Refactor beefy-mmr implementation (#4719)

* update pallet-beefy-mmr implementation

* minor fix

* fix build

* use H256 for rococo leaf extra

* update lockfile for {"substrate"}

* fix fmt

Co-authored-by: acatangiu <adrian@parity.io>

polkadot/bridges/bin/millau/runtime/src/lib.rs

@@ -32,7 +32,7 @@ pub mod rialto_messages;
 
 use crate::rialto_messages::{ToRialtoMessagePayload, WithRialtoMessageBridge};
 
-use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::MmrLeafVersion, ValidatorSet};
+use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::{MmrLeafVersion}, ValidatorSet};
 use bridge_runtime_common::messages::{
 	source::estimate_message_dispatch_and_delivery_fee, MessageBridge,
 };
@@ -281,7 +281,7 @@ parameter_types! {
 impl pallet_beefy_mmr::Config for Runtime {
 	type LeafVersion = LeafVersion;
 	type BeefyAuthorityToMerkleLeaf = pallet_beefy_mmr::BeefyEcdsaToEthereum;
-	type ParachainHeads = ();
+	type BeefyDataProvider = ();
 }
 
 parameter_types! {

polkadot/bridges/bin/rialto/runtime/src/lib.rs

@@ -33,7 +33,7 @@ pub mod parachains;
 
 use crate::millau_messages::{ToMillauMessagePayload, WithMillauMessageBridge};
 
-use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::MmrLeafVersion, ValidatorSet};
+use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::{MmrLeafVersion}, ValidatorSet};
 use bridge_runtime_common::messages::{
 	source::estimate_message_dispatch_and_delivery_fee, MessageBridge,
 };
@@ -280,10 +280,12 @@ impl pallet_grandpa::Config for Runtime {
 	type MaxAuthorities = MaxAuthorities;
 }
 
+type MmrHash = <Keccak256 as sp_runtime::traits::Hash>::Output;
+
 impl pallet_mmr::Config for Runtime {
 	const INDEXING_PREFIX: &'static [u8] = b"mmr";
 	type Hashing = Keccak256;
-	type Hash = <Keccak256 as sp_runtime::traits::Hash>::Output;
+	type Hash = MmrHash;
 	type OnNewRoot = pallet_beefy_mmr::DepositBeefyDigest<Runtime>;
 	type WeightInfo = ();
 	type LeafData = pallet_beefy_mmr::Pallet<Runtime>;
@@ -309,7 +311,7 @@ parameter_types! {
 impl pallet_beefy_mmr::Config for Runtime {
 	type LeafVersion = LeafVersion;
 	type BeefyAuthorityToMerkleLeaf = pallet_beefy_mmr::BeefyEcdsaToEthereum;
-	type ParachainHeads = ();
+	type BeefyDataProvider = ();
 }
 
 parameter_types! {

polkadot/runtime/rococo/Cargo.toml

@@ -30,6 +30,7 @@ offchain-primitives = { package = "sp-offchain", git = "https://github.com/parit
 
 babe-primitives = { package = "sp-consensus-babe", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 beefy-primitives = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+beefy-merkle-tree = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 frame-executive = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 pallet-authority-discovery = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 pallet-authorship = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }

polkadot/runtime/rococo/src/lib.rs

@@ -21,7 +21,10 @@
 #![recursion_limit = "256"]
 
 use authority_discovery_primitives::AuthorityId as AuthorityDiscoveryId;
-use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::MmrLeafVersion};
+use beefy_primitives::{
+	crypto::AuthorityId as BeefyId,
+	mmr::{BeefyDataProvider, MmrLeafVersion},
+};
 use frame_support::{
 	construct_runtime, parameter_types,
 	traits::{Contains, InstanceFilter, KeyOwnerProofSystem},
@@ -47,7 +50,7 @@ use runtime_common::{
 };
 use runtime_parachains::{self, runtime_api_impl::v2 as runtime_api_impl};
 use scale_info::TypeInfo;
-use sp_core::{OpaqueMetadata, RuntimeDebug};
+use sp_core::{OpaqueMetadata, RuntimeDebug, H256};
 use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
 	traits::{
@@ -673,25 +676,17 @@ impl pallet_beefy::Config for Runtime {
 	type BeefyId = BeefyId;
 }
 
+type MmrHash = <Keccak256 as sp_runtime::traits::Hash>::Output;
+
 impl pallet_mmr::Config for Runtime {
 	const INDEXING_PREFIX: &'static [u8] = b"mmr";
 	type Hashing = Keccak256;
-	type Hash = <Keccak256 as sp_runtime::traits::Hash>::Output;
+	type Hash = MmrHash;
 	type OnNewRoot = pallet_beefy_mmr::DepositBeefyDigest<Runtime>;
 	type WeightInfo = ();
 	type LeafData = pallet_beefy_mmr::Pallet<Runtime>;
 }
 
-pub struct ParasProvider;
-impl pallet_beefy_mmr::ParachainHeadsProvider for ParasProvider {
-	fn parachain_heads() -> Vec<(u32, Vec<u8>)> {
-		Paras::parachains()
-			.into_iter()
-			.filter_map(|id| Paras::para_head(&id).map(|head| (id.into(), head.0)))
-			.collect()
-	}
-}
-
 parameter_types! {
 	/// Version of the produced MMR leaf.
 	///
@@ -709,10 +704,26 @@ parameter_types! {
 	pub LeafVersion: MmrLeafVersion = MmrLeafVersion::new(0, 0);
 }
 
+pub struct ParasProvider;
+impl BeefyDataProvider<H256> for ParasProvider {
+	fn extra_data() -> H256 {
+		let mut para_heads: Vec<(u32, Vec<u8>)> = Paras::parachains()
+			.into_iter()
+			.filter_map(|id| Paras::para_head(&id).map(|head| (id.into(), head.0)))
+			.collect();
+		para_heads.sort();
+		beefy_merkle_tree::merkle_root::<pallet_beefy_mmr::Pallet<Runtime>, _, _>(
+			para_heads.into_iter().map(|pair| pair.encode()),
+		)
+		.into()
+	}
+}
+
 impl pallet_beefy_mmr::Config for Runtime {
 	type LeafVersion = LeafVersion;
 	type BeefyAuthorityToMerkleLeaf = pallet_beefy_mmr::BeefyEcdsaToEthereum;
-	type ParachainHeads = ParasProvider;
+	type LeafExtra = H256;
+	type BeefyDataProvider = ParasProvider;
 }
 
 parameter_types! {