Make `collator::Network` require `Send + Sync` to make it work (#316)

collator/src/lib.rs

@@ -79,7 +79,7 @@ pub use substrate_network::PeerId;
 const COLLATION_TIMEOUT: Duration = Duration::from_secs(30);
 
 /// An abstraction over the `Network` with useful functions for a `Collator`.
-pub trait Network {
+pub trait Network: Send + Sync {
 	/// Convert the given `CollatorId` to a `PeerId`.
 	fn collator_id_to_peer_id(&self, collator_id: CollatorId) ->
 		Box<dyn Future<Item=Option<PeerId>, Error=()> + Send>;
@@ -93,8 +93,8 @@ pub trait Network {
 }
 
 impl<P, E> Network for ValidationNetwork<P, E, NetworkService, TaskExecutor> where
-	P: 'static,
-	E: 'static,
+	P: 'static + Send + Sync,
+	E: 'static + Send + Sync,
 {
 	fn collator_id_to_peer_id(&self, collator_id: CollatorId) ->
 		Box<dyn Future<Item=Option<PeerId>, Error=()> + Send>
@@ -438,7 +438,7 @@ pub fn run_collator<P, E, I, ArgT>(
 	P: BuildParachainContext + Send + 'static,
 	P::ParachainContext: Send + 'static,
 	<<P::ParachainContext as ParachainContext>::ProduceCandidate as IntoFuture>::Future: Send + 'static,
-	E: IntoFuture<Item=(),Error=()>,
+	E: IntoFuture<Item=(), Error=()>,
 	E::Future: Send + Clone + Sync + 'static,
 	I: IntoIterator<Item=ArgT>,
 	ArgT: Into<std::ffi::OsString> + Clone,

test-parachains/adder/collator/src/main.rs

@@ -47,6 +47,8 @@ const GENESIS_BODY: AdderBody = AdderBody {
 #[derive(Clone)]
 struct AdderContext {
 	db: Arc<Mutex<HashMap<AdderHead, AdderBody>>>,
+	/// We store it here to make sure that our interfaces require the correct bounds.
+	_network: Option<Arc<dyn Network>>,
 }
 
 /// The parachain context.
@@ -99,8 +101,8 @@ impl ParachainContext for AdderContext {
 impl BuildParachainContext for AdderContext {
 	type ParachainContext = Self;
 
-	fn build(self, _: Arc<dyn Network>) -> Result<Self::ParachainContext, ()> {
-		Ok(self)
+	fn build(self, network: Arc<dyn Network>) -> Result<Self::ParachainContext, ()> {
+		Ok(Self { _network: Some(network), ..self })
 	}
 }
 
@@ -133,6 +135,7 @@ fn main() {
 
 	let context = AdderContext {
 		db: Arc::new(Mutex::new(HashMap::new())),
+		_network: None,
 	};
 
 	let res = ::collator::run_collator(