From 979f7334c295ccd527b57661c250118599eb654f Mon Sep 17 00:00:00 2001
From: Yuta Hiroto <git@about-hiroppy.com>
Date: Sat, 1 Jun 2019 01:56:25 +0200
Subject: [PATCH] fix(options): allow passing promise function of
 webpack.config.js

---
 lib/utils/processOptions.js                    | 14 ++++++++------
 test/cli.test.js                               | 12 ++++++++++++
 test/fixtures/promise-config/foo.js            |  3 +++
 test/fixtures/promise-config/webpack.config.js | 12 ++++++++++++
 test/helpers/test-bin.js                       | 13 ++++++++++---
 5 files changed, 45 insertions(+), 9 deletions(-)
 create mode 100644 test/fixtures/promise-config/foo.js
 create mode 100644 test/fixtures/promise-config/webpack.config.js

diff --git a/lib/utils/processOptions.js b/lib/utils/processOptions.js
index ee7138ac29..23da69b430 100644
--- a/lib/utils/processOptions.js
+++ b/lib/utils/processOptions.js
@@ -6,12 +6,14 @@ const defaultPort = require('./defaultPort');
 function processOptions(config, argv, callback) {
   // processOptions {Promise}
   if (typeof config.then === 'function') {
-    config.then(processOptions).catch((err) => {
-      // eslint-disable-next-line no-console
-      console.error(err.stack || err);
-      // eslint-disable-next-line no-process-exit
-      process.exit();
-    });
+    config
+      .then((conf) => processOptions(conf, argv, callback))
+      .catch((err) => {
+        // eslint-disable-next-line no-console
+        console.error(err.stack || err);
+        // eslint-disable-next-line no-process-exit
+        process.exit(1);
+      });
 
     return;
   }
diff --git a/test/cli.test.js b/test/cli.test.js
index 966e3e584d..7aec9caeaf 100644
--- a/test/cli.test.js
+++ b/test/cli.test.js
@@ -100,6 +100,18 @@ describe('CLI', () => {
       .catch(done);
   });
 
+  it('should accept the function of webpack.config.js', (done) => {
+    testBin(
+      false,
+      resolve(__dirname, './fixtures/promise-config/webpack.config.js')
+    )
+      .then((output) => {
+        expect(output.code).toEqual(0);
+        done();
+      })
+      .catch(done);
+  });
+
   it('should exit the process when SIGINT is detected', (done) => {
     const cliPath = resolve(__dirname, '../bin/webpack-dev-server.js');
     const examplePath = resolve(__dirname, '../examples/cli/public');
diff --git a/test/fixtures/promise-config/foo.js b/test/fixtures/promise-config/foo.js
new file mode 100644
index 0000000000..f88d8b5040
--- /dev/null
+++ b/test/fixtures/promise-config/foo.js
@@ -0,0 +1,3 @@
+'use strict';
+
+console.log('i am foo!');
diff --git a/test/fixtures/promise-config/webpack.config.js b/test/fixtures/promise-config/webpack.config.js
new file mode 100644
index 0000000000..9265f94362
--- /dev/null
+++ b/test/fixtures/promise-config/webpack.config.js
@@ -0,0 +1,12 @@
+'use strict';
+
+const { join } = require('path');
+
+module.exports = () => {
+  return new Promise((resolve) => {
+    resolve({
+      mode: 'development',
+      entry: join(__dirname, 'foo.js'),
+    });
+  });
+};
diff --git a/test/helpers/test-bin.js b/test/helpers/test-bin.js
index 2c7b5e98ae..83b506ee71 100644
--- a/test/helpers/test-bin.js
+++ b/test/helpers/test-bin.js
@@ -12,7 +12,7 @@ const basicConfigPath = path.resolve(
   '../fixtures/cli/webpack.config.js'
 );
 
-function runWebackDevServer(testArgs, configPath) {
+function testBin(testArgs, configPath) {
   const cwd = process.cwd();
   const env = process.env.NODE_ENV;
   let stdout = '';
@@ -36,7 +36,14 @@ function runWebackDevServer(testArgs, configPath) {
     child.on('error', (error) => reject(error));
 
     child.stdout.on('data', (data) => {
-      stdout += data.toString();
+      const str = data.toString();
+
+      stdout += str;
+
+      // if webpack.config.js is a promise function, it won't be able to call `close`
+      if (str.includes('Compiled successfully.')) {
+        child.kill();
+      }
     });
 
     child.stderr.on('data', (data) => {
@@ -52,4 +59,4 @@ function runWebackDevServer(testArgs, configPath) {
   });
 }
 
-module.exports = runWebackDevServer;
+module.exports = testBin;