Authority Discovery to FRAME v2 (#8620)

* migrate to new macro

* formatting

* Apply suggestions from code review

* Update frame/authority-discovery/src/lib.rs

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

substrate/frame/authority-discovery/src/lib.rs

@@ -15,45 +15,87 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Authority discovery module.
+//! # Authority discovery pallet.
 //!
-//! This module is used by the `client/authority-discovery` and by polkadot's parachain logic
+//! This pallet is used by the `client/authority-discovery` and by polkadot's parachain logic
 //! to retrieve the current and the next set of authorities.
 
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use sp_std::prelude::*;
-use frame_support::{decl_module, decl_storage, traits::OneSessionHandler};
+use frame_support::traits::OneSessionHandler;
+#[cfg(feature = "std")]
+use frame_support::traits::GenesisBuild;
 use sp_authority_discovery::AuthorityId;
 
-/// The module's config trait.
-pub trait Config: frame_system::Config + pallet_session::Config {}
+pub use pallet::*;
 
-decl_storage! {
-	trait Store for Module<T: Config> as AuthorityDiscovery {
-		/// Keys of the current authority set.
-		Keys get(fn keys): Vec<AuthorityId>;
-		/// Keys of the next authority set.
-		NextKeys get(fn next_keys): Vec<AuthorityId>;
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::*;
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	#[pallet::config]
+	/// The pallet's config trait.
+	pub trait Config: frame_system::Config + pallet_session::Config {}
+
+	#[pallet::storage]
+	#[pallet::getter(fn keys)]
+	/// Keys of the current authority set.
+	pub(super) type Keys<T: Config> = StorageValue<
+		_,
+		Vec<AuthorityId>,
+		ValueQuery,
+	>;
+	
+	#[pallet::storage]
+	#[pallet::getter(fn next_keys)]
+	/// Keys of the next authority set.
+	pub(super) type NextKeys<T: Config> = StorageValue<
+		_,
+		Vec<AuthorityId>,
+		ValueQuery,
+	>;
+
+	#[pallet::genesis_config]
+	pub struct GenesisConfig {
+		pub keys: Vec<AuthorityId>,
 	}
-	add_extra_genesis {
-		config(keys): Vec<AuthorityId>;
-		build(|config| Module::<T>::initialize_keys(&config.keys))
+
+	#[cfg(feature = "std")]
+	impl Default for GenesisConfig {
+		fn default() -> Self {
+			Self {
+				keys: Default::default(),
+			}
+		}
 	}
+	#[pallet::genesis_build]
+	impl<T: Config> GenesisBuild<T> for GenesisConfig {
+		fn build(&self) {
+			Pallet::<T>::initialize_keys(&self.keys)
+		}
+	}
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
 }
 
-decl_module! {
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-	}
-}
-
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	/// Retrieve authority identifiers of the current and next authority set
 	/// sorted and deduplicated.
 	pub fn authorities() -> Vec<AuthorityId> {
-		let mut keys = Keys::get();
-		let next = NextKeys::get();
+		let mut keys = Keys::<T>::get();
+		let next = NextKeys::<T>::get();
 
 		keys.extend(next);
 		keys.sort();
@@ -64,28 +106,28 @@ impl<T: Config> Module<T> {
 
 	/// Retrieve authority identifiers of the current authority set in the original order.
 	pub fn current_authorities() -> Vec<AuthorityId> {
-		Keys::get()
+		Keys::<T>::get()
 	}
 
 	/// Retrieve authority identifiers of the next authority set in the original order.
 	pub fn next_authorities() -> Vec<AuthorityId> {
-		NextKeys::get()
+		NextKeys::<T>::get()
 	}
 
 	fn initialize_keys(keys: &[AuthorityId]) {
 		if !keys.is_empty() {
-			assert!(Keys::get().is_empty(), "Keys are already initialized!");
-			Keys::put(keys);
-			NextKeys::put(keys);
+			assert!(Keys::<T>::get().is_empty(), "Keys are already initialized!");
+			Keys::<T>::put(keys);
+			NextKeys::<T>::put(keys);
 		}
 	}
 }
 
-impl<T: Config> sp_runtime::BoundToRuntimeAppPublic for Module<T> {
+impl<T: Config> sp_runtime::BoundToRuntimeAppPublic for Pallet<T> {
 	type Public = AuthorityId;
 }
 
-impl<T: Config> OneSessionHandler<T::AccountId> for Module<T> {
+impl<T: Config> OneSessionHandler<T::AccountId> for Pallet<T> {
 	type Key = AuthorityId;
 
 	fn on_genesis_session<'a, I: 'a>(authorities: I)
@@ -102,9 +144,9 @@ impl<T: Config> OneSessionHandler<T::AccountId> for Module<T> {
 		// Remember who the authorities are for the new and next session.
 		if changed {
 			let keys = validators.map(|x| x.1);
-			Keys::put(keys.collect::<Vec<_>>());
+			Keys::<T>::put(keys.collect::<Vec<_>>());
 			let next_keys = queued_validators.map(|x| x.1);
-			NextKeys::put(next_keys.collect::<Vec<_>>());
+			NextKeys::<T>::put(next_keys.collect::<Vec<_>>());
 		}
 	}
 
@@ -113,6 +155,17 @@ impl<T: Config> OneSessionHandler<T::AccountId> for Module<T> {
 	}
 }
 
+#[cfg(feature = "std")]
+impl GenesisConfig {
+	/// Direct implementation of `GenesisBuild::assimilate_storage`.
+	pub fn assimilate_storage<T: Config>(
+		&self,
+		storage: &mut sp_runtime::Storage
+	) -> Result<(), String> {
+		<Self as GenesisBuild<T>>::assimilate_storage(self, storage)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use crate as pallet_authority_discovery;
@@ -221,7 +274,7 @@ mod tests {
 
 	#[test]
 	fn authorities_returns_current_and_next_authority_set() {
-		// The whole authority discovery module ignores account ids, but we still need them for
+		// The whole authority discovery pallet ignores account ids, but we still need them for
 		// `pallet_session::OneSessionHandler::on_new_session`, thus its safe to use the same value
 		// everywhere.
 		let account_id = AuthorityPair::from_seed_slice(vec![10; 32].as_ref()).unwrap().public();