HOTFIX: Generate thea auth change message before era ends. (#849)

## Describe your changes
Thea should generate the validator session change message at the
beginning of the last epoch of an era and get the changes to effect at
the end.

## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [x] I removed all Clippy and Formatting Warnings. 
- [ ] I added required Copyrights.

pallets/thea/src/lib.rs

@@ -38,7 +38,7 @@ use sp_runtime::{
 	Percent, RuntimeAppPublic, SaturatedConversion,
 };
 use sp_std::prelude::*;
-use thea_primitives::{types::Message, Network, GENESIS_AUTHORITY_SET_ID};
+use thea_primitives::{types::Message, Network, ValidatorSet, GENESIS_AUTHORITY_SET_ID};
 
 #[cfg(feature = "runtime-benchmarks")]
 mod benchmarking;
@@ -358,28 +358,37 @@ impl<T: Config> Pallet<T> {
 	}
 
 	fn change_authorities(
-		incoming: BoundedVec<T::TheaId, T::MaxAuthorities>,
-		queued: BoundedVec<T::TheaId, T::MaxAuthorities>,
+		incoming: BoundedVec<T::TheaId, T::MaxAuthorities>, // n+1th set
+		queued: BoundedVec<T::TheaId, T::MaxAuthorities>,   // n+ 2th set
 	) {
+		//	( outgoing) -> (validators/incoming) -> (queued)
+		// nth epoch -> n+1th epoch -> n+2nd epoch
 		let id = Self::validator_set_id();
-		let outgoing = <Authorities<T>>::get(id);
+		let outgoing = <Authorities<T>>::get(id); // nth set  ( active ,current )
 		let new_id = id + 1u64;
 
 		// We need to issue a new message if the validator set is changing,
 		// that is, the incoming set is has different session keys from outgoing set.
 		// This last message should be signed by the outgoing set
 		// Similar to how Grandpa's session change works.
-		if outgoing != incoming {
+		if incoming != queued {
+			// This should happen at the beginning of the last epoch
 			let active_networks = <ActiveNetworks<T>>::get();
-			for network in active_networks {
-				let message = Self::generate_payload(true, network, incoming.encode());
-				// Update nonce
-				<OutgoingNonce<T>>::insert(message.network, message.nonce);
-				<OutgoingMessages<T>>::insert(message.network, message.nonce, message);
+			if let Some(validator_set) = ValidatorSet::new(queued.clone(), new_id) {
+				let payload = validator_set.encode();
+				for network in active_networks {
+					let message = Self::generate_payload(true, network, payload.clone());
+					// Update nonce
+					<OutgoingNonce<T>>::insert(message.network, message.nonce);
+					<OutgoingMessages<T>>::insert(message.network, message.nonce, message);
+				}
 			}
+			<NextAuthorities<T>>::put(queued);
+		}
+		if incoming != outgoing {
+			// This will happen when new era starts, or end of the last epoch
 			<Authorities<T>>::insert(new_id, incoming);
 			<ValidatorSetId<T>>::put(new_id);
-			<NextAuthorities<T>>::put(queued);
 		}
 	}
 

pallets/thea/src/tests.rs

@@ -65,32 +65,55 @@ use frame_support::traits::OneSessionHandler;
 #[test]
 fn test_session_change() {
 	new_test_ext().execute_with(|| {
-		let mut validators = Vec::with_capacity(200);
-		for i in 0..200 {
-			validators.push(
-				Pair::generate_with_phrase(Some(format!("{}//{}", WELL_KNOWN, i).as_str())).0,
-			);
+		let mut authorities: Vec<(&u64, <Test as Config>::TheaId)> = Vec::with_capacity(200);
+		for i in 0..200u64 {
+			authorities.push((
+				&1,
+				Pair::generate_with_phrase(Some(format!("{}//{}", WELL_KNOWN, i).as_str()))
+					.0
+					.public()
+					.into(),
+			));
+		}
+
+		let mut queued: Vec<(&u64, <Test as Config>::TheaId)> = Vec::with_capacity(200);
+		for i in 0..200u64 {
+			queued.push((
+				&1,
+				Pair::generate_with_phrase(Some(format!("{}//{}", WELL_KNOWN, i).as_str()))
+					.0
+					.public()
+					.into(),
+			));
 		}
 
-		let mut authorities = Vec::new();
-		validators
-			.clone()
-			.into_iter()
-			.for_each(|bls| authorities.push((&1, bls.public().into())));
 		let mut networks = BTreeSet::new();
 		networks.insert(1);
 		<ActiveNetworks<Test>>::put(networks);
 		assert!(Thea::validator_set_id() == 0);
 		assert!(Thea::outgoing_nonce(1) == 0);
-		let authorities_cloned: Vec<(&u64, <Test as Config>::TheaId)> = authorities.clone();
-		let auth_len = authorities_cloned.len();
-		Thea::on_new_session(false, authorities.into_iter(), authorities_cloned.into_iter());
+		let current_authorities: Vec<<Test as Config>::TheaId> =
+			authorities.iter().map(|(_, public)| public.clone()).collect();
+		<ValidatorSetId<Test>>::put(0);
+		<Authorities<Test>>::insert(0, BoundedVec::truncate_from(current_authorities));
+		// Simulating the on_new_session to last epoch of an era.
+		Thea::on_new_session(false, authorities.into_iter(), queued.clone().into_iter());
+		assert!(Thea::validator_set_id() == 0);
+		assert!(Thea::outgoing_nonce(1) == 1); // Thea validator session change message is generated here
+
+		let message = Thea::get_outgoing_messages(1, 1).unwrap();
+		assert_eq!(message.nonce, 1);
+		let validator_set: ValidatorSet<<Test as Config>::TheaId> =
+			ValidatorSet::decode(&mut &message.data[..]).unwrap();
+		let queued_validators: Vec<<Test as Config>::TheaId> =
+			queued.iter().map(|(_, public)| public.clone()).collect();
+		assert_eq!(validator_set.set_id, 1);
+		assert_eq!(validator_set.validators, queued_validators);
+
+		// Simulating the on_new_session to the first epoch of the next era.
+		Thea::on_new_session(false, queued.clone().into_iter(), queued.clone().into_iter());
 		assert!(Thea::validator_set_id() == 1);
 		assert!(Thea::outgoing_nonce(1) == 1);
-		let message = Thea::get_outgoing_messages(1, 1).unwrap();
-		let bounded_vec: BoundedVec<<Test as Config>::TheaId, <Test as Config>::MaxAuthorities> =
-			BoundedVec::decode(&mut &message.data[..]).unwrap();
-		assert_eq!(bounded_vec.to_vec().len(), auth_len);
 	})
 }
 

runtime/src/lib.rs

@@ -118,7 +118,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 289,
+	spec_version: 292,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 2,