Prospective Parachains Subsystem

Cargo.toml

@@ -68,6 +68,7 @@ members = [
 	"node/core/chain-selection",
 	"node/core/dispute-coordinator",
 	"node/core/parachains-inherent",
+	"node/core/prospective-parachains",
 	"node/core/provisioner",
 	"node/core/pvf",
 	"node/core/pvf-checker",

node/core/prospective-parachains/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "polkadot-node-core-prospective-parachains"
+version = "0.9.16"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+futures = "0.3.19"
+gum = { package = "tracing-gum", path = "../../gum" }
+parity-scale-codec = "2"
+thiserror = "1.0.30"
+fatality = "0.0.6"
+bitvec = "1"
+
+polkadot-primitives = { path = "../../../primitives" }
+polkadot-node-primitives = { path = "../../primitives" }
+polkadot-node-subsystem = { path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
+
+[dev-dependencies]
+assert_matches = "1"
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
+
+[features]
+# If not enabled, the dispute coordinator will do nothing.
+disputes = []

node/core/prospective-parachains/src/error.rs

@@ -0,0 +1,83 @@
+// Copyright 2022 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Error types.
+
+use futures::channel::oneshot;
+
+use polkadot_node_subsystem::{
+	errors::{ChainApiError, RuntimeApiError},
+	SubsystemError,
+};
+
+use crate::LOG_TARGET;
+use fatality::Nested;
+
+#[allow(missing_docs)]
+#[fatality::fatality(splitable)]
+pub enum Error {
+	#[fatal]
+	#[error("SubsystemError::Context error: {0}")]
+	SubsystemContext(String),
+
+	#[fatal]
+	#[error("Spawning a task failed: {0}")]
+	SpawnFailed(SubsystemError),
+
+	#[fatal]
+	#[error("Participation worker receiver exhausted.")]
+	ParticipationWorkerReceiverExhausted,
+
+	#[fatal]
+	#[error("Receiving message from overseer failed: {0}")]
+	SubsystemReceive(#[source] SubsystemError),
+
+	#[error(transparent)]
+	RuntimeApi(#[from] RuntimeApiError),
+
+	#[error(transparent)]
+	ChainApi(#[from] ChainApiError),
+
+	#[error(transparent)]
+	Subsystem(SubsystemError),
+
+	#[error("Request to chain API subsystem dropped")]
+	ChainApiRequestCanceled(oneshot::Canceled),
+
+	#[error("Request to runtime API subsystem dropped")]
+	RuntimeApiRequestCanceled(oneshot::Canceled),
+}
+
+/// General `Result` type.
+pub type Result<R> = std::result::Result<R, Error>;
+/// Result for non-fatal only failures.
+pub type JfyiErrorResult<T> = std::result::Result<T, JfyiError>;
+/// Result for fatal only failures.
+pub type FatalResult<T> = std::result::Result<T, FatalError>;
+
+/// Utility for eating top level errors and log them.
+///
+/// We basically always want to try and continue on error. This utility function is meant to
+/// consume top-level errors by simply logging them
+pub fn log_error(result: Result<()>, ctx: &'static str) -> FatalResult<()> {
+	match result.into_nested()? {
+		Ok(()) => Ok(()),
+		Err(jfyi) => {
+			gum::debug!(target: LOG_TARGET, error = ?jfyi, ctx);
+			Ok(())
+		},
+	}
+}