net: net.Server.listen() avoid operations on null when fail

When `net.Server` fails to create a new handle, an error shall be
emitted in the next tick. Therefore, we make `net.Server.listen()`
directly return to avoid following operations on `null`
`this._handle`.
Fixes: #23917
PR-URL: #23920
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>

Author: oyyd

lib/net.js

@@ -1435,6 +1435,13 @@ Server.prototype.listen = function(...args) {
 backlog=options.backlog||backlogFromArgs;
 listenInCluster(this,pipeName,-1,-1,
 backlog,undefined,options.exclusive);
+
+if(!this._handle){
+// Failed and an error shall be emitted in the next tick.
+// Therefore, we directly return.
+returnthis;
+}
+
 letmode=0;
 if(options.readableAll===true)
 mode|=PipeConstants.UV_READABLE;

test/parallel/test-net-server-listen-path.js

@@ -69,3 +69,23 @@ function randomPipePath() {
 srv.close();
 }));
 }
+
+// Test should emit "error" events when listening fails.
+{
+consthandlePath=randomPipePath();
+constsrv1=net.createServer().listen({path: handlePath},()=>{
+// As the handlePath is in use, binding to the same address again should
+// make the server emit an 'EADDRINUSE' error.
+constsrv2=net.createServer()
+.listen({
+path: handlePath,
+writableAll: true,
+},common.mustNotCall());
+
+srv2.on('error',common.mustCall((err)=>{
+srv1.close();
+assert.strictEqual(err.code,'EADDRINUSE');
+assert(/^listenEADDRINUSE:addressalreadyinuse/.test(err.message));
+}));
+});
+}