Merge ValidatorSet into SessionInterface trait

Wrap a few too long lines

Add some docs

bin/node/runtime/src/lib.rs

@@ -421,8 +421,7 @@ impl pallet_session::Trait for Runtime {
 	type WeightInfo = weights::pallet_session::WeightInfo<Runtime>;
 }
 
-impl pallet_session::historical::Trait for Runtime {
-}
+impl pallet_session::historical::Trait for Runtime {}
 
 pallet_staking_reward_curve::build! {
 	const REWARD_CURVE: PiecewiseLinear<'static> = curve!(
@@ -757,23 +756,10 @@ impl<C> frame_system::offchain::SendTransactionTypes<C> for Runtime where
 	type OverarchingCall = Call;
 }
 
-impl pallet_im_online::ValidatorSet<<Self as pallet_session::ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId> for Runtime {
-	fn validators() -> Vec<<Self as pallet_session::ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId> {
-		Session::validators()
-	}
-}
-
-impl pallet_im_online::SessionInterface for Runtime {
-	fn current_index() -> sp_staking::SessionIndex {
-		Session::current_index()
-	}
-}
-
 impl pallet_im_online::Trait for Runtime {
 	type AuthorityId = ImOnlineId;
 	type Event = Event;
 	type SessionInterface = Self;
-	type ValidatorSet = Self;
 	type SessionDuration = SessionDuration;
 	type ReportUnresponsiveness = Offences;
 	type UnsignedPriority = ImOnlineUnsignedPriority;
@@ -786,7 +772,7 @@ parameter_types! {
 
 impl pallet_offences::Trait for Runtime {
 	type Event = Event;
-	type IdentificationTuple = pallet_session::IdentificationTuple<<Self as frame_system::Trait>::AccountId, Self>;
+	type IdentificationTuple = pallet_session::IdentificationTuple<AccountId, Self>;
 	type OnOffenceHandler = Staking;
 	type WeightSoftLimit = OffencesWeightSoftLimit;
 }

frame/authority-discovery/Cargo.toml

@@ -26,7 +26,6 @@ frame-system = { version = "2.0.0", default-features = false, path = "../system"
 [dev-dependencies]
 sp-core = { version = "2.0.0", path = "../../primitives/core" }
 sp-io = { version = "2.0.0", path = "../../primitives/io" }
-sp-session = { version = "2.0.0", path = "../../primitives/session" }
 sp-staking = { version = "2.0.0", default-features = false, path = "../../primitives/staking" }
 
 [features]

frame/im-online/Cargo.toml

@@ -21,7 +21,6 @@ sp-std = { version = "2.0.0", default-features = false, path = "../../primitives
 serde = { version = "1.0.101", optional = true }
 pallet-session = { version = "2.0.0", default-features = false, path = "../session" }
 sp-io = { version = "2.0.0", default-features = false, path = "../../primitives/io" }
-sp-session = { version = "2.0.0", default-features = false, path = "../../primitives/session" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-staking = { version = "2.0.0", default-features = false, path = "../../primitives/staking" }
 frame-support = { version = "2.0.0", default-features = false, path = "../support" }
@@ -41,11 +40,11 @@ std = [
 	"serde",
 	"pallet-session/std",
 	"sp-io/std",
-	"sp-session/std",
 	"sp-runtime/std",
 	"sp-staking/std",
 	"frame-support/std",
 	"frame-system/std",
+	"pallet-session/std",
 	"pallet-session-common/std",
 ]
 runtime-benchmarks = ["frame-benchmarking"]

frame/im-online/src/lib.rs

@@ -231,17 +231,39 @@ pub trait WeightInfo {
 	fn validate_unsigned_and_then_heartbeat(k: u32, e: u32, ) -> Weight;
 }
 
-/// The set of validators that are considered to be running an authority node.
-pub trait ValidatorSet<ValidatorId> {
-	/// Returns all the validators ought to be online.
+/// Trait for retrieving the session info needed for online node inspection.
+///
+/// This trait is used for decouple the pallet-session dependency from im-online
+/// module so that the user of im-online & offences modules can pass any list of
+/// validators that are considered to be online in each session, particularly useful
+/// for the Substrate-based projects having their own staking implementation
+/// instead of using pallet-staking directly.
+pub trait SessionInterface<ValidatorId> {
+	/// Returns current session index.
+	fn current_index() -> SessionIndex;
+
+	/// Returns all the validators ought to be online in a session.
+	///
+	/// The returned validators are all expected to be running an authority node.
 	fn validators() -> Vec<ValidatorId>;
 }
 
-pub trait SessionInterface {
-	fn current_index() -> SessionIndex;
+impl<T: pallet_session::Trait>
+	SessionInterface<<Self as ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId> for T
+{
+	fn current_index() -> sp_staking::SessionIndex {
+		pallet_session::Module::<T>::current_index()
+	}
+	fn validators() -> Vec<<Self as ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId> {
+		pallet_session::Module::<T>::validators()
+	}
 }
 
-pub trait Trait: SendTransactionTypes<Call<Self>> + ValidatorIdentification<<Self as frame_system::Trait>::AccountId> + frame_system::Trait {
+pub trait Trait:
+	SendTransactionTypes<Call<Self>>
+	+ ValidatorIdentification<<Self as frame_system::Trait>::AccountId>
+	+ frame_system::Trait
+{
 	/// The identifier type for an authority.
 	type AuthorityId: Member + Parameter + RuntimeAppPublic + Default + Ord;
 
@@ -256,10 +278,11 @@ pub trait Trait: SendTransactionTypes<Call<Self>> + ValidatorIdentification<<Sel
 	/// there is a chance the authority will produce a block and they won't be necessary.
 	type SessionDuration: Get<Self::BlockNumber>;
 
-	type SessionInterface: SessionInterface;
-
-	/// A set of validators expected to be online.
-	type ValidatorSet: ValidatorSet<<Self as ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId>;
+	/// A type for retrieving the necessary session info.
+	///
+	/// This is currently used to get the session index and list of validators expected to be online.
+	type SessionInterface:
+		SessionInterface<<Self as ValidatorIdentification<<Self as frame_system::Trait>::AccountId>>::ValidatorId>;
 
 	/// A type that gives us the ability to submit unresponsiveness offence reports.
 	type ReportUnresponsiveness:
@@ -312,10 +335,11 @@ decl_storage! {
 			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 as Trait>::ValidatorId` to the
-		/// number of blocks authored by the given authority.
+		/// For each session index, we keep a mapping of `<T as ValidatorIdentification<T::AccountId>>::ValidatorId`
+		/// to the number of blocks authored by the given authority.
 		AuthoredBlocks get(fn authored_blocks):
-			double_map hasher(twox_64_concat) SessionIndex, hasher(twox_64_concat) <T as ValidatorIdentification<T::AccountId>>::ValidatorId
+			double_map hasher(twox_64_concat) SessionIndex,
+					   hasher(twox_64_concat) <T as ValidatorIdentification<T::AccountId>>::ValidatorId
 			=> u32;
 	}
 	add_extra_genesis {
@@ -416,7 +440,12 @@ type OffchainResult<T, A> = Result<A, OffchainErr<<T as frame_system::Trait>::Bl
 
 /// Keep track of number of authored blocks per authority, uncles are counted as
 /// well since they're a valid proof of being online.
-impl<T: Trait + pallet_authorship::Trait> pallet_authorship::EventHandler<<T as ValidatorIdentification<T::AccountId>>::ValidatorId, T::BlockNumber> for Module<T> {
+impl<T: Trait + pallet_authorship::Trait>
+	pallet_authorship::EventHandler<
+		<T as ValidatorIdentification<T::AccountId>>::ValidatorId,
+		T::BlockNumber,
+	> for Module<T>
+{
 	fn note_author(author: <T as ValidatorIdentification<T::AccountId>>::ValidatorId) {
 		Self::note_authorship(author);
 	}
@@ -432,7 +461,7 @@ impl<T: Trait> Module<T> {
 	/// authored at least one block, during the current session. Otherwise
 	/// `false`.
 	pub fn is_online(authority_index: AuthIndex) -> bool {
-		let current_validators = T::ValidatorSet::validators();
+		let current_validators = T::SessionInterface::validators();
 
 		if authority_index >= current_validators.len() as u32 {
 			return false;
@@ -443,7 +472,10 @@ impl<T: Trait> Module<T> {
 		Self::is_online_aux(authority_index, authority)
 	}
 
-	fn is_online_aux(authority_index: AuthIndex, authority: &<T as ValidatorIdentification<T::AccountId>>::ValidatorId) -> bool {
+	fn is_online_aux(
+		authority_index: AuthIndex,
+		authority: &<T as ValidatorIdentification<T::AccountId>>::ValidatorId,
+	) -> bool {
 		let current_session = T::SessionInterface::current_index();
 
 		<ReceivedHeartbeats>::contains_key(&current_session, &authority_index) ||
@@ -480,7 +512,7 @@ impl<T: Trait> Module<T> {
 		}
 
 		let session_index = T::SessionInterface::current_index();
-		let validators_len = T::ValidatorSet::validators().len() as u32;
+		let validators_len = T::SessionInterface::validators().len() as u32;
 
 		Ok(Self::local_authority_keys()
 			.map(move |(authority_index, key)|
@@ -660,7 +692,7 @@ impl<T: Trait> pallet_session::OneSessionHandler<T::AccountId> for Module<T> {
 	fn on_before_session_ending() {
 		let session_index = T::SessionInterface::current_index();
 		let keys = Keys::<T>::get();
-		let current_validators = T::ValidatorSet::validators();
+		let current_validators = T::SessionInterface::validators();
 
 		let offenders = current_validators.into_iter().enumerate()
 			.filter(|(index, id)|

frame/im-online/src/mock.rs

@@ -21,14 +21,13 @@
 
 use std::cell::RefCell;
 
-use crate::{Module, Trait, ValidatorSet};
+use crate::{Module, Trait};
 use sp_runtime::Perbill;
 use sp_staking::{SessionIndex, offence::{ReportOffence, OffenceError}};
 use sp_runtime::testing::{Header, UintAuthorityId, TestXt};
 use sp_runtime::traits::{IdentityLookup, BlakeTwo256, ConvertInto};
 use sp_core::H256;
 use frame_support::{impl_outer_origin, impl_outer_dispatch, parameter_types, weights::Weight};
-use pallet_session::ValidatorIdentification;
 
 impl_outer_origin!{
 	pub enum Origin for Runtime {}
@@ -182,23 +181,10 @@ parameter_types! {
 	pub const UnsignedPriority: u64 = 1 << 20;
 }
 
-impl ValidatorSet<<Self as ValidatorIdentification<u64>>::ValidatorId> for Runtime {
-	fn validators() -> Vec<<Self as ValidatorIdentification<u64>>::ValidatorId> {
-		Session::validators()
-	}
-}
-
-impl crate::SessionInterface for Runtime {
-	fn current_index() -> SessionIndex {
-		Session::current_index()
-	}
-}
-
 impl Trait for Runtime {
 	type AuthorityId = UintAuthorityId;
 	type Event = ();
 	type ReportUnresponsiveness = OffenceHandler;
-	type ValidatorSet = Self;
 	type SessionInterface = Self;
 	type SessionDuration = Period;
 	type UnsignedPriority = UnsignedPriority;

frame/offences/benchmarking/Cargo.toml

@@ -26,7 +26,6 @@ pallet-session = { version = "2.0.0", default-features = false, path = "../../se
 pallet-staking = { version = "2.0.0", default-features = false, features = ["runtime-benchmarks"], path = "../../staking" }
 sp-runtime = { version = "2.0.0", default-features = false, path = "../../../primitives/runtime" }
 sp-staking = { version = "2.0.0", default-features = false, path = "../../../primitives/staking" }
-sp-session = { version = "2.0.0", default-features = false, path = "../../../primitives/session" }
 sp-std = { version = "2.0.0", default-features = false, path = "../../../primitives/std" }
 
 [dev-dependencies]
@@ -51,7 +50,6 @@ std = [
 	"pallet-staking/std",
 	"sp-runtime/std",
 	"sp-staking/std",
-	"sp-session/std",
 	"sp-std/std",
 	"codec/std",
 ]

frame/offences/benchmarking/src/lib.rs

@@ -66,13 +66,17 @@ pub trait Trait:
 /// and the one required by offences.
 pub trait IdTupleConvert<T: HistoricalTrait + OffencesTrait> {
 	/// Convert identification tuple from `historical` trait to the one expected by `offences`.
-	fn convert(id: IdentificationTuple<<T as frame_system::Trait>::AccountId, T>) -> <T as OffencesTrait>::IdentificationTuple;
+	fn convert(
+		id: IdentificationTuple<<T as frame_system::Trait>::AccountId, T>,
+	) -> <T as OffencesTrait>::IdentificationTuple;
 }
 
 impl<T: HistoricalTrait + OffencesTrait> IdTupleConvert<T> for T where
 	<T as OffencesTrait>::IdentificationTuple: From<IdentificationTuple<<T as frame_system::Trait>::AccountId, T>>
 {
-	fn convert(id: IdentificationTuple<<T as frame_system::Trait>::AccountId, T>) -> <T as OffencesTrait>::IdentificationTuple {
+	fn convert(
+		id: IdentificationTuple<<T as frame_system::Trait>::AccountId, T>,
+	) -> <T as OffencesTrait>::IdentificationTuple {
 		id.into()
 	}
 }
@@ -163,12 +167,15 @@ fn make_offenders<T: Trait>(num_offenders: u32, num_nominators: u32) -> Result<
 
 	Staking::<T>::start_session(0);
 
+	let validator_id_of =
+		<T as ValidatorIdentification<<T as frame_system::Trait>::AccountId>>::ValidatorIdOf::convert;
+	let full_identification_of =
+		<T as ValidatorIdentification<<T as frame_system::Trait>::AccountId>>::FullIdentificationOf::convert;
+
 	let id_tuples = offenders.iter()
-		.map(|offender|
-			<T as ValidatorIdentification<<T as frame_system::Trait>::AccountId>>::ValidatorIdOf::convert(offender.controller.clone())
-				.expect("failed to get validator id from account id"))
-		.map(|validator_id|
-			<T as ValidatorIdentification<<T as frame_system::Trait>::AccountId>>::FullIdentificationOf::convert(validator_id.clone())
+		.map(|offender| validator_id_of(offender.controller.clone())
+			.expect("failed to get validator id from account id"))
+		.map(|validator_id| full_identification_of(validator_id.clone())
 			.map(|full_id| (validator_id, full_id))
 			.expect("failed to convert validator id to full identification"))
 		.collect::<Vec<IdentificationTuple<<T as frame_system::Trait>::AccountId, T>>>();

frame/offences/benchmarking/src/mock.rs

@@ -187,22 +187,9 @@ impl pallet_staking::Trait for Test {
 	type WeightInfo = ();
 }
 
-impl pallet_im_online::ValidatorSet<<Self as pallet_session::ValidatorIdentification<AccountId>>::ValidatorId> for Test {
-	fn validators() -> Vec<<Self as pallet_session::ValidatorIdentification<AccountId>>::ValidatorId> {
-		Session::validators()
-	}
-}
-
-impl pallet_im_online::SessionInterface for Test {
-	fn current_index() -> sp_staking::SessionIndex {
-		Session::current_index()
-	}
-}
-
 impl pallet_im_online::Trait for Test {
 	type AuthorityId = UintAuthorityId;
 	type Event = Event;
-	type ValidatorSet = Self;
 	type SessionInterface = Self;
 	type SessionDuration = Period;
 	type ReportUnresponsiveness = Offences;

frame/session/Cargo.toml

@@ -30,7 +30,6 @@ impl-trait-for-tuples = "0.1.3"
 
 [dev-dependencies]
 sp-application-crypto = { version = "2.0.0", path = "../../primitives/application-crypto" }
-sp-session = { version = "2.0.0", path = "../../primitives/session" }
 lazy_static = "1.4.0"
 
 [features]

frame/session/common/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "pallet-session-common"
+version = "2.0.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "FRAME sessions common pallet"
+readme = "README.md"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+sp-runtime = { version = "2.0.0", default-features = false, path = "../../../primitives/runtime" }
+frame-support = { version = "2.0.0", default-features = false, path = "../../support" }
+
+[features]
+default = ["std"]
+std = [
+	"sp-runtime/std",
+	"frame-support/std",
+]