feat: add feasibility_check on mined solution (#483)

* feat: add `feasibility_check` on mined solution

* update substrate

* update metadata

* fix miner tests

* update staking miner playground

* remove noise

* simplify code, remove DRY code

* Update src/epm.rs

Cargo.toml

@@ -19,16 +19,18 @@ tokio = { version = "1.27", features = ["macros", "rt-multi-thread", "sync", "si
 pin-project-lite = "0.2"
 
 # subxt
-subxt = "0.27.1"
+subxt = { git = "https://github.com/paritytech/subxt" }
 scale-value = "0.6.0"
 
 # substrate
-frame-election-provider-support = "16.0.0"
-pallet-election-provider-multi-phase = "15.0.0"
-sp-npos-elections = "14.0.0"
-frame-support = "16.0.0"
-sp-core = "16.0.0"
-sp-runtime = "18.0.0"
+sp-io = { git = "https://github.com/paritytech/substrate" }
+frame-system = { git = "https://github.com/paritytech/substrate" }
+frame-election-provider-support = { git = "https://github.com/paritytech/substrate" }
+pallet-election-provider-multi-phase = { git = "https://github.com/paritytech/substrate" }
+sp-npos-elections = { git = "https://github.com/paritytech/substrate" }
+frame-support = { git = "https://github.com/paritytech/substrate" }
+sp-version = { git = "https://github.com/paritytech/substrate" }
+sp-runtime = { git = "https://github.com/paritytech/substrate" }
 
 # prometheus
 prometheus = "0.13"
@@ -38,7 +40,6 @@ once_cell = "1.17"
 [dev-dependencies]
 assert_cmd = "2.0"
 sp-storage = "11.0.0"
-sp-keyring = "18.0.0"
 regex = "1"
 
 [features]

src/dry_run.rs

@@ -41,8 +41,15 @@ where
 
 	log::info!(target: LOG_TARGET, "Loaded account {}, {:?}", signer, account_info);
 
+	let round = api
+		.storage()
+		.at(config.at)
+		.await?
+		.fetch_or_default(&runtime::storage().election_provider_multi_phase().round())
+		.await?;
+
 	let (solution, score, _size) =
-		epm::fetch_snapshot_and_mine_solution::<T>(&api, config.at, config.solver).await?;
+		epm::fetch_snapshot_and_mine_solution::<T>(&api, config.at, config.solver, round).await?;
 
 	let round = api
 		.storage()

src/epm.rs

@@ -19,9 +19,8 @@
 use crate::{helpers::RuntimeDispatchInfo, opt::Solver, prelude::*, static_types};
 use codec::{Decode, Encode};
 use frame_election_provider_support::{NposSolution, PhragMMS, SequentialPhragmen};
-use frame_support::{weights::Weight, BoundedVec};
+use frame_support::weights::Weight;
 use pallet_election_provider_multi_phase::{RawSolution, SolutionOf, SolutionOrSnapshotSize};
-use runtime::runtime_types::pallet_election_provider_multi_phase::RoundSnapshot;
 use scale_info::{PortableRegistry, TypeInfo};
 use scale_value::scale::{decode_as_type, TypeId};
 use sp_core::Bytes;
@@ -30,6 +29,11 @@ use subxt::{dynamic::Value, rpc::rpc_params, tx::DynamicTxPayload};
 
 const EPM_PALLET_NAME: &str = "ElectionProviderMultiPhase";
 
+type MinerVoterOf =
+	frame_election_provider_support::Voter<AccountId, crate::static_types::MaxVotesPerVoter>;
+
+type RoundSnapshot = pallet_election_provider_multi_phase::RoundSnapshot<AccountId, MinerVoterOf>;
+
 #[derive(Copy, Clone, Debug)]
 struct EpmConstant {
 	epm: &'static str,
@@ -57,33 +61,26 @@ pub(crate) async fn update_metadata_constants(api: &SubxtClient) -> Result<(), E
 	const SIGNED_MAX_WEIGHT: EpmConstant = EpmConstant::new("SignedMaxWeight");
 	const MAX_LENGTH: EpmConstant = EpmConstant::new("MinerMaxLength");
 	const MAX_VOTES_PER_VOTER: EpmConstant = EpmConstant::new("MinerMaxVotesPerVoter");
+	const MAX_WINNERS: EpmConstant = EpmConstant::new("MinerMaxWinners");
+
+	fn log_metadata(metadata: EpmConstant, val: impl std::fmt::Display) {
+		log::trace!(target: LOG_TARGET, "updating metadata constant `{metadata}`: {val}",);
+	}
 
 	let max_weight = read_constant::<Weight>(api, SIGNED_MAX_WEIGHT)?;
 	let max_length: u32 = read_constant(api, MAX_LENGTH)?;
 	let max_votes_per_voter: u32 = read_constant(api, MAX_VOTES_PER_VOTER)?;
+	let max_winners: u32 = read_constant(api, MAX_WINNERS)?;
 
-	log::trace!(
-		target: LOG_TARGET,
-		"updating metadata constant `{}`: {}",
-		SIGNED_MAX_WEIGHT.to_string(),
-		max_weight.ref_time()
-	);
-	log::trace!(
-		target: LOG_TARGET,
-		"updating metadata constant `{}`: {}",
-		MAX_LENGTH.to_string(),
-		max_length
-	);
-	log::trace!(
-		target: LOG_TARGET,
-		"updating metadata constant `{}`: {}",
-		MAX_VOTES_PER_VOTER.to_string(),
-		max_votes_per_voter
-	);
+	log_metadata(SIGNED_MAX_WEIGHT, max_weight);
+	log_metadata(MAX_LENGTH, max_length);
+	log_metadata(MAX_VOTES_PER_VOTER, max_votes_per_voter);
+	log_metadata(MAX_WINNERS, max_winners);
 
 	static_types::MaxWeight::set(max_weight);
 	static_types::MaxLength::set(max_length);
 	static_types::MaxVotesPerVoter::set(max_votes_per_voter);
+	static_types::MaxWinners::set(max_winners);
 
 	Ok(())
 }
@@ -150,12 +147,28 @@ pub async fn signed_submission_at<S: NposSolution + Decode + TypeInfo + 'static>
 	}
 }
 
+/// Helper to the signed submissions at the block `at`.
+pub async fn snapshot_at(at: Option<Hash>, api: &SubxtClient) -> Result<RoundSnapshot, Error> {
+	let empty = Vec::<Value>::new();
+	let addr = subxt::dynamic::storage(EPM_PALLET_NAME, "Snapshot", empty);
+
+	match api.storage().at(at).await?.fetch(&addr).await {
+		Ok(Some(val)) => {
+			let snapshot = Decode::decode(&mut val.encoded())?;
+			Ok(snapshot)
+		},
+		Ok(None) => Err(Error::EmptySnapshot),
+		Err(err) => Err(err.into()),
+	}
+}
+
 /// Helper to fetch snapshot data via RPC
 /// and compute an NPos solution via [`pallet_election_provider_multi_phase`].
 pub async fn fetch_snapshot_and_mine_solution<T>(
 	api: &SubxtClient,
 	hash: Option<Hash>,
 	solver: Solver,
+	round: u32,
 ) -> Result<(SolutionOf<T>, ElectionScore, SolutionOrSnapshotSize), Error>
 where
 	T: MinerConfig<AccountId = AccountId, MaxVotesPerVoter = static_types::MaxVotesPerVoter>
@@ -164,31 +177,24 @@ where
 		+ 'static,
 	T::Solution: Send,
 {
-	let RoundSnapshot { voters, targets } = api
+	let snapshot = snapshot_at(hash, &api).await?;
+	let desired_targets = api
 		.storage()
 		.at(hash)
 		.await?
-		.fetch(&runtime::storage().election_provider_multi_phase().snapshot())
+		.fetch(&runtime::storage().election_provider_multi_phase().desired_targets())
 		.await?
-		.unwrap_or_default();
+		.expect("Snapshot is non-empty; `desired_target` should exist; qed");
 
-	let desired_targets = api
+	let minimum_untrusted_score = api
 		.storage()
 		.at(hash)
 		.await?
-		.fetch(&runtime::storage().election_provider_multi_phase().desired_targets())
-		.await?
-		.unwrap_or_default();
-
-	let voters: Vec<_> = voters
-	.into_iter()
-	.map(|(a, b, mut c)| {
-		let mut bounded_vec: BoundedVec<AccountId, static_types::MaxVotesPerVoter> = BoundedVec::default();
-		// If this fails just crash the task.
-		bounded_vec.try_append(&mut c.0).unwrap_or_else(|_| panic!("BoundedVec capacity: {} failed; `MinerConfig::MaxVotesPerVoter` is different from the chain data; this is a bug please file an issue", static_types::MaxVotesPerVoter::get()));
-		(a, b, bounded_vec)
-	})
-	.collect();
+		.fetch(&runtime::storage().election_provider_multi_phase().minimum_untrusted_score())
+		.await?;
+
+	let voters = snapshot.voters.clone();
+	let targets = snapshot.targets.clone();
 
 	let blocking_task = tokio::task::spawn_blocking(move || match solver {
 		Solver::SeqPhragmen { iterations } => {
@@ -209,9 +215,24 @@ where
 	.await;
 
 	match blocking_task {
-		Ok(Ok(res)) => Ok(res),
+		Ok(Ok((solution, score, solution_or_snapshot))) => {
+			match Miner::<T>::feasibility_check(
+				RawSolution { solution: solution.clone(), score, round },
+				pallet_election_provider_multi_phase::ElectionCompute::Signed,
+				desired_targets,
+				snapshot,
+				round,
+				minimum_untrusted_score,
+			) {
+				Ok(_) => Ok((solution, score, solution_or_snapshot)),
+				Err(e) => {
+					log::error!(target: LOG_TARGET, "Solution feasibility error {:?}", e);
+					Err(Error::Feasibility(format!("{:?}", e)))
+				},
+			}
+		},
 		Ok(Err(err)) => Err(Error::Other(format!("{:?}", err))),
-		Err(err) => Err(Error::Other(format!("{:?}", err))),
+		Err(err) => Err(err.into()),
 	}
 }
 
@@ -278,14 +299,18 @@ pub async fn runtime_api_solution_weight<S: Encode + NposSolution + TypeInfo + '
 }
 
 /// Helper to mock the votes based on `voters` and `desired_targets`.
-pub fn mock_votes(voters: u32, desired_targets: u16) -> Vec<(u32, u16)> {
-	assert!(voters >= desired_targets as u32);
-	(0..voters).zip((0..desired_targets).cycle()).collect()
+pub fn mock_votes(voters: u32, desired_targets: u16) -> Option<Vec<(u32, u16)>> {
+	if voters >= desired_targets as u32 {
+		Some((0..voters).zip((0..desired_targets).cycle()).collect())
+	} else {
+		None
+	}
 }
 
 #[cfg(test)]
 #[test]
 fn mock_votes_works() {
-	assert_eq!(mock_votes(3, 2), vec![(0, 0), (1, 1), (2, 0)]);
-	assert_eq!(mock_votes(3, 3), vec![(0, 0), (1, 1), (2, 2)]);
+	assert_eq!(mock_votes(3, 2), Some(vec![(0, 0), (1, 1), (2, 0)]));
+	assert_eq!(mock_votes(3, 3), Some(vec![(0, 0), (1, 1), (2, 2)]));
+	assert_eq!(mock_votes(2, 3), None);
 }

src/error.rs

@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
+use crate::prelude::*;
+
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
 	#[error("Failed to parse log directive: `{0}´")]
@@ -48,4 +50,10 @@ pub enum Error {
 	SubscriptionClosed,
 	#[error("Dynamic transaction error: {0}")]
 	DynamicTransaction(String),
+	#[error("Feasibility error: {0}")]
+	Feasibility(String),
+	#[error("{0}")]
+	JoinError(#[from] tokio::task::JoinError),
+	#[error("Empty snapshot")]
+	EmptySnapshot,
 }

src/helpers.rs

@@ -14,8 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
+use crate::{error::Error, prelude::*};
 use codec::Decode;
 use frame_support::weights::Weight;
+use jsonrpsee::{core::Error as JsonRpseeError, types::error::CallError};
 use pin_project_lite::pin_project;
 use serde::Deserialize;
 use std::{
@@ -24,6 +26,7 @@ use std::{
 	task::{Context, Poll},
 	time::{Duration, Instant},
 };
+use subxt::error::{Error as SubxtError, RpcError};
 
 pin_project! {
 	pub struct Timed<Fut>
@@ -73,3 +76,65 @@ pub struct RuntimeDispatchInfo {
 	/// Weight of this dispatch.
 	pub weight: Weight,
 }
+
+pub fn kill_main_task_if_critical_err(tx: &tokio::sync::mpsc::UnboundedSender<Error>, err: Error) {
+	match err {
+		Error::AlreadySubmitted |
+		Error::BetterScoreExist |
+		Error::IncorrectPhase |
+		Error::TransactionRejected(_) |
+		Error::JoinError(_) |
+		Error::Feasibility(_) |
+		Error::EmptySnapshot |
+		Error::SubscriptionClosed => {},
+		Error::Subxt(SubxtError::Rpc(rpc_err)) => {
+			log::debug!(target: LOG_TARGET, "rpc error: {:?}", rpc_err);
+
+			match rpc_err {
+				RpcError::ClientError(e) => {
+					let jsonrpsee_err = match e.downcast::<JsonRpseeError>() {
+						Ok(e) => *e,
+						Err(_) => {
+							let _ = tx.send(Error::Other(
+								"Failed to downcast RPC error; this is a bug please file an issue"
+									.to_string(),
+							));
+							return
+						},
+					};
+
+					match jsonrpsee_err {
+						JsonRpseeError::Call(CallError::Custom(e)) => {
+							const BAD_EXTRINSIC_FORMAT: i32 = 1001;
+							const VERIFICATION_ERROR: i32 = 1002;
+							use jsonrpsee::types::error::ErrorCode;
+
+							// Check if the transaction gets fatal errors from the `author` RPC.
+							// It's possible to get other errors such as outdated nonce and similar
+							// but then it should be possible to try again in the next block or round.
+							if e.code() == BAD_EXTRINSIC_FORMAT ||
+								e.code() == VERIFICATION_ERROR || e.code() ==
+								ErrorCode::MethodNotFound.code()
+							{
+								let _ = tx.send(Error::Subxt(SubxtError::Rpc(
+									RpcError::ClientError(Box::new(CallError::Custom(e))),
+								)));
+							}
+						},
+						JsonRpseeError::Call(CallError::Failed(_)) => {},
+						JsonRpseeError::RequestTimeout => {},
+						err => {
+							let _ = tx.send(Error::Subxt(SubxtError::Rpc(RpcError::ClientError(
+								Box::new(err),
+							))));
+						},
+					}
+				},
+				RpcError::SubscriptionDropped => (),
+			}
+		},
+		err => {
+			let _ = tx.send(err);
+		},
+	}
+}