Clean up allocations in internal_peer_storage_retrieval

Clarifies some log messages and removes some unecessary allocations
in both happy and error paths.

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -8547,36 +8547,31 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 	}
 
 	#[rustfmt::skip]
-	fn internal_peer_storage_retrieval(&self, counterparty_node_id: PublicKey, msg: msgs::PeerStorageRetrieval) -> Result<(), MsgHandleErrInternal> {
+	fn internal_peer_storage_retrieval(&self, peer_node_id: PublicKey, msg: msgs::PeerStorageRetrieval) -> Result<(), MsgHandleErrInternal> {
 		// TODO: Check if have any stale or missing ChannelMonitor.
-		let logger = WithContext::from(&self.logger, Some(counterparty_node_id), None, None);
-		let err = MsgHandleErrInternal::from_chan_no_close(
+		let logger = WithContext::from(&self.logger, Some(peer_node_id), None, None);
+		let err = || MsgHandleErrInternal::from_chan_no_close(
 			ChannelError::Ignore("Invalid PeerStorageRetrieval message received.".into()),
 			ChannelId([0; 32]),
 		);
-		let err_str = || {
-			format!("Invalid PeerStorage received from {}", counterparty_node_id)
-		};
 
 		let encrypted_ops = match EncryptedOurPeerStorage::new(msg.data) {
 			Ok(encrypted_ops) => encrypted_ops,
-			Err(_) => {
-				log_debug!(logger, "{}", err_str());
-				return Err(err);
+			Err(()) => {
+				log_debug!(logger, "Received a peer backup which wasn't long enough to be valid");
+				return Err(err());
 			}
 		};
 
-		let decrypted_data = match encrypted_ops.decrypt(&self.node_signer.get_peer_storage_key()) {
+		let decrypted = match encrypted_ops.decrypt(&self.node_signer.get_peer_storage_key()) {
 			Ok(decrypted_ops) => decrypted_ops.into_vec(),
-			Err(_) => {
-				log_debug!(logger, "{}", err_str());
-				return Err(err);
+			Err(()) => {
+				log_debug!(logger, "Received a peer backup which was corrupted");
+				return Err(err());
 			}
 		};
 
-		if decrypted_data.is_empty() {
-			log_debug!(logger, "Received a peer storage from peer {} with 0 channels.", log_pubkey!(counterparty_node_id));
-		}
+		log_trace!(logger, "Got valid {}-byte peer backup from {}", decrypted.len(), peer_node_id);
 
 		Ok(())
 	}