Refactor away from opaque hashes (#5226)

* System.BlockHash

* Fix hash

* Introduce K/V iteration in all _concat maps

Also move across:
- System.Account (blake2_128_concat)
- Balances.Locks (twox_64_concat)
- ElectionsPhragmen.VotesOf (twox_64_concat)
- ElectionsPhragmen.StakeOf (twox_64_concat)
- Identity.IdentityOf (twox_64_concat)
- Identity.SubsOf (twox_64_concat)
- Society.Payouts (twox_64_concat)
- Session.NextKeys (twox_64_concat)
- Identity.SuperOf (blake2_128_concat)
- Session.KeyOwner (blake2_128_concat)
- Society.SuspendedCandidates (twox_64_concat)
- Society.SuspendedMembers (twox_64_concat)
- Society.Vouching (twox_64_concat)
- Society.Strikes (twox_64_concat)
- System.EventTopics
- Balances.Account

* Build fixes

* Ensure migration happens in correct order

* Staking.*

* Vesting.* Offences.*

* Democracy.*

* Babe.* Collective.*

* Grandpa.*

* Assets.* Benchmark.* Contracts.* Elections.* Asset.* Nicks.*

Also introduce real account list

* ImOnline.*

* Treasury.*

* Recovery.*

* Final bits.

* Docs

* Fix one test

* Fix test

* All passing except the UI tests

* Remove linked_map part 1

* Remove linked_map

* Some iterator utils for double maps.

* Remove old migrations

* Introduce tombstone for LinkedMap type

* Migration for genesis hash

* Fix build

* Fix hash

* Rename Map is_linked -> unused, keeping backwards compat (#5256)

* Update frame/balances/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update frame/elections/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Remove old migration code.

* Update frame/system/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update bin/node/runtime/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Fix hash

* fix session migration

* Fix watning

Co-authored-by: Jaco Greeff <jacogr@gmail.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

substrate/frame/im-online/src/lib.rs

@@ -95,6 +95,7 @@ use frame_support::{
 };
 use frame_system::{self as system, ensure_none};
 use frame_system::offchain::SubmitUnsignedTransaction;
+use frame_support::traits::MigrateAccount;
 
 pub mod sr25519 {
 	mod app_sr25519 {
@@ -274,16 +275,17 @@ decl_storage! {
 		/// The current set of keys that may issue a heartbeat.
 		Keys get(fn keys): Vec<T::AuthorityId>;
 
-		/// For each session index, we keep a mapping of `AuthIndex`
-		/// to `offchain::OpaqueNetworkState`.
+		/// For each session index, we keep a mapping of `AuthIndex` to
+		/// `offchain::OpaqueNetworkState`.
 		ReceivedHeartbeats get(fn received_heartbeats):
-			double_map hasher(blake2_256) SessionIndex, hasher(blake2_256) AuthIndex
+			double_map hasher(twox_64_concat) SessionIndex, hasher(twox_64_concat) AuthIndex
 			=> Option<Vec<u8>>;
 
 		/// For each session index, we keep a mapping of `T::ValidatorId` to the
 		/// number of blocks authored by the given authority.
 		AuthoredBlocks get(fn authored_blocks):
-			double_map hasher(blake2_256) SessionIndex, hasher(blake2_256) T::ValidatorId => u32;
+			double_map hasher(twox_64_concat) SessionIndex, hasher(twox_64_concat) T::ValidatorId
+			=> u32;
 	}
 	add_extra_genesis {
 		config(keys): Vec<T::AuthorityId>;
@@ -301,12 +303,38 @@ decl_error! {
 	}
 }
 
+mod migration {
+	use super::*;
+	use frame_support::Blake2_256;
+	pub fn migrate<T: Trait>() {
+		let current_index = <pallet_session::Module<T>>::current_index();
+		let key_count = Keys::<T>::get().len() as AuthIndex;
+		for i in 0..key_count {
+			ReceivedHeartbeats::migrate_keys::<Blake2_256, Blake2_256, _, _>(current_index, i);
+		}
+	}
+}
+
+impl<T: Trait> MigrateAccount<T::AccountId> for Module<T> {
+	fn migrate_account(a: &T::AccountId) {
+		use frame_support::Blake2_256;
+		let current_index = <pallet_session::Module<T>>::current_index();
+		if let Ok(v) = a.using_encoded(|mut d| T::ValidatorId::decode(&mut d)) {
+			AuthoredBlocks::<T>::migrate_keys::<Blake2_256, Blake2_256, _, _>(current_index, v);
+		}
+	}
+}
+
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
 		type Error = Error<T>;
 
 		fn deposit_event() = default;
 
+		fn on_runtime_upgrade() {
+			migration::migrate::<T>();
+		}
+
 		fn heartbeat(
 			origin,
 			heartbeat: Heartbeat<T::BlockNumber>,

substrate/frame/im-online/src/mock.rs

@@ -119,7 +119,7 @@ impl frame_system::Trait for Runtime {
 	type Version = ();
 	type ModuleToIndex = ();
 	type AccountData = ();
-	type OnNewAccount = ();
+	type MigrateAccount = (); type OnNewAccount = ();
 	type OnKilledAccount = ();
 }