Catch unhandled exception (EADDRINUSE) in listeners (libp2p#128)

fix(transport): Catch unhandled errors (EADDRINUSE)

Author: haadcode

src/transport.js

@@ -80,7 +80,11 @@ module.exports = function (swarm) {
       const createListeners = multiaddrs.map((ma) => {
         return (cb) => {
           const listener = transport.createListener(handler)
+
+          listener.once('error', cb)
+
           listener.listen(ma, () => {
+            listener.removeListener('error', cb)
             listener.getAddrs((err, addrs) => {
               if (err) {
                 return cb(err)
@@ -93,7 +97,11 @@ module.exports = function (swarm) {
         }
       })
 
-      parallel(createListeners, () => {
+      parallel(createListeners, (err) => {
+        if (err) {
+          return callback(err)
+        }
+
         // cause we can listen on port 0 or 0.0.0.0
         swarm._peerInfo.multiaddr.replace(multiaddrs, freshMultiaddrs)
         callback()

test/01-transport-tcp.node.js

@@ -186,4 +186,27 @@ describe('transport - tcp', function () {
       swarm.close(done)
     }
   })
+
+  it('handles EADDRINUSE error when trying to listen', (done) => {
+    let swarm1, swarm2
+    swarm1 = new Swarm(peerA)
+    swarm1.transport.add('tcp', new TCP())
+    swarm1.transport.listen('tcp', {}, (conn) => {
+      pull(conn, conn)
+    }, () => {
+      // Add in-use (peerA) address to peerB
+      peerB.multiaddr.add(multiaddr('/ip4/127.0.0.1/tcp/9888'))
+      swarm2 = new Swarm(peerB)
+      swarm2.transport.add('tcp', new TCP())
+      swarm2.transport.listen('tcp', {}, (conn) => {
+        pull(conn, conn)
+      }, ready)
+    })
+
+    function ready (err) {
+      expect(err).to.exist
+      expect(err.code).to.equal('EADDRINUSE')
+      swarm1.close(() => swarm2.close(done))
+    }
+  })
 })