Raise defect for missing transports or addresses

libp2p/builders.nim

@@ -136,7 +136,7 @@ proc withNameResolver*(b: SwitchBuilder, nameResolver: NameResolver): SwitchBuil
   b
 
 proc build*(b: SwitchBuilder): Switch
-  {.raises: [Defect, LPError].} =
+  {.raises: [Defect, LPDefect, LPError].} =
 
   if b.rng == nil: # newRng could fail
     raise newException(Defect, "Cannot initialize RNG")
@@ -210,7 +210,7 @@ proc newStandardSwitch*(
   maxOut = -1,
   maxConnsPerPeer = MaxConnectionsPerPeer,
   nameResolver: NameResolver = nil): Switch
-  {.raises: [Defect, LPError].} =
+  {.raises: [Defect, LPDefect, LPError].} =
   if SecureProtocol.Secio in secureManagers:
       quit("Secio is deprecated!") # use of secio is unsafe
 

libp2p/errors.nim

@@ -9,6 +9,8 @@ type
   # Base exception type for libp2p
   LPError* = object of CatchableError
 
+  LPDefect* = object of CatchableError
+
 func toException*(e: cstring): ref LPError =
   (ref LPError)(msg: $e)
 

libp2p/switch.nim

@@ -261,7 +261,13 @@ proc newSwitch*(peerInfo: PeerInfo,
                 connManager: ConnManager,
                 ms: MultistreamSelect,
                 nameResolver: NameResolver = nil): Switch
-                {.raises: [Defect, LPError].} =
+                {.raises: [Defect, LPDefect, LPError].} =
+
+  if transports.len == 0:
+    raise newException(LPDefect, "Provide at least one transport")
+
+  if peerInfo.addrs.len == 0:
+    raise newException(LPDefect, "Provide at least one address")
 
   if secureManagers.len == 0:
     raise newException(LPError, "Provide at least one secure manager")

libp2p/transports/transport.nim

@@ -21,6 +21,7 @@ logScope:
   topics = "libp2p transport"
 
 type
+  TransportDefect* = object of Defect
   ListenErrorCallback* = proc (
       ma: MultiAddress,
       err: ref CatchableError): Future[ref TransportListenError]
@@ -56,11 +57,16 @@ const ListenErrorDefault* =
 
 method start*(
   self: Transport,
-  addrs: seq[MultiAddress]) {.base, async, raises: [Defect, TransportListenError].} =
+  addrs: seq[MultiAddress])
+  {.base, async, raises: [Defect, TransportDefect, TransportListenError].} =
   ## start the transport
   ##
 
   trace "starting transport on addrs", address = $addrs
+  if addrs.len == 0:
+    raise newException(TransportDefect,
+      "Transport requires at least one address to be started")
+
   self.addrs = addrs
   self.running = true
 

tests/testswitch.nim

@@ -1,6 +1,6 @@
 {.used.}
 
-import options, sequtils, sets, tables
+import options, sequtils, sets, sugar, tables
 import chronos
 import stew/byteutils
 import nimcrypto/sysrand
@@ -17,6 +17,7 @@ import ../libp2p/[errors,
                   protocols/secure/secure,
                   muxers/muxer,
                   muxers/mplex/lpchannel,
+                  muxers/mplex/mplex,
                   stream/lpstream,
                   nameresolving/nameresolver,
                   nameresolving/mockresolver,
@@ -1492,3 +1493,60 @@ suite "Switch":
     check switch.transports[0].addrs == @[maTcp1, maUdp, maTcp2]
 
     await switch.stop()
+
+  asyncTest "should raise defect if no transports provided during construction":
+    let
+      mAddrs = buildLocalTcpAddrs(3)
+      transport = (upgr: Upgrade) -> Transport => MockTransport.new(upgr)
+
+    # builder should raise defect with addresses, but no transports
+    expect LPDefect:
+      discard SwitchBuilder
+        .new()
+        .withRng(rng)       # Give the application RNG
+        .withAddresses(mAddrs)    # Our local address(es)
+        .withMplex()        # Use Mplex as muxer
+        .withNoise()        # Use Noise as secure manager
+        .build()
+
+    # builder should raise defect with transports, but no addresses
+    expect LPDefect:
+      echo "[testswitch] building switch with no addresses"
+      discard SwitchBuilder
+        .new()
+        .withRng(rng)       # Give the application RNG
+        .withTransport(transport)
+        .withAddresses(@[])
+        .withMplex()        # Use Mplex as muxer
+        .withNoise()        # Use Noise as secure manager
+        .build()
+
+    # should raise defect with addresses, but no transports
+    var
+      seckey = PrivateKey.random(rng[]).get()
+      peerInfo = PeerInfo.new(seckey, mAddrs)
+      identify = Identify.new(peerInfo)
+      muxers = initTable[string, MuxerProvider]()
+
+    muxers[MplexCodec] =
+       MuxerProvider.new((conn: Connection) -> Muxer => Mplex.new(conn), MplexCodec)
+
+    expect LPDefect:
+      discard newSwitch(
+        peerInfo = peerInfo,
+        transports = @[],
+        identity = identify,
+        muxers = muxers,
+        connManager = ConnManager.new(),
+        ms = MultistreamSelect.new())
+
+    # should raise defect with transports, but no addresses
+    peerInfo.addrs = @[]
+    expect LPDefect:
+      discard newSwitch(
+        peerInfo = peerInfo,
+        transports = @[transport(Upgrade.new())],
+        identity = identify,
+        muxers = muxers,
+        connManager = ConnManager.new(),
+        ms = MultistreamSelect.new())

tests/testtcptransport.nim

@@ -250,6 +250,14 @@ suite "TCP transport":
 
     await transport.stop()
 
+  asyncTest "should raise Defect on start with no addresses":
+    let transport = TcpTransport.new(upgrade = Upgrade())
+
+    expect TransportDefect:
+      await transport.start(@[])
+
+    await transport.stop()
+
   commonTransportTest(
     "TcpTransport",
     proc (): Transport = TcpTransport.new(upgrade = Upgrade()),

tests/testwstransport.nim

@@ -180,6 +180,14 @@ suite "WebSocket transport":
 
     await transport.stop()
 
+  asyncTest "should raise Defect on start with no addresses":
+    let transport = WsTransport.new(upgrade = Upgrade())
+
+    expect TransportDefect:
+      await transport.start(@[])
+
+    await transport.stop()
+
   commonTransportTest(
     "WebSocket",
     proc (): Transport = WsTransport.new(Upgrade()),