::debug!(
@@ -486,12 +471,14 @@ impl CollationGenerationSubsystem {
 						PreparedCollation {
 							collation,
 							para_id,
-							relay_parent,
+							relay_parent: activated,
 							validation_data: validation_data.clone(),
 							validation_code_hash,
 							n_validators,
 							core_index: descriptor_core_index,
 							session_index,
+							// V2 only: relay_parent == scheduling_parent, same session.
+							scheduling_session: session_index,
 						},
 						&mut task_sender,
 						result_sender,
@@ -572,7 +559,10 @@ struct PreparedCollation {
 	validation_code_hash: ValidationCodeHash,
 	n_validators: usize,
 	core_index: CoreIndex,
+	/// The relay parent's session index.
 	session_index: SessionIndex,
+	/// The scheduling parent's session index.
+	scheduling_session: SessionIndex,
 }
 
 /// Takes a prepared collation, along with its context, and produces a candidate receipt
@@ -594,6 +584,7 @@ async fn construct_and_distribute_receipt(
 		n_validators,
 		core_index,
 		session_index,
+		scheduling_session,
 	} = collation;
 
 	let persisted_validation_data_hash = validation_data.hash();
@@ -641,6 +632,7 @@ async fn construct_and_distribute_receipt(
 				relay_parent,
 				core_index,
 				session_index,
+				scheduling_session,
 				persisted_validation_data_hash,
 				pov_hash,
 				erasure_root,