Make sure collators join the validation network (#1010)

Collators need to join the validation network to tell its connected
relay chain peers the leaf they listen on. This is required to make the
Parachain validator send the signed statement to the collators as well.

polkadot/service/src/lib.rs

@@ -320,9 +320,12 @@ pub fn westend_new_full(
 /// Handles to other sub-services that full nodes instantiate, which consumers
 /// of the node may use.
 #[cfg(feature = "full-node")]
+#[derive(Default)]
 pub struct FullNodeHandles {
 	/// A handle to the Polkadot networking protocol.
 	pub polkadot_network: Option<network_protocol::Service>,
+	/// A handle to the validation service.
+	pub validation_service_handle: Option<consensus::ServiceHandle>,
 }
 
 /// Builds a new service for a full client.
@@ -389,7 +392,7 @@ pub fn new_full<Runtime, Dispatch, Extrinsic>(
 	let client = service.client();
 	let known_oracle = client.clone();
 
-	let mut handles = FullNodeHandles { polkadot_network: None };
+	let mut handles = FullNodeHandles::default();
 	let select_chain = if let Some(select_chain) = service.select_chain() {
 		select_chain
 	} else {
@@ -427,7 +430,7 @@ pub fn new_full<Runtime, Dispatch, Extrinsic>(
 		service.spawn_task_handle(),
 	).map_err(|e| format!("Could not spawn network worker: {:?}", e))?;
 
-	if let Role::Authority { .. } = &role {
+	let authority_handles = if is_collator || role.is_authority() {
 		let availability_store = {
 			use std::path::PathBuf;
 
@@ -464,6 +467,18 @@ pub fn new_full<Runtime, Dispatch, Extrinsic>(
 
 		service.spawn_essential_task("validation-service", Box::pin(validation_service));
 
+		handles.validation_service_handle = Some(validation_service_handle.clone());
+
+		Some((validation_service_handle, availability_store))
+	} else {
+		None
+	};
+
+	if role.is_authority() {
+		let (validation_service_handle, availability_store) = authority_handles
+			.clone()
+			.expect("Authority handles are set for authority nodes; qed");
+
 		let proposer = consensus::ProposerFactory::new(
 			client.clone(),
 			service.transaction_pool(),