From 7e0d0502aa057c6033187fec97fbb11c8cf93ab3 Mon Sep 17 00:00:00 2001
From: Preston Van Loon <preston@prysmaticlabs.com>
Date: Sun, 9 Feb 2020 00:41:50 -0800
Subject: [PATCH] Prevent panic on wrong interface conversion (#4803)

* Prevent panic on wrong interface conversion
* remove import
---
 beacon-chain/sync/rpc_goodbye.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/beacon-chain/sync/rpc_goodbye.go b/beacon-chain/sync/rpc_goodbye.go
index cda906204..0a0c83892 100644
--- a/beacon-chain/sync/rpc_goodbye.go
+++ b/beacon-chain/sync/rpc_goodbye.go
@@ -27,7 +27,10 @@ func (r *Service) goodbyeRPCHandler(ctx context.Context, msg interface{}, stream
 	defer cancel()
 	setRPCStreamDeadlines(stream)
 
-	m := msg.(uint64)
+	m, ok:= msg.(uint64)
+	if !ok {
+		return fmt.Errorf("wrong message type for goodbye, got %T, wanted uint64", msg)
+	}
 	log := log.WithField("Reason", goodbyeMessage(m))
 	log.WithField("peer", stream.Conn().RemotePeer()).Info("Peer has sent a goodbye message")
 	// closes all streams with the peer