companion for paritytech/polkadot#6161

client/relay-chain-minimal-node/src/blockchain_rpc_client.rs

@@ -261,6 +261,17 @@ impl RuntimeApiSubsystemClient for BlockChainRpcClient {
 		Ok(self.rpc_client.parachain_host_session_info_before_version_2(at, index).await?)
 	}
 
+	async fn session_executor_params(
+		&self,
+		at: Hash,
+		session_index: polkadot_primitives::SessionIndex,
+	) -> Result<Option<polkadot_primitives::vstaging::ExecutorParams>, sp_api::ApiError> {
+		Ok(self
+			.rpc_client
+			.parachain_host_session_executor_params(at, session_index)
+			.await?)
+	}
+
 	async fn submit_pvf_check_statement(
 		&self,
 		at: Hash,

client/relay-chain-rpc-interface/src/rpc_client.rs

@@ -17,11 +17,11 @@
 use crate::reconnecting_ws_client::ReconnectingWsClient;
 use cumulus_primitives_core::{
 	relay_chain::{
-		CandidateCommitments, CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState,
-		DisputeState, GroupRotationInfo, Hash as RelayHash, Header as RelayHeader,
-		InboundHrmpMessage, OccupiedCoreAssumption, OldV1SessionInfo, PvfCheckStatement,
-		ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode, ValidationCodeHash,
-		ValidatorId, ValidatorIndex, ValidatorSignature,
+		vstaging::ExecutorParams, CandidateCommitments, CandidateEvent, CandidateHash,
+		CommittedCandidateReceipt, CoreState, DisputeState, GroupRotationInfo, Hash as RelayHash,
+		Header as RelayHeader, InboundHrmpMessage, OccupiedCoreAssumption, OldV1SessionInfo,
+		PvfCheckStatement, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode,
+		ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
 	},
 	InboundDownwardMessage, ParaId, PersistedValidationData,
 };
@@ -388,6 +388,20 @@ impl RelayChainRpcClient {
 			.await
 	}
 
+	/// Get the executor parameters for the given session, if stored
+	pub async fn parachain_host_session_executor_params(
+		&self,
+		at: RelayHash,
+		session_index: SessionIndex,
+	) -> Result<Option<ExecutorParams>, RelayChainError> {
+		self.call_remote_runtime_function(
+			"ParachainHost_session_executor_params",
+			at,
+			Some(session_index),
+		)
+		.await
+	}
+
 	/// Get header at specified hash
 	pub async fn chain_get_header(
 		&self,