fixes #860: failure to exit on SIGINT race condition

bin/webpack-dev-server.js

@@ -390,8 +390,9 @@ function startDevServer(webpackOptions, options) {
 
   ['SIGINT', 'SIGTERM'].forEach((sig) => {
     process.on(sig, () => {
-      server.close();
-      process.exit(); // eslint-disable-line no-process-exit
+      server.close(() => {
+        process.exit(); // eslint-disable-line no-process-exit
+      });
     });
   });
 

package.json

@@ -73,6 +73,7 @@
     "eslint": "^4.5.0",
     "eslint-config-webpack": "^1.2.5",
     "eslint-plugin-import": "^2.7.0",
+    "execa": "^0.8.0",
     "file-loader": "^0.11.2",
     "istanbul": "^0.4.5",
     "jquery": "^3.2.1",

test/cli.test.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const assert = require('assert');
+const path = require('path');
+const execa = require('execa');
+
+describe('SIGINT', () => {
+  it('without filename option it should throw an error', (done) => {
+    const cliPath = path.resolve(__dirname, '../bin/webpack-dev-server.js');
+    const examplePath = path.resolve(__dirname, '../examples/cli-public');
+    const nodePath = execa.shellSync('which node').stdout;
+
+    const proc = execa(nodePath, [cliPath], { cwd: examplePath });
+
+    proc.stdout.on('data', (data) => {
+      const bits = data.toString();
+
+      if (/webpack: Compiled successfully/.test(bits)) {
+        assert(proc.pid !== 0);
+        proc.kill('SIGINT');
+      }
+    });
+
+    proc.on('exit', () => {
+      done();
+    });
+  });
+});