Switch elections to Phragmen, enable them in PoA (#492)

* Switch elections to Phragmen, enable them in PoA

* Remove superfluous code.

* Build fixes

* Update to substrate master

* Build fixes

* Add warning

* Disable authority discovery for now

* Remove commented code

* Fix warning

polkadot/runtime/src/lib.rs

@@ -48,8 +48,7 @@ use sr_primitives::{
 };
 use version::RuntimeVersion;
 use grandpa::{AuthorityId as GrandpaId, fg_primitives};
-use babe_primitives::{AuthorityId as BabeId, AuthoritySignature as BabeSignature};
-use elections::VoteIndex;
+use babe_primitives::{AuthorityId as BabeId};
 #[cfg(any(feature = "std", test))]
 use version::NativeVersion;
 use substrate_primitives::OpaqueMetadata;
@@ -57,7 +56,6 @@ use sr_staking_primitives::SessionIndex;
 use srml_support::{
 	parameter_types, construct_runtime, traits::{SplitTwoWays, Currency, Randomness}
 };
-use authority_discovery_primitives::{AuthorityId as EncodedAuthorityId, Signature as EncodedSignature};
 use im_online::sr25519::AuthorityId as ImOnlineId;
 use system::offchain::TransactionSubmitter;
 
@@ -72,7 +70,7 @@ pub use parachains::{Call as ParachainsCall, NEW_HEADS_IDENTIFIER};
 
 /// Implementations of some helper traits passed into runtime modules as associated types.
 pub mod impls;
-use impls::{CurrencyToVoteHandler, FeeMultiplierUpdateHandler, ToAuthor, WeightToFee};
+use impls::{CurrencyToVoteHandler, TargetedFeeAdjustment, ToAuthor, WeightToFee};
 
 /// Constant values used within the runtime.
 pub mod constants;
@@ -131,7 +129,9 @@ impl SignedExtension for OnlyStakingAndClaims {
 		-> TransactionValidity
 	{
 		match call {
-			Call::Staking(_) | Call::Claims(_) | Call::Sudo(_) | Call::Session(_) =>
+			Call::Staking(_) | Call::Claims(_) | Call::Sudo(_) | Call::Session(_)
+				| Call::ElectionsPhragmen(_)
+			=>
 				Ok(Default::default()),
 			_ => Err(InvalidTransaction::Custom(ValidityError::NoPermission.into()).into()),
 		}
@@ -215,6 +215,8 @@ impl balances::Trait for Runtime {
 parameter_types! {
 	pub const TransactionBaseFee: Balance = 1 * CENTS;
 	pub const TransactionByteFee: Balance = 10 * MILLICENTS;
+	// for a sane configuration, this should always be less than `AvailableBlockRatio`.
+	pub const TargetBlockFullness: Perbill = Perbill::from_percent(25);
 }
 
 impl transaction_payment::Trait for Runtime {
@@ -223,7 +225,7 @@ impl transaction_payment::Trait for Runtime {
 	type TransactionBaseFee = TransactionBaseFee;
 	type TransactionByteFee = TransactionByteFee;
 	type WeightToFee = WeightToFee;
-	type FeeMultiplierUpdate = FeeMultiplierUpdateHandler;
+	type FeeMultiplierUpdate = TargetedFeeAdjustment<TargetBlockFullness>;
 }
 
 parameter_types! {
@@ -252,7 +254,10 @@ parameter_types! {
 	pub const Offset: BlockNumber = 0;
 }
 
-type SessionHandlers = (Grandpa, Babe, ImOnline, AuthorityDiscovery, Parachains);
+// !!!!!!!!!!!!!
+// WARNING!!!!!!  SEE NOTE BELOW BEFORE TOUCHING THIS CODE
+// !!!!!!!!!!!!!
+type SessionHandlers = (Grandpa, Babe, ImOnline, Parachains);
 impl_opaque_keys! {
 	pub struct SessionKeys {
 		#[id(key_types::GRANDPA)]
@@ -265,7 +270,6 @@ impl_opaque_keys! {
 		pub parachain_validator: parachain::ValidatorId,
 	}
 }
-
 // NOTE: `SessionHandler` and `SessionKeys` are co-dependent: One key will be used for each handler.
 // The number and order of items in `SessionHandler` *MUST* be the same number and order of keys in
 // `SessionKeys`.
@@ -370,35 +374,20 @@ impl collective::Trait<CouncilCollective> for Runtime {
 }
 
 parameter_types! {
-	pub const CandidacyBond: Balance = 10 * DOLLARS;
-	pub const VotingBond: Balance = 1 * DOLLARS;
-	pub const VotingFee: Balance = 2 * DOLLARS;
-	pub const MinimumVotingLock: Balance = 1 * DOLLARS;
-	pub const PresentSlashPerVoter: Balance = 1 * CENTS;
-	pub const CarryCount: u32 = 6;
-	// one additional vote should go by before an inactive voter can be reaped.
-	pub const InactiveGracePeriod: VoteIndex = 1;
-	pub const ElectionsVotingPeriod: BlockNumber = 2 * DAYS;
-	pub const DecayRatio: u32 = 0;
+	pub const CandidacyBond: Balance = 100 * DOLLARS;
+	pub const VotingBond: Balance = 5 * DOLLARS;
 }
 
-impl elections::Trait for Runtime {
+impl elections_phragmen::Trait for Runtime {
 	type Event = Event;
 	type Currency = Balances;
-	type BadPresentation = ();
-	type BadReaper = ();
-	type BadVoterIndex = ();
-	type LoserCandidate = ();
 	type ChangeMembers = Council;
+	type CurrencyToVote = CurrencyToVoteHandler;
 	type CandidacyBond = CandidacyBond;
 	type VotingBond = VotingBond;
-	type VotingFee = VotingFee;
-	type MinimumVotingLock = MinimumVotingLock;
-	type PresentSlashPerVoter = PresentSlashPerVoter;
-	type CarryCount = CarryCount;
-	type InactiveGracePeriod = InactiveGracePeriod;
-	type VotingPeriod = ElectionsVotingPeriod;
-	type DecayRatio = DecayRatio;
+	type LoserCandidate = Treasury;
+	type BadReport = Treasury;
+	type KickedMember = Treasury;
 }
 
 type TechnicalCollective = collective::Instance2;
@@ -454,10 +443,6 @@ impl im_online::Trait for Runtime {
 	type ReportUnresponsiveness = ();
 }
 
-impl authority_discovery::Trait for Runtime {
-    type AuthorityId = BabeId;
-}
-
 impl grandpa::Trait for Runtime {
 	type Event = Event;
 }
@@ -566,13 +551,12 @@ construct_runtime!(
 		FinalityTracker: finality_tracker::{Module, Call, Inherent},
 		Grandpa: grandpa::{Module, Call, Storage, Config, Event},
 		ImOnline: im_online::{Module, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
-		AuthorityDiscovery: authority_discovery::{Module, Call, Config<T>},
 
 		// Governance stuff; uncallable initially.
 		Democracy: democracy::{Module, Call, Storage, Config, Event<T>},
 		Council: collective::<Instance1>::{Module, Call, Storage, Origin<T>, Event<T>, Config<T>},
 		TechnicalCommittee: collective::<Instance2>::{Module, Call, Storage, Origin<T>, Event<T>, Config<T>},
-		Elections: elections::{Module, Call, Storage, Event<T>, Config<T>},
+		ElectionsPhragmen: elections_phragmen::{Module, Call, Storage, Event<T>, Config<T>},
 		TechnicalMembership: membership::<Instance1>::{Module, Call, Storage, Event<T>, Config<T>},
 		Treasury: treasury::{Module, Call, Storage, Event<T>},
 
@@ -723,36 +707,6 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl authority_discovery_primitives::AuthorityDiscoveryApi<Block> for Runtime {
-		fn authorities() -> Vec<EncodedAuthorityId> {
-			AuthorityDiscovery::authorities().into_iter()
-				.map(|id| id.encode())
-				.map(EncodedAuthorityId)
-				.collect()
-		}
-
-		fn sign(payload: &Vec<u8>) -> Option<(EncodedSignature, EncodedAuthorityId)> {
-			AuthorityDiscovery::sign(payload).map(|(sig, id)| {
-				(EncodedSignature(sig.encode()), EncodedAuthorityId(id.encode()))
-			})
-		}
-
-		fn verify(payload: &Vec<u8>, signature: &EncodedSignature, authority_id: &EncodedAuthorityId) -> bool {
-			let signature = match BabeSignature::decode(&mut &signature.0[..]) {
-				Ok(s) => s,
-				_ => return false,
-			};
-
-			let authority_id = match BabeId::decode(&mut &authority_id.0[..]) {
-				Ok(id) => id,
-				_ => return false,
-			};
-
-			AuthorityDiscovery::verify(payload, signature, authority_id)
-
-		}
-	}
-
 	impl substrate_session::SessionKeys<Block> for Runtime {
 		fn generate_session_keys(seed: Option<Vec<u8>>) -> Vec<u8> {
 			let seed = seed.as_ref().map(|s| rstd::str::from_utf8(&s).expect("Seed is an utf8 string"));