Keep im-online events decodable after pallet removal (#235)

This is a follow-up to #178, which aims to keep the `im-online` pallet events decodable after the pallet itself is removed. As [discussed](#178 (comment)), the inability to decode events may result in missing a candidate in approval voting and a parachain finality stall. Although the circumstances of such an event are unlikely, it's better to safeguard them. The transient code introduced in this PR should be removed after the upgrade is enacted. - [x] Does not require a CHANGELOG entry
polkadot-fellows · Mar 15, 2024 · 64c9e16 · 64c9e16
1 parent 80aaf79
commit 64c9e16
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diff --git a/Cargo.lock b/Cargo.lock
diff --git a/relay/kusama/Cargo.toml b/relay/kusama/Cargo.toml
@@ -22,6 +22,7 @@ sp-api = { default-features = false , version = "27.0.0" }
 inherents = { package = "sp-inherents", default-features = false , version = "27.0.0" }
 offchain-primitives = { package = "sp-offchain", default-features = false , version = "27.0.0" }
 sp-std = { package = "sp-std", default-features = false , version = "14.0.0" }
+sp-application-crypto = { default-features = false , version = "31.0.0" }
 sp-arithmetic = { default-features = false , version = "24.0.0" }
 sp-genesis-builder = { default-features = false , version = "0.8.0" }
 sp-io = { default-features = false , version = "31.0.0" }
@@ -55,7 +56,6 @@ frame-executive = { default-features = false , version = "29.0.0" }
 pallet-grandpa = { default-features = false , version = "29.0.0" }
 pallet-nis = { default-features = false , version = "29.0.0" }
 pallet-identity = { default-features = false , version = "29.0.0" }
-pallet-im-online = { default-features = false , version = "28.0.0" }
 pallet-indices = { default-features = false , version = "29.0.0" }
 pallet-message-queue = { default-features = false , version = "32.0.0" }
 pallet-mmr = { default-features = false , version = "28.0.0" }
@@ -154,7 +154,6 @@ std = [
 	"pallet-fast-unstake/std",
 	"pallet-grandpa/std",
 	"pallet-identity/std",
-	"pallet-im-online/std",
 	"pallet-indices/std",
 	"pallet-message-queue/std",
 	"pallet-mmr/std",
@@ -192,6 +191,7 @@ std = [
 	"runtime-parachains/std",
 	"scale-info/std",
 	"sp-api/std",
+	"sp-application-crypto/std",
 	"sp-arithmetic/std",
 	"sp-core/std",
 	"sp-debug-derive/std",
@@ -228,7 +228,6 @@ runtime-benchmarks = [
 	"pallet-fast-unstake/runtime-benchmarks",
 	"pallet-grandpa/runtime-benchmarks",
 	"pallet-identity/runtime-benchmarks",
-	"pallet-im-online/runtime-benchmarks",
 	"pallet-indices/runtime-benchmarks",
 	"pallet-message-queue/runtime-benchmarks",
 	"pallet-mmr/runtime-benchmarks",
@@ -285,7 +284,6 @@ try-runtime = [
 	"pallet-fast-unstake/try-runtime",
 	"pallet-grandpa/try-runtime",
 	"pallet-identity/try-runtime",
-	"pallet-im-online/try-runtime",
 	"pallet-indices/try-runtime",
 	"pallet-message-queue/try-runtime",
 	"pallet-mmr/try-runtime",

diff --git a/relay/kusama/src/lib.rs b/relay/kusama/src/lib.rs
@@ -1574,6 +1574,59 @@ impl pallet_asset_rate::Config for Runtime {
 	type BenchmarkHelper = runtime_common::impls::benchmarks::AssetRateArguments;
 }
 
+// A mock pallet to keep `ImOnline` events decodable after pallet removal
+pub mod pallet_im_online {
+	use frame_support::pallet_prelude::*;
+	pub use pallet::*;
+
+	pub mod sr25519 {
+		mod app_sr25519 {
+			use sp_application_crypto::{app_crypto, key_types::IM_ONLINE, sr25519};
+			app_crypto!(sr25519, IM_ONLINE);
+		}
+		pub type AuthorityId = app_sr25519::Public;
+	}
+
+	#[frame_support::pallet]
+	pub mod pallet {
+		use super::*;
+		use frame_support::traits::{ValidatorSet, ValidatorSetWithIdentification};
+
+		#[pallet::pallet]
+		pub struct Pallet<T>(_);
+
+		#[pallet::config]
+		pub trait Config: frame_system::Config {
+			type RuntimeEvent: From<Event<Self>>
+				+ IsType<<Self as frame_system::Config>::RuntimeEvent>;
+			type ValidatorSet: ValidatorSetWithIdentification<Self::AccountId>;
+		}
+
+		pub type ValidatorId<T> = <<T as Config>::ValidatorSet as ValidatorSet<
+			<T as frame_system::Config>::AccountId,
+		>>::ValidatorId;
+
+		pub type IdentificationTuple<T> = (
+			ValidatorId<T>,
+			<<T as Config>::ValidatorSet as ValidatorSetWithIdentification<
+				<T as frame_system::Config>::AccountId,
+			>>::Identification,
+		);
+
+		#[pallet::event]
+		pub enum Event<T: Config> {
+			HeartbeatReceived { authority_id: super::sr25519::AuthorityId },
+			AllGood,
+			SomeOffline { offline: sp_std::vec::Vec<IdentificationTuple<T>> },
+		}
+	}
+}
+
+impl pallet_im_online::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type ValidatorSet = Historical;
+}
+
 construct_runtime! {
 	pub enum Runtime
 	{
@@ -1590,14 +1643,15 @@ construct_runtime! {
 
 		// Consensus support.
 		// Authorship must be before session in order to note author in the correct session and era
-		// for im-online and staking.
+		// for staking.
 		Authorship: pallet_authorship = 5,
 		Staking: pallet_staking = 6,
 		Offences: pallet_offences = 7,
 		Historical: session_historical = 34,
 
 		Session: pallet_session = 8,
 		Grandpa: pallet_grandpa = 10,
+		ImOnline: pallet_im_online::{Event<T>} = 11,
 		AuthorityDiscovery: pallet_authority_discovery = 12,
 
 		// Governance stuff.

diff --git a/relay/polkadot/Cargo.toml b/relay/polkadot/Cargo.toml
@@ -52,7 +52,6 @@ pallet-fast-unstake = { default-features = false , version = "28.0.0" }
 frame-executive = { default-features = false , version = "29.0.0" }
 pallet-grandpa = { default-features = false , version = "29.0.0" }
 pallet-identity = { default-features = false , version = "29.0.0" }
-pallet-im-online = { default-features = false , version = "28.0.0" }
 pallet-indices = { default-features = false , version = "29.0.0" }
 pallet-message-queue = { default-features = false , version = "32.0.0" }
 pallet-mmr = { default-features = false , version = "28.0.0" }
@@ -149,7 +148,6 @@ std = [
 	"pallet-fast-unstake/std",
 	"pallet-grandpa/std",
 	"pallet-identity/std",
-	"pallet-im-online/std",
 	"pallet-indices/std",
 	"pallet-message-queue/std",
 	"pallet-mmr/std",
@@ -221,7 +219,6 @@ runtime-benchmarks = [
 	"pallet-fast-unstake/runtime-benchmarks",
 	"pallet-grandpa/runtime-benchmarks",
 	"pallet-identity/runtime-benchmarks",
-	"pallet-im-online/runtime-benchmarks",
 	"pallet-indices/runtime-benchmarks",
 	"pallet-message-queue/runtime-benchmarks",
 	"pallet-mmr/runtime-benchmarks",
@@ -273,7 +270,6 @@ try-runtime = [
 	"pallet-fast-unstake/try-runtime",
 	"pallet-grandpa/try-runtime",
 	"pallet-identity/try-runtime",
-	"pallet-im-online/try-runtime",
 	"pallet-indices/try-runtime",
 	"pallet-message-queue/try-runtime",
 	"pallet-mmr/try-runtime",

diff --git a/relay/polkadot/src/lib.rs b/relay/polkadot/src/lib.rs
@@ -1553,6 +1553,59 @@ impl pallet_asset_rate::Config for Runtime {
 	type BenchmarkHelper = runtime_common::impls::benchmarks::AssetRateArguments;
 }
 
+// A mock pallet to keep `ImOnline` events decodable after pallet removal
+pub mod pallet_im_online {
+	use frame_support::pallet_prelude::*;
+	pub use pallet::*;
+
+	pub mod sr25519 {
+		mod app_sr25519 {
+			use sp_application_crypto::{app_crypto, key_types::IM_ONLINE, sr25519};
+			app_crypto!(sr25519, IM_ONLINE);
+		}
+		pub type AuthorityId = app_sr25519::Public;
+	}
+
+	#[frame_support::pallet]
+	pub mod pallet {
+		use super::*;
+		use frame_support::traits::{ValidatorSet, ValidatorSetWithIdentification};
+
+		#[pallet::pallet]
+		pub struct Pallet<T>(_);
+
+		#[pallet::config]
+		pub trait Config: frame_system::Config {
+			type RuntimeEvent: From<Event<Self>>
+				+ IsType<<Self as frame_system::Config>::RuntimeEvent>;
+			type ValidatorSet: ValidatorSetWithIdentification<Self::AccountId>;
+		}
+
+		pub type ValidatorId<T> = <<T as Config>::ValidatorSet as ValidatorSet<
+			<T as frame_system::Config>::AccountId,
+		>>::ValidatorId;
+
+		pub type IdentificationTuple<T> = (
+			ValidatorId<T>,
+			<<T as Config>::ValidatorSet as ValidatorSetWithIdentification<
+				<T as frame_system::Config>::AccountId,
+			>>::Identification,
+		);
+
+		#[pallet::event]
+		pub enum Event<T: Config> {
+			HeartbeatReceived { authority_id: super::sr25519::AuthorityId },
+			AllGood,
+			SomeOffline { offline: sp_std::vec::Vec<IdentificationTuple<T>> },
+		}
+	}
+}
+
+impl pallet_im_online::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type ValidatorSet = Historical;
+}
+
 construct_runtime! {
 	pub enum Runtime
 	{
@@ -1579,6 +1632,7 @@ construct_runtime! {
 
 		Session: pallet_session = 9,
 		Grandpa: pallet_grandpa = 11,
+		ImOnline: pallet_im_online::{Event<T>} = 12,
 		AuthorityDiscovery: pallet_authority_discovery = 13,
 
 		// OpenGov stuff.