fix: WebRTC uncaught promise rejection on incoming connection (#2302)

We catch WebRTC errors, log them and throw normalised errors to ensure they are the same across WebRTC stacks (FF, Chrome, node).

#2299 made one of these operations async which would cause an UHPR if thrown.

Author: achingbrain

packages/transport-webrtc/src/private-to-private/initiate-connection.ts

@@ -96,7 +96,10 @@ export async function initiateConnection ({ peerConnection, signal, metrics, mul
       }
 
       // create an offer
-      const offerSdp = await peerConnection.createOffer()
+      const offerSdp = await peerConnection.createOffer().catch(err => {
+        log.error('could not execute createOffer', err)
+        throw new CodeError('Failed to set createOffer', 'ERR_SDP_HANDSHAKE_FAILED')
+      })
 
       log.trace('initiator send SDP offer %s', offerSdp.sdp)
 
@@ -117,7 +120,7 @@ export async function initiateConnection ({ peerConnection, signal, metrics, mul
       })
 
       if (answerMessage.type !== Message.Type.SDP_ANSWER) {
-        throw new CodeError('remote should send an SDP answer', 'ERR_SDP_HANDSHAKE_FAILED')
+        throw new CodeError('Remote should send an SDP answer', 'ERR_SDP_HANDSHAKE_FAILED')
       }
 
       log.trace('initiator receive SDP answer %s', answerMessage.data)

packages/transport-webrtc/src/private-to-private/signaling-stream-handler.ts

@@ -1,7 +1,6 @@
 import { CodeError } from '@libp2p/interface'
 import { multiaddr, type Multiaddr } from '@multiformats/multiaddr'
 import { pbStream } from 'it-protobuf-stream'
-import pDefer, { type DeferredPromise } from 'p-defer'
 import { type RTCPeerConnection, RTCSessionDescription } from '../webrtc/index.js'
 import { Message } from './pb/message.js'
 import { readCandidatesUntilConnected } from './util.js'
@@ -20,8 +19,6 @@ export async function handleIncomingStream ({ peerConnection, stream, signal, co
   const messageStream = pbStream(stream).pb(Message)
 
   try {
-    const answerSentPromise: DeferredPromise<void> = pDefer()
-
     // candidate callbacks
     peerConnection.onicecandidate = ({ candidate }) => {
       // a null candidate means end-of-candidates, an empty string candidate
@@ -67,7 +64,6 @@ export async function handleIncomingStream ({ peerConnection, stream, signal, co
     // create and write an SDP answer
     const answer = await peerConnection.createAnswer().catch(err => {
       log.error('could not execute createAnswer', err)
-      answerSentPromise.reject(err)
       throw new CodeError('Failed to create answer', 'ERR_SDP_HANDSHAKE_FAILED')
     })
 
@@ -78,16 +74,11 @@ export async function handleIncomingStream ({ peerConnection, stream, signal, co
       signal
     })
 
-    peerConnection.setLocalDescription(answer).then(() => {
-      answerSentPromise.resolve()
-    }, err => {
+    await peerConnection.setLocalDescription(answer).catch(err => {
       log.error('could not execute setLocalDescription', err)
-      answerSentPromise.reject(err)
       throw new CodeError('Failed to set localDescription', 'ERR_SDP_HANDSHAKE_FAILED')
     })
 
-    await answerSentPromise.promise
-
     log.trace('recipient read candidates until connected')
 
     // wait until candidates are connected
@@ -96,11 +87,6 @@ export async function handleIncomingStream ({ peerConnection, stream, signal, co
       signal,
       log
     })
-
-    log.trace('recipient connected, closing signaling stream')
-    await messageStream.unwrap().unwrap().close({
-      signal
-    })
   } catch (err: any) {
     if (peerConnection.connectionState !== 'connected') {
       log.error('error while handling signaling stream from peer %a', connection.remoteAddr, err)

packages/transport-webrtc/test/peer.spec.ts

@@ -214,7 +214,7 @@ describe('webrtc dialer', () => {
     const answer = await pc.createAnswer()
     await pc.setLocalDescription(answer)
 
-    await expect(initiatorPeerConnectionPromise).to.be.rejectedWith(/remote should send an SDP answer/)
+    await expect(initiatorPeerConnectionPromise).to.be.rejectedWith(/Remote should send an SDP answer/)
 
     pc.close()
   })