http: use listenerCount when adding noop event

PR-URL: #46769
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: ShogunPanda

lib/_http_server.js

@@ -813,10 +813,29 @@ const requestHeaderFieldsTooLargeResponse = Buffer.from(
 `HTTP/1.1 431 ${STATUS_CODES[431]}\r\n`+
 'Connection: close\r\n\r\n','ascii',
 );
+
+functionwarnUnclosedSocket(){
+if(warnUnclosedSocket.emitted){
+return;
+}
+
+warnUnclosedSocket.emitted=true;
+process.emitWarning(
+'An error event has already been emitted on the socket. '+
+'Please use the destroy method on the socket while handling '+
+"a 'clientError' event.",
+);
+}
+
 functionsocketOnError(e){
 // Ignore further errors
 this.removeListener('error',socketOnError);
-this.on('error',noop);
+
+if(this.listenerCount('error',noop)===0){
+this.on('error',noop);
+}else{
+warnUnclosedSocket();
+}
 
 if(!this.server.emit('clientError',e,this)){
 // Caution must be taken to avoid corrupting the remote peer.

test/parallel/test-http-socket-error-listeners.js

@@ -0,0 +1,47 @@
+// Flags: --no-warnings
+
+'use strict';
+
+constcommon=require('../common');
+constassert=require('assert');
+consthttp=require('http');
+constnet=require('net');
+
+// This test sends an invalid character to a HTTP server and purposely
+// does not handle clientError (even if it sets an event handler).
+//
+// The idea is to let the server emit multiple errors on the socket,
+// mostly due to parsing error, and make sure they don't result
+// in leaking event listeners.
+
+{
+leti=0;
+letsocket;
+process.on('warning',common.mustCall());
+
+constserver=http.createServer(common.mustNotCall());
+
+server.on('clientError',common.mustCallAtLeast((err)=>{
+assert.strictEqual(err.code,'HPE_INVALID_METHOD');
+assert.strictEqual(err.rawPacket.toString(),'*');
+
+if(i===20){
+socket.end();
+}else{
+socket.write('*');
+i++;
+}
+},1));
+
+server.listen(0,()=>{
+socket=net.createConnection({port: server.address().port});
+
+socket.on('connect',()=>{
+socket.write('*');
+});
+
+socket.on('close',()=>{
+server.close();
+});
+});
+}