companion for #substrate-8242

bin/node/runtime/pangolin/src/im_online.rs

@@ -5,14 +5,13 @@ use sp_runtime::transaction_validity::TransactionPriority;
 use crate::*;
 
 frame_support::parameter_types! {
-	pub const SessionDuration: BlockNumber = BLOCKS_PER_SESSION as _;
 	pub const ImOnlineUnsignedPriority: TransactionPriority = TransactionPriority::max_value();
 }
 impl Config for Runtime {
 	type AuthorityId = AuthorityId;
 	type Event = Event;
+	type NextSessionRotation = Babe;
 	type ValidatorSet = Historical;
-	type SessionDuration = SessionDuration;
 	type ReportUnresponsiveness = Offences;
 	type UnsignedPriority = ImOnlineUnsignedPriority;
 	type WeightInfo = SubstrateWeight<Runtime>;

frame/staking/src/lib.rs

@@ -1057,7 +1057,10 @@ decl_module! {
 				// either current session final based on the plan, or we're forcing.
 				(Self::is_current_session_final() || Self::will_era_be_forced())
 			{
-				if let Some(next_session_change) = T::NextNewSession::estimate_next_new_session(now) {
+				let (maybe_next_session_change, estimate_next_new_session_weight) =
+					T::NextNewSession::estimate_next_new_session(now);
+
+				if let Some(next_session_change) = maybe_next_session_change {
 					if let Some(remaining) = next_session_change.checked_sub(&now) {
 						if remaining <= T::ElectionLookahead::get() && !remaining.is_zero() {
 							// create snapshot.
@@ -1079,7 +1082,7 @@ decl_module! {
 				} else {
 					log!(warn, "Estimating next session change failed.");
 				}
-				add_weight(0, 0, T::NextNewSession::weight(now))
+				add_weight(0, 0, estimate_next_new_session_weight)
 			}
 
 			// For `era_election_status`, `is_current_session_final`, `will_era_be_forced`
@@ -3679,6 +3682,7 @@ impl<T: Config> sp_election_providers::ElectionDataProvider<T::AccountId, T::Blo
 		let session_length = T::NextNewSession::average_session_length();
 
 		let until_this_session_end = T::NextNewSession::estimate_next_new_session(now)
+			.0
 			.unwrap_or_default()
 			.saturating_sub(now);