From 4faf35c52c0987277eb5e8fec2965b1127e5f9e6 Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Wed, 12 Feb 2020 09:40:15 -0500
Subject: [PATCH] throw exception if handshake failed

---
 libp2p/multistream.nim | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/libp2p/multistream.nim b/libp2p/multistream.nim
index c8b2ff6..a03ee0e 100644
--- a/libp2p/multistream.nim
+++ b/libp2p/multistream.nim
@@ -38,6 +38,12 @@ type
     na: string
     ls: string
 
+  MultistreamHandshakeException* = object of CatchableError
+
+proc newMultistreamHandshakeException*(): ref Exception {.inline.} =
+  result = newException(MultistreamHandshakeException,
+    "could not perform multistream handshake")
+
 proc newMultistream*(): MultistreamSelect =
   new result
   result.codec = MSCodec
@@ -58,8 +64,8 @@ proc select*(m: MultistreamSelect,
   result = cast[string]((await conn.readLp())) # read ms header
   result.removeSuffix("\n")
   if result != Codec:
-    trace "handshake failed", codec = result.toHex()
-    return ""
+    error "handshake failed", codec = result.toHex()
+    raise newMultistreamHandshakeException()
 
   if proto.len() == 0: # no protocols, must be a handshake call
     return