fix: do not swallow errors from server (#2512)

Author: EslamHiko

lib/Server.js

@@ -687,6 +687,10 @@ class Server {
  } else {
  this.listeningApp = http.createServer(this.app);
  }
+
+ this.listeningApp.on('error', (err) => {
+ this.log.error(err);
+ });
  }
 
  createSocketServer() {

test/server/Server.test.js

@@ -76,6 +76,16 @@ describe('Server', () => {
  });
  });
 
+ it('test listeningApp error reporting', () => {
+ const logMock = jest.fn();
+ const compiler = webpack(config);
+ const server = new Server(compiler, baseDevConfig);
+
+ server.log.error = logMock;
+
+ server.listeningApp.emit('error', new Error('Error !!!'));
+ expect(server.log.error).toBeCalledWith(new Error('Error !!!'));
+ });
  // issue: https://github.com/webpack/webpack-dev-server/issues/1724
  describe('express.static.mine.types', () => {
  it("should success even if mine.types doesn't exist", (done) => {