REVERT ME: add tracing messages for GetBackedCandidates

Note that these messages are only sometimes actually passed on to the
candidate backing subsystem, with the consequence that it is
unexpectedly frequent that the provisioner fails to create its
provisionable data.

node/core/backing/src/lib.rs

@@ -515,22 +515,19 @@ impl CandidateBackingJob {
 					Ok(()) => (),
 				}
 			}
-			CandidateBackingMessage::GetBackedCandidates(_, requested_candidates, tx) => {
+			CandidateBackingMessage::GetBackedCandidates(relay_parent, requested_candidates, tx) => {
 				let _timer = self.metrics.time_get_backed_candidates();
 
+				tracing::info!(target: LOG_TARGET, relay_parent = ?relay_parent, "started handling GetBackedCandidates");
+
 				let backed: Vec<_> = self
 					.get_backed()
 					.filter(|candidate| requested_candidates.contains(&candidate.hash()))
 					.collect();
 
-				tracing::info!(
-					target: LOG_TARGET,
-					requested_candidates_len = requested_candidates.len(),
-					backed_len = backed.len(),
-					"got and filtered backed candidates",
-				);
-
 				tx.send(backed).map_err(|data| Error::Send(data))?;
+
+				tracing::info!(target: LOG_TARGET, relay_parent = ?relay_parent, "finished handling GetBackedCandidates");
 			}
 		}
 

node/core/provisioner/src/lib.rs

@@ -440,6 +440,7 @@ async fn select_candidates(
 	}
 
 	// now get the backed candidates corresponding to these candidate receipts
+	tracing::info!(target: LOG_TARGET, relay_parent = ?relay_parent, "requesting GetBackedCandidates");
 	let (tx, rx) = oneshot::channel();
 	sender.send(FromJob::CandidateBacking(CandidateBackingMessage::GetBackedCandidates(
 		relay_parent,

node/overseer/src/lib.rs

@@ -339,6 +339,11 @@ impl<M: Send + 'static> SubsystemContext for OverseerSubsystemContext<M> {
 	}
 
 	async fn send_message(&mut self, msg: AllMessages) -> SubsystemResult<()> {
+		{
+			if let AllMessages::CandidateBacking(CandidateBackingMessage::GetBackedCandidates(relay_parent, ..)) = &msg {
+				tracing::info!(target: LOG_TARGET, relay_parent = ?relay_parent, "OverseerSubsystemContext passing along CandidateBackingMessage::GetBackedCandidates");
+			}
+		}
 		self.tx.send(ToOverseer::SubsystemMessage(msg)).await.map_err(Into::into)
 	}