fix: do not use while loop for quic transport errors (#1317)

libp2p/transports/quictransport.nim

@@ -255,7 +255,7 @@ method stop*(transport: QuicTransport) {.async: (raises: []).} =
 
 proc wrapConnection(
     transport: QuicTransport, connection: QuicConnection
-): QuicSession {.raises: [TransportOsError, LPError].} =
+): QuicSession {.raises: [TransportOsError, MaError].} =
   let
     remoteAddr = connection.remoteAddress()
     observedAddr =
@@ -283,22 +283,23 @@ method accept*(
 .} =
   doAssert not self.listener.isNil, "call start() before calling accept()"
 
-  while true:
-    if not self.running:
-      # stop accept only when transport is stopped (not when error occurs)
-      raise newException(QuicTransportAcceptStopped, "Quic transport stopped")
+  if not self.running:
+    # stop accept only when transport is stopped (not when error occurs)
+    raise newException(QuicTransportAcceptStopped, "Quic transport stopped")
 
-    try:
-      let connection = await self.listener.accept()
-      return self.wrapConnection(connection)
-    except CancelledError as e:
-      raise e
-    except QuicError as e:
-      trace "Quic accept connection error", msg = e.msg
-      # swallow all errors and continue accepting until connection is established
-      continue
-    except CatchableError as e:
-      raise (ref QuicTransportError)(msg: e.msg, parent: e)
+  try:
+    let connection = await self.listener.accept()
+    return self.wrapConnection(connection)
+  except CancelledError as exc:
+    raise exc
+  except QuicError as exc:
+    debug "Quic Error", description = exc.msg
+  except MaError as exc:
+    debug "Multiaddr Error", description = exc.msg
+  except CatchableError as exc: # TODO: removing this requires async/raises in nim-quic
+    info "Unexpected error accepting quic connection", description = exc.msg
+  except TransportOsError as exc:
+    debug "OS Error", description = exc.msg
 
 method dial*(
     self: QuicTransport,

tests/testquic.nim

@@ -24,6 +24,9 @@ proc createServerAcceptConn(
   .} =
     try:
       let conn = await server.accept()
+      if conn == nil:
+        return
+
       let stream = await getStream(QuicSession(conn), Direction.In)
       var resp: array[6, byte]
       await stream.readExactly(addr resp, 6)