New Pallet: Root offences

Cargo.toml

@@ -135,6 +135,7 @@ members = [
 	"frame/staking/reward-fn",
 	"frame/state-trie-migration",
 	"frame/sudo",
+	"frame/root-offences",
 	"frame/support",
 	"frame/support/procedural",
 	"frame/support/procedural/tools",

frame/nomination-pools/src/lib.rs

@@ -2523,7 +2523,7 @@ impl<T: Config> Pallet<T> {
 impl<T: Config> OnStakerSlash<T::AccountId, BalanceOf<T>> for Pallet<T> {
 	fn on_slash(
 		pool_account: &T::AccountId,
-		// Bonded balance is always read directly from staking, therefore we need not update
+		// Bonded balance is always read directly from staking, therefore we don't need to update
 		// anything here.
 		slashed_bonded: BalanceOf<T>,
 		slashed_unlocking: &BTreeMap<EraIndex, BalanceOf<T>>,

frame/root-offences/Cargo.toml

@@ -0,0 +1,51 @@
+[package]
+name = "pallet-root-offences"
+version = "1.0.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://substrate.io"
+repository = "https://github.com/paritytech/substrate/"
+description = "FRAME root offences pallet"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+
+pallet-session = { version = "4.0.0-dev", features = [ "historical" ], path = "../../frame/session", default-features = false }
+pallet-staking = { version = "4.0.0-dev", default-features = false, path = "../../frame/staking" }
+pallet-offences = { version = "4.0.0-dev", default-features = false, path = "../../frame/offences" }
+
+frame-support = { version = "4.0.0-dev", default-features = false, path = "../support" }
+frame-system = { version = "4.0.0-dev", default-features = false, path = "../system" }
+sp-runtime = { version = "6.0.0", path = "../../primitives/runtime" }
+sp-staking = { version = "4.0.0-dev", default-features = false, path = "../../primitives/staking" }
+
+[dev-dependencies]
+pallet-balances = { version = "4.0.0-dev", path = "../balances" }
+pallet-timestamp = { version = "4.0.0-dev", path = "../timestamp" }
+pallet-staking-reward-curve = { version = "4.0.0-dev", path = "../staking/reward-curve" }
+
+sp-core = { version = "6.0.0", path = "../../primitives/core" }
+sp-io = { version = "6.0.0", default-features = false, path = "../../primitives/io" }
+sp-std = { version = "4.0.0", default-features = false, path = "../../primitives/std" }
+
+frame-election-provider-support = { version = "4.0.0-dev", path = "../election-provider-support" }
+
+[features]
+runtime-benchmarks = []
+try-runtime = ["frame-support/try-runtime"]
+default = ["std"]
+std = [
+	"codec/std",
+	"frame-support/std",
+    "frame-system/std",
+	"pallet-session/std",
+	"pallet-staking/std",
+	"pallet-offences/std",
+	"scale-info/std",
+	"sp-runtime/std",
+]

frame/root-offences/README.md

@@ -0,0 +1,5 @@
+# Sudo Offences Pallet
+
+Pallet that allows the root to create an offence.
+
+NOTE: This pallet should only be used for testing purposes.

frame/root-offences/src/lib.rs

@@ -0,0 +1,131 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2022 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.
+
+//! # Sudo Offences Pallet
+//! Pallet that allows the root to create an offence.
+//!
+//! NOTE: This pallet should be used for testing purposes.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(test)]
+mod mock;
+#[cfg(test)]
+mod tests;
+
+use pallet_session::historical::IdentificationTuple;
+use pallet_staking::{BalanceOf, Exposure, ExposureOf, Pallet as Staking};
+use sp_runtime::Perbill;
+use sp_staking::offence::{DisableStrategy, OnOffenceHandler};
+
+pub use pallet::*;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+
+	#[pallet::config]
+	pub trait Config:
+		frame_system::Config
+		+ pallet_staking::Config
+		+ pallet_session::Config<ValidatorId = <Self as frame_system::Config>::AccountId>
+		+ pallet_session::historical::Config<
+			FullIdentification = Exposure<
+				<Self as frame_system::Config>::AccountId,
+				BalanceOf<Self>,
+			>,
+			FullIdentificationOf = ExposureOf<Self>,
+		>
+	{
+		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
+	}
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		/// An offence was created by root.
+		OffenceCreated { offenders: Vec<(T::AccountId, Perbill)> },
+	}
+
+	#[pallet::error]
+	pub enum Error<T> {
+		/// Failed to get the active era from the staking pallet.
+		FailedToGetActiveEra,
+	}
+
+	type OffenceDetails<T> = sp_staking::offence::OffenceDetails<
+		<T as frame_system::Config>::AccountId,
+		IdentificationTuple<T>,
+	>;
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		/// Allows the `root`, for example sudo to create an offence.
+		#[pallet::weight(T::DbWeight::get().reads(2))]
+		pub fn create_offence(
+			origin: OriginFor<T>,
+			offenders: Vec<(T::AccountId, Perbill)>,
+		) -> DispatchResult {
+			ensure_root(origin)?;
+
+			let slash_fraction =
+				offenders.clone().into_iter().map(|(_, fraction)| fraction).collect::<Vec<_>>();
+			let offence_details = Self::get_offence_details(offenders.clone())?;
+
+			Self::submit_offence(&offence_details, &slash_fraction);
+			Self::deposit_event(Event::OffenceCreated { offenders });
+			Ok(())
+		}
+	}
+
+	impl<T: Config> Pallet<T> {
+		/// Returns a vector of offenders that are going to be slashed.
+		fn get_offence_details(
+			offenders: Vec<(T::AccountId, Perbill)>,
+		) -> Result<Vec<OffenceDetails<T>>, DispatchError> {
+			let now = Staking::<T>::active_era()
+				.map(|e| e.index)
+				.ok_or(Error::<T>::FailedToGetActiveEra)?;
+
+			Ok(offenders
+				.clone()
+				.into_iter()
+				.map(|(o, _)| OffenceDetails::<T> {
+					offender: (o.clone(), Staking::<T>::eras_stakers(now, o)),
+					reporters: vec![],
+				})
+				.collect())
+		}
+
+		/// Submits the offence by calling the `on_offence` function.
+		fn submit_offence(offenders: &[OffenceDetails<T>], slash_fraction: &[Perbill]) {
+			let session_index = <pallet_session::Pallet<T> as frame_support::traits::ValidatorSet<T::AccountId>>::session_index();
+
+			<pallet_staking::Pallet<T> as OnOffenceHandler<
+				T::AccountId,
+				IdentificationTuple<T>,
+				Weight,
+			>>::on_offence(&offenders, &slash_fraction, session_index, DisableStrategy::WhenSlashed);
+		}
+	}
+}