pallet-session: Migrate the historical part to the new pallet macro (#9878)

* Migrate session-historical to the new pallet macro

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* pallet-session: Migrate the historical part to the new pallet macro

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* Fix staking test runtime

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* Update frame/session/src/historical/mod.rs

* Update frame/session/src/historical/mod.rs

* update migration doc

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* use hardcoded prefix for migration v1

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* cargo +nightly-2021-11-08 fmt

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>

substrate/frame/session/benchmarking/src/lib.rs

@@ -22,6 +22,7 @@
 
 mod mock;
 
+use sp_runtime::traits::{One, StaticLookup};
 use sp_std::{prelude::*, vec};
 
 use frame_benchmarking::benchmarks;
@@ -30,12 +31,11 @@ use frame_support::{
 	traits::{KeyOwnerProofSystem, OnInitialize},
 };
 use frame_system::RawOrigin;
-use pallet_session::{historical::Module as Historical, Pallet as Session, *};
+use pallet_session::{historical::Pallet as Historical, Pallet as Session, *};
 use pallet_staking::{
 	benchmarking::create_validator_with_nominators, testing_utils::create_validators,
 	RewardDestination,
 };
-use sp_runtime::traits::{One, StaticLookup};
 
 const MAX_VALIDATORS: u32 = 1000;
 

substrate/frame/session/src/historical/mod.rs

@@ -26,62 +26,74 @@
 //! These roots and proofs of inclusion can be generated at any time during the current session.
 //! Afterwards, the proofs can be fed to a consensus module when reporting misbehavior.
 
-use super::{Pallet as SessionModule, SessionIndex};
+pub mod offchain;
+pub mod onchain;
+mod shared;
+
 use codec::{Decode, Encode};
-use frame_support::{
-	decl_module, decl_storage, print,
-	traits::{ValidatorSet, ValidatorSetWithIdentification},
-	Parameter,
-};
 use sp_runtime::{
 	traits::{Convert, OpaqueKeys},
 	KeyTypeId,
 };
 use sp_session::{MembershipProof, ValidatorCount};
+use sp_staking::SessionIndex;
 use sp_std::prelude::*;
 use sp_trie::{
 	trie_types::{TrieDB, TrieDBMut},
 	MemoryDB, Recorder, Trie, TrieMut, EMPTY_PREFIX,
 };
 
-pub mod offchain;
-pub mod onchain;
-mod shared;
+use frame_support::{
+	print,
+	traits::{KeyOwnerProofSystem, StorageVersion, ValidatorSet, ValidatorSetWithIdentification},
+	Parameter,
+};
 
-/// Config necessary for the historical module.
-pub trait Config: super::Config {
-	/// Full identification of the validator.
-	type FullIdentification: Parameter;
+use crate::{self as pallet_session, Pallet as Session};
 
-	/// A conversion from validator ID to full identification.
-	///
-	/// This should contain any references to economic actors associated with the
-	/// validator, since they may be outdated by the time this is queried from a
-	/// historical trie.
-	///
-	/// It must return the identification for the current session index.
-	type FullIdentificationOf: Convert<Self::ValidatorId, Option<Self::FullIdentification>>;
-}
+pub use pallet::*;
 
-decl_storage! {
-	trait Store for Module<T: Config> as Session {
-		/// Mapping from historical session indices to session-data root hash and validator count.
-		HistoricalSessions get(fn historical_root):
-			map hasher(twox_64_concat) SessionIndex => Option<(T::Hash, ValidatorCount)>;
-		/// The range of historical sessions we store. [first, last)
-		StoredRange: Option<(SessionIndex, SessionIndex)>;
-		/// Deprecated.
-		CachedObsolete:
-			map hasher(twox_64_concat) SessionIndex
-			=> Option<Vec<(T::ValidatorId, T::FullIdentification)>>;
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+
+	/// The current storage version.
+	const STORAGE_VERSION: StorageVersion = StorageVersion::new(1);
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	#[pallet::storage_version(STORAGE_VERSION)]
+	pub struct Pallet<T>(_);
+
+	/// Config necessary for the historical pallet.
+	#[pallet::config]
+	pub trait Config: pallet_session::Config + frame_system::Config {
+		/// Full identification of the validator.
+		type FullIdentification: Parameter;
+
+		/// A conversion from validator ID to full identification.
+		///
+		/// This should contain any references to economic actors associated with the
+		/// validator, since they may be outdated by the time this is queried from a
+		/// historical trie.
+		///
+		/// It must return the identification for the current session index.
+		type FullIdentificationOf: Convert<Self::ValidatorId, Option<Self::FullIdentification>>;
 	}
+
+	/// Mapping from historical session indices to session-data root hash and validator count.
+	#[pallet::storage]
+	#[pallet::getter(fn historical_root)]
+	pub type HistoricalSessions<T: Config> =
+		StorageMap<_, Twox64Concat, SessionIndex, (T::Hash, ValidatorCount), OptionQuery>;
+
+	/// The range of historical sessions we store. [first, last)
+	#[pallet::storage]
+	pub type StoredRange<T> = StorageValue<_, (SessionIndex, SessionIndex), OptionQuery>;
 }
 
-decl_module! {
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {}
-}
-
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	/// Prune historical stored session roots up to (but not including)
 	/// `up_to`.
 	pub fn prune_up_to(up_to: SessionIndex) {
@@ -109,7 +121,7 @@ impl<T: Config> Module<T> {
 	}
 }
 
-impl<T: Config> ValidatorSet<T::AccountId> for Module<T> {
+impl<T: Config> ValidatorSet<T::AccountId> for Pallet<T> {
 	type ValidatorId = T::ValidatorId;
 	type ValidatorIdOf = T::ValidatorIdOf;
 
@@ -122,7 +134,7 @@ impl<T: Config> ValidatorSet<T::AccountId> for Module<T> {
 	}
 }
 
-impl<T: Config> ValidatorSetWithIdentification<T::AccountId> for Module<T> {
+impl<T: Config> ValidatorSetWithIdentification<T::AccountId> for Pallet<T> {
 	type Identification = T::FullIdentification;
 	type IdentificationOf = T::FullIdentificationOf;
 }
@@ -130,7 +142,7 @@ impl<T: Config> ValidatorSetWithIdentification<T::AccountId> for Module<T> {
 /// Specialization of the crate-level `SessionManager` which returns the set of full identification
 /// when creating a new session.
 pub trait SessionManager<ValidatorId, FullIdentification>:
-	crate::SessionManager<ValidatorId>
+	pallet_session::SessionManager<ValidatorId>
 {
 	/// If there was a validator set change, its returns the set of new validators along with their
 	/// full identifications.
@@ -150,7 +162,7 @@ pub struct NoteHistoricalRoot<T, I>(sp_std::marker::PhantomData<(T, I)>);
 
 impl<T: Config, I: SessionManager<T::ValidatorId, T::FullIdentification>> NoteHistoricalRoot<T, I> {
 	fn do_new_session(new_index: SessionIndex, is_genesis: bool) -> Option<Vec<T::ValidatorId>> {
-		StoredRange::mutate(|range| {
+		<StoredRange<T>>::mutate(|range| {
 			range.get_or_insert_with(|| (new_index, new_index)).1 = new_index + 1;
 		});
 
@@ -183,7 +195,7 @@ impl<T: Config, I: SessionManager<T::ValidatorId, T::FullIdentification>> NoteHi
 	}
 }
 
-impl<T: Config, I> crate::SessionManager<T::ValidatorId> for NoteHistoricalRoot<T, I>
+impl<T: Config, I> pallet_session::SessionManager<T::ValidatorId> for NoteHistoricalRoot<T, I>
 where
 	I: SessionManager<T::ValidatorId, T::FullIdentification>,
 {
@@ -207,7 +219,7 @@ where
 
 /// A tuple of the validator's ID and their full identification.
 pub type IdentificationTuple<T> =
-	(<T as crate::Config>::ValidatorId, <T as Config>::FullIdentification);
+	(<T as pallet_session::Config>::ValidatorId, <T as Config>::FullIdentification);
 
 /// A trie instance for checking and generating proofs.
 pub struct ProvingTrie<T: Config> {
@@ -227,7 +239,7 @@ impl<T: Config> ProvingTrie<T> {
 			let mut trie = TrieDBMut::new(&mut db, &mut root);
 			for (i, (validator, full_id)) in validators.into_iter().enumerate() {
 				let i = i as u32;
-				let keys = match <SessionModule<T>>::load_keys(&validator) {
+				let keys = match <Session<T>>::load_keys(&validator) {
 					None => continue,
 					Some(k) => k,
 				};
@@ -304,15 +316,13 @@ impl<T: Config> ProvingTrie<T> {
 	}
 }
 
-impl<T: Config, D: AsRef<[u8]>> frame_support::traits::KeyOwnerProofSystem<(KeyTypeId, D)>
-	for Module<T>
-{
+impl<T: Config, D: AsRef<[u8]>> KeyOwnerProofSystem<(KeyTypeId, D)> for Pallet<T> {
 	type Proof = MembershipProof;
 	type IdentificationTuple = IdentificationTuple<T>;
 
 	fn prove(key: (KeyTypeId, D)) -> Option<Self::Proof> {
-		let session = <SessionModule<T>>::current_index();
-		let validators = <SessionModule<T>>::validators()
+		let session = <Session<T>>::current_index();
+		let validators = <Session<T>>::validators()
 			.into_iter()
 			.filter_map(|validator| {
 				T::FullIdentificationOf::convert(validator.clone())
@@ -335,10 +345,10 @@ impl<T: Config, D: AsRef<[u8]>> frame_support::traits::KeyOwnerProofSystem<(KeyT
 	fn check_proof(key: (KeyTypeId, D), proof: Self::Proof) -> Option<IdentificationTuple<T>> {
 		let (id, data) = key;
 
-		if proof.session == <SessionModule<T>>::current_index() {
-			<SessionModule<T>>::key_owner(id, data.as_ref()).and_then(|owner| {
+		if proof.session == <Session<T>>::current_index() {
+			<Session<T>>::key_owner(id, data.as_ref()).and_then(|owner| {
 				T::FullIdentificationOf::convert(owner.clone()).and_then(move |id| {
-					let count = <SessionModule<T>>::validators().len() as ValidatorCount;
+					let count = <Session<T>>::validators().len() as ValidatorCount;
 
 					if count != proof.validator_count {
 						return None
@@ -374,7 +384,7 @@ pub(crate) mod tests {
 		BasicExternalities,
 	};
 
-	type Historical = Module<Test>;
+	type Historical = Pallet<Test>;
 
 	pub(crate) fn new_test_ext() -> sp_io::TestExternalities {
 		let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
@@ -386,7 +396,9 @@ pub(crate) mod tests {
 				frame_system::Pallet::<Test>::inc_providers(k);
 			}
 		});
-		crate::GenesisConfig::<Test> { keys }.assimilate_storage(&mut t).unwrap();
+		pallet_session::GenesisConfig::<Test> { keys }
+			.assimilate_storage(&mut t)
+			.unwrap();
 		sp_io::TestExternalities::new(t)
 	}
 
@@ -436,27 +448,27 @@ pub(crate) mod tests {
 				Session::on_initialize(i);
 			}
 
-			assert_eq!(StoredRange::get(), Some((0, 100)));
+			assert_eq!(<StoredRange<Test>>::get(), Some((0, 100)));
 
 			for i in 0..100 {
 				assert!(Historical::historical_root(i).is_some())
 			}
 
 			Historical::prune_up_to(10);
-			assert_eq!(StoredRange::get(), Some((10, 100)));
+			assert_eq!(<StoredRange<Test>>::get(), Some((10, 100)));
 
 			Historical::prune_up_to(9);
-			assert_eq!(StoredRange::get(), Some((10, 100)));
+			assert_eq!(<StoredRange<Test>>::get(), Some((10, 100)));
 
 			for i in 10..100 {
 				assert!(Historical::historical_root(i).is_some())
 			}
 
 			Historical::prune_up_to(99);
-			assert_eq!(StoredRange::get(), Some((99, 100)));
+			assert_eq!(<StoredRange<Test>>::get(), Some((99, 100)));
 
 			Historical::prune_up_to(100);
-			assert_eq!(StoredRange::get(), None);
+			assert_eq!(<StoredRange<Test>>::get(), None);
 
 			for i in 99..199u64 {
 				set_next_validators(vec![i]);
@@ -466,14 +478,14 @@ pub(crate) mod tests {
 				Session::on_initialize(i);
 			}
 
-			assert_eq!(StoredRange::get(), Some((100, 200)));
+			assert_eq!(<StoredRange<Test>>::get(), Some((100, 200)));
 
 			for i in 100..200 {
 				assert!(Historical::historical_root(i).is_some())
 			}
 
 			Historical::prune_up_to(9999);
-			assert_eq!(StoredRange::get(), None);
+			assert_eq!(<StoredRange<Test>>::get(), None);
 
 			for i in 100..200 {
 				assert!(Historical::historical_root(i).is_none())

substrate/frame/session/src/historical/offchain.rs

@@ -140,7 +140,7 @@ pub fn keep_newest<T: Config>(n_to_keep: usize) {
 mod tests {
 	use super::*;
 	use crate::{
-		historical::{onchain, Module},
+		historical::{onchain, Pallet},
 		mock::{force_new_session, set_next_validators, Session, System, Test, NEXT_VALIDATORS},
 	};
 
@@ -156,7 +156,7 @@ mod tests {
 		BasicExternalities,
 	};
 
-	type Historical = Module<Test>;
+	type Historical = Pallet<Test>;
 
 	pub fn new_test_ext() -> sp_io::TestExternalities {
 		let mut t = frame_system::GenesisConfig::default()

substrate/frame/session/src/lib.rs

@@ -108,6 +108,7 @@
 
 #[cfg(feature = "historical")]
 pub mod historical;
+pub mod migrations;
 #[cfg(test)]
 mod mock;
 #[cfg(test)]

substrate/frame/session/src/migrations/mod.rs

@@ -0,0 +1,24 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Version 1.
+///
+/// In version 0 session historical pallet uses `Session` for storage module prefix.
+/// In version 1 it uses its name as configured in `construct_runtime`.
+/// This migration moves session historical pallet storages from old prefix to new prefix.
+#[cfg(feature = "historical")]
+pub mod v1;

substrate/frame/session/src/migrations/v1.rs

@@ -0,0 +1,194 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use sp_io::hashing::twox_128;
+use sp_std::str;
+
+use frame_support::{
+	storage::{generator::StorageValue, StoragePrefixedMap},
+	traits::{
+		Get, GetStorageVersion, PalletInfoAccess, StorageVersion,
+		STORAGE_VERSION_STORAGE_KEY_POSTFIX,
+	},
+	weights::Weight,
+};
+
+use crate::historical as pallet_session_historical;
+
+const OLD_PREFIX: &str = "Session";
+
+/// Migrate the entire storage of this pallet to a new prefix.
+///
+/// This new prefix must be the same as the one set in construct_runtime.
+///
+/// The migration will look into the storage version in order not to trigger a migration on an up
+/// to date storage. Thus the on chain storage version must be less than 1 in order to trigger the
+/// migration.
+pub fn migrate<T: pallet_session_historical::Config, P: GetStorageVersion + PalletInfoAccess>(
+) -> Weight {
+	let new_pallet_name = <P as PalletInfoAccess>::name();
+
+	if new_pallet_name == OLD_PREFIX {
+		log::info!(
+			target: "runtime::session_historical",
+			"New pallet name is equal to the old prefix. No migration needs to be done.",
+		);
+		return 0
+	}
+
+	let on_chain_storage_version = <P as GetStorageVersion>::on_chain_storage_version();
+	log::info!(
+		target: "runtime::session_historical",
+		"Running migration to v1 for session_historical with storage version {:?}",
+		on_chain_storage_version,
+	);
+
+	if on_chain_storage_version < 1 {
+		let storage_prefix = pallet_session_historical::HistoricalSessions::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			OLD_PREFIX.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, OLD_PREFIX, new_pallet_name);
+
+		let storage_prefix = pallet_session_historical::StoredRange::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			OLD_PREFIX.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, OLD_PREFIX, new_pallet_name);
+
+		StorageVersion::new(1).put::<P>();
+		<T as frame_system::Config>::BlockWeights::get().max_block
+	} else {
+		log::warn!(
+			target: "runtime::session_historical",
+			"Attempted to apply migration to v1 but failed because storage version is {:?}",
+			on_chain_storage_version,
+		);
+		0
+	}
+}
+
+/// Some checks prior to migration. This can be linked to
+/// [`frame_support::traits::OnRuntimeUpgrade::pre_upgrade`] for further testing.
+///
+/// Panics if anything goes wrong.
+pub fn pre_migrate<
+	T: pallet_session_historical::Config,
+	P: GetStorageVersion + PalletInfoAccess,
+>() {
+	let new_pallet_name = <P as PalletInfoAccess>::name();
+
+	let storage_prefix_historical_sessions =
+		pallet_session_historical::HistoricalSessions::<T>::storage_prefix();
+	let storage_prefix_stored_range = pallet_session_historical::StoredRange::<T>::storage_prefix();
+
+	log_migration("pre-migration", storage_prefix_historical_sessions, OLD_PREFIX, new_pallet_name);
+	log_migration("pre-migration", storage_prefix_stored_range, OLD_PREFIX, new_pallet_name);
+
+	if new_pallet_name == OLD_PREFIX {
+		return
+	}
+
+	let new_pallet_prefix = twox_128(new_pallet_name.as_bytes());
+	let storage_version_key = twox_128(STORAGE_VERSION_STORAGE_KEY_POSTFIX);
+
+	let mut new_pallet_prefix_iter = frame_support::storage::KeyPrefixIterator::new(
+		new_pallet_prefix.to_vec(),
+		new_pallet_prefix.to_vec(),
+		|key| Ok(key.to_vec()),
+	);
+
+	// Ensure nothing except the storage_version_key is stored in the new prefix.
+	assert!(new_pallet_prefix_iter.all(|key| key == storage_version_key));
+
+	assert!(<P as GetStorageVersion>::on_chain_storage_version() < 1);
+}
+
+/// Some checks for after migration. This can be linked to
+/// [`frame_support::traits::OnRuntimeUpgrade::post_upgrade`] for further testing.
+///
+/// Panics if anything goes wrong.
+pub fn post_migrate<
+	T: pallet_session_historical::Config,
+	P: GetStorageVersion + PalletInfoAccess,
+>() {
+	let new_pallet_name = <P as PalletInfoAccess>::name();
+
+	let storage_prefix_historical_sessions =
+		pallet_session_historical::HistoricalSessions::<T>::storage_prefix();
+	let storage_prefix_stored_range = pallet_session_historical::StoredRange::<T>::storage_prefix();
+
+	log_migration(
+		"post-migration",
+		storage_prefix_historical_sessions,
+		OLD_PREFIX,
+		new_pallet_name,
+	);
+	log_migration("post-migration", storage_prefix_stored_range, OLD_PREFIX, new_pallet_name);
+
+	if new_pallet_name == OLD_PREFIX {
+		return
+	}
+
+	// Assert that no `HistoricalSessions` and `StoredRange` storages remains at the old prefix.
+	let old_pallet_prefix = twox_128(OLD_PREFIX.as_bytes());
+	let old_historical_sessions_key =
+		[&old_pallet_prefix, &twox_128(storage_prefix_historical_sessions)[..]].concat();
+	let old_historical_sessions_key_iter = frame_support::storage::KeyPrefixIterator::new(
+		old_historical_sessions_key.to_vec(),
+		old_historical_sessions_key.to_vec(),
+		|_| Ok(()),
+	);
+	assert_eq!(old_historical_sessions_key_iter.count(), 0);
+
+	let old_stored_range_key =
+		[&old_pallet_prefix, &twox_128(storage_prefix_stored_range)[..]].concat();
+	let old_stored_range_key_iter = frame_support::storage::KeyPrefixIterator::new(
+		old_stored_range_key.to_vec(),
+		old_stored_range_key.to_vec(),
+		|_| Ok(()),
+	);
+	assert_eq!(old_stored_range_key_iter.count(), 0);
+
+	// Assert that the `HistoricalSessions` and `StoredRange` storages (if they exist) have been
+	// moved to the new prefix.
+	// NOTE: storage_version_key is already in the new prefix.
+	let new_pallet_prefix = twox_128(new_pallet_name.as_bytes());
+	let new_pallet_prefix_iter = frame_support::storage::KeyPrefixIterator::new(
+		new_pallet_prefix.to_vec(),
+		new_pallet_prefix.to_vec(),
+		|_| Ok(()),
+	);
+	assert!(new_pallet_prefix_iter.count() >= 1);
+
+	assert_eq!(<P as GetStorageVersion>::on_chain_storage_version(), 1);
+}
+
+fn log_migration(stage: &str, storage_prefix: &[u8], old_pallet_name: &str, new_pallet_name: &str) {
+	log::info!(
+		target: "runtime::session_historical",
+		"{} prefix of storage '{}': '{}' ==> '{}'",
+		stage,
+		str::from_utf8(storage_prefix).unwrap_or("<Invalid UTF8>"),
+		old_pallet_name,
+		new_pallet_name,
+	);
+}

substrate/frame/session/src/tests.rs

@@ -453,3 +453,30 @@ fn upgrade_keys() {
 		}
 	})
 }
+
+#[cfg(feature = "historical")]
+#[test]
+fn test_migration_v1() {
+	use crate::{
+		historical::{HistoricalSessions, StoredRange},
+		mock::Historical,
+	};
+	use frame_support::traits::PalletInfoAccess;
+
+	new_test_ext().execute_with(|| {
+		assert!(<HistoricalSessions<Test>>::iter_values().count() > 0);
+		assert!(<StoredRange<Test>>::exists());
+
+		let old_pallet = "Session";
+		let new_pallet = <Historical as PalletInfoAccess>::name();
+		frame_support::storage::migration::move_pallet(
+			new_pallet.as_bytes(),
+			old_pallet.as_bytes(),
+		);
+		StorageVersion::new(0).put::<Historical>();
+
+		crate::migrations::v1::pre_migrate::<Test, Historical>();
+		crate::migrations::v1::migrate::<Test, Historical>();
+		crate::migrations::v1::post_migrate::<Test, Historical>();
+	});
+}

substrate/frame/staking/src/mock.rs

@@ -96,6 +96,7 @@ frame_support::construct_runtime!(
 		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
 		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>},
 		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		Historical: pallet_session::historical::{Pallet, Storage},
 		BagsList: pallet_bags_list::{Pallet, Call, Storage, Event<T>},
 	}
 );