Enable two phase election provider in runtimes in 'DryRun' mode (#2476)

* Apply some changes

* Make the runtimes build

* Master.into()

* Undo branch updates.

* Undo unwatned changes

* Fix deps one last time

* Fix election lookahead

* Revert deps

* Fix :P

Co-authored-by: Bastian Köcher <info@kchr.de>

polkadot/runtime/polkadot/Cargo.toml

@@ -40,6 +40,7 @@ pallet-transaction-payment-rpc-runtime-api = { git = "https://github.com/parityt
 pallet-collective = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 pallet-democracy = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 pallet-elections-phragmen = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+pallet-election-provider-multi-phase = { 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-grandpa = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 pallet-identity = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
@@ -112,6 +113,7 @@ std = [
 	"pallet-transaction-payment-rpc-runtime-api/std",
 	"pallet-collective/std",
 	"pallet-elections-phragmen/std",
+	"pallet-election-provider-multi-phase/std",
 	"pallet-democracy/std",
 	"frame-executive/std",
 	"pallet-grandpa/std",

polkadot/runtime/polkadot/src/lib.rs

@@ -124,7 +124,7 @@ impl Filter<Call> for BaseFilter {
 			Call::AuthorityDiscovery(_) |
 			Call::Utility(_) | Call::Claims(_) | Call::Vesting(_) |
 			Call::Identity(_) | Call::Proxy(_) | Call::Multisig(_) |
-			Call::Bounties(_) | Call::Tips(_)
+			Call::Bounties(_) | Call::Tips(_) | Call::ElectionProviderMultiPhase(_)
 			=> true,
 		}
 	}
@@ -308,6 +308,41 @@ impl pallet_session::historical::Config for Runtime {
 	type FullIdentificationOf = pallet_staking::ExposureOf<Runtime>;
 }
 
+parameter_types! {
+	// no signed phase for now, just unsigned.
+	pub const SignedPhase: u32 = 0;
+	// NOTE: length of unsigned phase is, for now, different than `ElectionLookahead` to make sure
+	// that we won't run OCW threads at the same time with staking.
+	pub const UnsignedPhase: u32 = ElectionLookahead::get() / 2;
+
+	// fallback: no need to do on-chain phragmen while we re on a dry-run.
+	pub const Fallback: pallet_election_provider_multi_phase::FallbackStrategy =
+		pallet_election_provider_multi_phase::FallbackStrategy::Nothing;
+
+	pub SolutionImprovementThreshold: Perbill = Perbill::from_rational_approximation(1u32, 10_000);
+
+	// miner configs
+	pub MultiPhaseUnsignedPriority: TransactionPriority = StakingUnsignedPriority::get() - 1u64;
+	pub const MinerMaxIterations: u32 = 10;
+}
+
+impl pallet_election_provider_multi_phase::Config for Runtime {
+	type Event = Event;
+	type Currency = Balances;
+	type SignedPhase = SignedPhase;
+	type UnsignedPhase = UnsignedPhase;
+	type SolutionImprovementThreshold = MinSolutionScoreBump;
+	type MinerMaxIterations = MinerMaxIterations;
+	type MinerMaxWeight = OffchainSolutionWeightLimit; // For now use the one from staking.
+	type MinerTxPriority = MultiPhaseUnsignedPriority;
+	type DataProvider = Staking;
+	type OnChainAccuracy = Perbill;
+	type CompactSolution = pallet_staking::CompactAssignments;
+	type Fallback = Fallback;
+	type WeightInfo = pallet_election_provider_multi_phase::weights::SubstrateWeight<Runtime>;
+	type BenchmarkingConfig = ();
+}
+
 // TODO #6469: This shouldn't be static, but a lazily cached value, not built unless needed, and
 // re-built in case input parameters have changed. The `ideal_stake` should be determined by the
 // amount of parachain slots being bid on: this should be around `(75 - 25.min(slots / 4))%`.
@@ -369,6 +404,7 @@ impl pallet_staking::Config for Runtime {
 	// The unsigned solution weight targeted by the OCW. We set it to the maximum possible value of
 	// a single extrinsic.
 	type OffchainSolutionWeightLimit = OffchainSolutionWeightLimit;
+	type ElectionProvider = ElectionProviderMultiPhase;
 	type WeightInfo = weights::pallet_staking::WeightInfo<Runtime>;
 }
 
@@ -989,6 +1025,9 @@ construct_runtime! {
 		// Tips module.
 		Tips: pallet_tips::{Module, Call, Storage, Event<T>} = 35,
 
+		// Election pallet. Only works with staking, but placed here to maintain indices.
+		ElectionProviderMultiPhase: pallet_election_provider_multi_phase::{Module, Call, Storage, Event<T>, ValidateUnsigned} = 36,
+
 	}
 }