Pallet session wrapper draft

Author: Klapeyron

demo/node/src/staging.rs

@@ -130,18 +130,22 @@ pub fn staging_genesis(
 		},
 		transaction_payment: Default::default(),
 		session: SessionConfig {
-			initial_validators: initial_authorities
+			keys: initial_authorities
 				.iter()
 				.map(|authority_keys| {
-					(authority_keys.cross_chain.clone().into(), authority_keys.session.clone())
+					(
+						authority_keys.cross_chain.clone().into(),
+						authority_keys.cross_chain.clone().into(),
+						authority_keys.session.clone(),
+					)
 				})
 				.collect(),
+			non_authority_keys: Default::default(),
 		},
 		sidechain: SidechainConfig {
 			genesis_utxo: sp_sidechain::read_genesis_utxo_from_env_with_defaults()?,
 			..Default::default()
 		},
-		pallet_session: Default::default(),
 		session_committee_management: SessionCommitteeManagementConfig {
 			initial_authorities: initial_authorities
 				.into_iter()

demo/node/src/template_chain_spec.rs

@@ -27,13 +27,13 @@ pub fn chain_spec() -> Result<ChainSpec, envy::Error> {
 		transaction_payment: Default::default(),
 		session: SessionConfig {
 			// Initial validators are meant to be updated in the chain spec file, so it is empty here.
-			initial_validators: vec![],
+			keys: vec![],
+			non_authority_keys: Default::default(),
 		},
 		sidechain: SidechainConfig {
 			genesis_utxo: sp_sidechain::read_genesis_utxo_from_env_with_defaults()?,
 			..Default::default()
 		},
-		pallet_session: Default::default(),
 		session_committee_management: SessionCommitteeManagementConfig {
 			// Same as SessionConfig
 			initial_authorities: vec![],

demo/node/src/testnet.rs

@@ -181,19 +181,23 @@ pub fn testnet_genesis(
 		},
 		transaction_payment: Default::default(),
 		session: SessionConfig {
-			initial_validators: initial_authorities
+			keys: initial_authorities
 				.iter()
 				.map(|authority_keys| {
-					(authority_keys.cross_chain.clone().into(), authority_keys.session.clone())
+					(
+						authority_keys.cross_chain.clone().into(),
+						authority_keys.cross_chain.clone().into(),
+						authority_keys.session.clone(),
+					)
 				})
 				.collect(),
+			non_authority_keys: Default::default(),
 		},
 		sidechain: SidechainConfig {
 			genesis_utxo: sp_sidechain::read_genesis_utxo_from_env_with_defaults()?,
 			slots_per_epoch: SlotsPerEpoch::read_from_env()?,
 			..Default::default()
 		},
-		pallet_session: Default::default(),
 		session_committee_management: SessionCommitteeManagementConfig {
 			initial_authorities: initial_authorities
 				.into_iter()

demo/runtime/Cargo.toml

@@ -32,7 +32,7 @@ pallet-grandpa = { workspace = true }
 pallet-partner-chains-session = { workspace = true, features = [
 	"pallet-session-compat",
 ] }
-pallet-session = { workspace = true }
+pallet-session = { workspace = true, features = ["historical"] }
 pallet-sudo = { workspace = true }
 frame-system = { workspace = true }
 frame-try-runtime = { workspace = true, optional = true }

demo/runtime/src/genesis_config_presets.rs

@@ -58,7 +58,6 @@ fn testnet_genesis(
 		transaction_payment: Default::default(),
 		sidechain: Default::default(),
 		session_committee_management: Default::default(),
-		pallet_session: Default::default(),
 		session: Default::default(),
 		native_token_management: Default::default(),
 		governed_map: GovernedMapConfig {

demo/runtime/src/lib.rs

@@ -46,6 +46,7 @@ use sp_core::ByteArray;
 use sp_core::{OpaqueMetadata, crypto::KeyTypeId};
 use sp_governed_map::MainChainScriptsV1;
 use sp_inherents::InherentIdentifier;
+use sp_runtime::traits::ConvertInto;
 use sp_runtime::{
 	ApplyExtrinsicResult, MultiSignature, Perbill, generic, impl_opaque_keys,
 	traits::{
@@ -309,7 +310,24 @@ impl pallet_aura::Config for Runtime {
 	type SlotDuration = ConstU64<SLOT_DURATION>;
 }
 
-pallet_partner_chains_session::impl_pallet_session_config!(Runtime);
+impl pallet_session::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type ValidatorId = AccountId;
+	type ValidatorIdOf = ConvertInto;
+	type ShouldEndSession = ValidatorManagementSessionManager<Runtime>;
+	type NextSessionRotation = ();
+	type SessionManager = ValidatorManagementSessionManager<Runtime>;
+	type SessionHandler = <SessionKeys as OpaqueKeys>::KeyTypeIdProviders;
+	type Keys = SessionKeys;
+	type DisablingStrategy = pallet_session::disabling::UpToLimitWithReEnablingDisablingStrategy;
+
+	type WeightInfo = pallet_session::weights::SubstrateWeight<Runtime>;
+}
+
+// impl pallet_session::historical::Config for Runtime {
+// 	type FullIdentification = ();
+// 	type FullIdentificationOf = ();
+// }
 
 impl pallet_grandpa::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
@@ -373,15 +391,6 @@ impl pallet_sudo::Config for Runtime {
 	type WeightInfo = pallet_sudo::weights::SubstrateWeight<Runtime>;
 }
 
-impl pallet_partner_chains_session::Config for Runtime {
-	type ValidatorId = <Self as frame_system::Config>::AccountId;
-	type ShouldEndSession = ValidatorManagementSessionManager<Runtime>;
-	type NextSessionRotation = ();
-	type SessionManager = ValidatorManagementSessionManager<Runtime>;
-	type SessionHandler = <opaque::SessionKeys as OpaqueKeys>::KeyTypeIdProviders;
-	type Keys = opaque::SessionKeys;
-}
-
 parameter_types! {
 	pub const MaxValidators: u32 = 1024;
 }
@@ -693,13 +702,8 @@ construct_runtime!(
 		BlockProducerMetadata: pallet_block_producer_metadata,
 		BlockProductionLog: pallet_block_production_log,
 		BlockParticipation: pallet_block_participation,
-		// pallet_grandpa reads pallet_session::pallet::CurrentIndex storage.
-		// Only stub implementation of pallet_session should be wired.
-		// Partner Chains session_manager ValidatorManagementSessionManager writes to pallet_session::pallet::CurrentIndex.
-		// ValidatorManagementSessionManager is wired in by pallet_partner_chains_session.
-		PalletSession: pallet_session,
-		// The order matters!! pallet_partner_chains_session needs to come last for correct initialization order
-		Session: pallet_partner_chains_session,
+		Session: pallet_session,
+		// Historical: pallet_session::historical,
 		NativeTokenManagement: pallet_native_token_management,
 		GovernedMap: pallet_governed_map,
 		TestHelperPallet: crate::test_helper_pallet,
@@ -895,7 +899,6 @@ impl_runtime_apis! {
 		}
 	}
 
-
 	impl frame_system_rpc_runtime_api::AccountNonceApi<Block, AccountId, Nonce> for Runtime {
 		fn account_nonce(account: AccountId) -> Nonce {
 			System::account_nonce(account)

toolkit/committee-selection/pallet/src/session_manager.rs

@@ -98,6 +98,47 @@ impl<T: crate::Config + pallet_session::Config>
 	}
 }
 
+impl<T: crate::Config + pallet_session::Config> pallet_session::SessionManager<T::AccountId>
+	for ValidatorManagementSessionManager<T>
+{
+	fn new_session_genesis(_new_index: SessionIndex) -> Option<Vec<T::AccountId>> {
+		Some(
+			crate::Pallet::<T>::current_committee_storage()
+				.committee
+				.into_iter()
+				.map(|member| member.authority_id().into())
+				.collect::<Vec<_>>(),
+		)
+	}
+
+	// Instead of Some((*).expect) we could just use (*). However, we rather panic in presence of
+	// important programming errors.
+	fn new_session(new_index: SessionIndex) -> Option<Vec<T::AccountId>> {
+		info!("New session {new_index}");
+		pallet_session::pallet::CurrentIndex::<T>::put(new_index);
+		Some(
+			crate::Pallet::<T>::rotate_committee_to_next_epoch()
+				.expect(
+					"Session should never end without current epoch validators defined. \
+				Check ShouldEndSession implementation or if it is used before starting new session",
+				)
+				.into_iter()
+				.map(|member| member.authority_id().into())
+				.collect(),
+		)
+	}
+
+	fn end_session(end_index: SessionIndex) {
+		info!("End session {end_index}");
+	}
+
+	// Session is expected to be at least 1 block behind sidechain epoch.
+	fn start_session(start_index: SessionIndex) {
+		let epoch_number = T::current_epoch_number();
+		info!("Start session {start_index}, epoch {epoch_number}");
+	}
+}
+
 /// This implementation tries to end each session in the first block of each sidechain epoch in which
 /// the committee for the epoch is defined.
 impl<T, ScEpochNumber> pallet_partner_chains_session::ShouldEndSession<BlockNumberFor<T>>
@@ -114,6 +155,22 @@ where
 	}
 }
 
+/// This implementation tries to end each session in the first block of each sidechain epoch in which
+/// the committee for the epoch is defined.
+impl<T, ScEpochNumber> pallet_session::ShouldEndSession<BlockNumberFor<T>>
+	for ValidatorManagementSessionManager<T>
+where
+	T: crate::Config<ScEpochNumber = ScEpochNumber>,
+	ScEpochNumber: Clone + PartialOrd,
+{
+	fn should_end_session(_n: BlockNumberFor<T>) -> bool {
+		let current_epoch_number = T::current_epoch_number();
+
+		current_epoch_number > crate::Pallet::<T>::current_committee_storage().epoch
+			&& crate::Pallet::<T>::next_committee().is_some()
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use crate::mock::mock_pallet::CurrentEpoch;