From 45797757803cf51117417caf400d64f1d0cee2e7 Mon Sep 17 00:00:00 2001
From: Joe Bateson <joe@joebateson.com>
Date: Sat, 27 Jul 2019 04:46:00 -0700
Subject: [PATCH] fix: check for name of HotModuleReplacementPlugin to avoid
 RangeError (#2146)

---
 lib/utils/addEntries.js              |  5 +++--
 test/server/utils/addEntries.test.js | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/lib/utils/addEntries.js b/lib/utils/addEntries.js
index fb5e542e75..117bd9a835 100644
--- a/lib/utils/addEntries.js
+++ b/lib/utils/addEntries.js
@@ -93,8 +93,9 @@ function addEntries(config, options, server) {
         config.plugins = config.plugins || [];
         if (
           !config.plugins.find(
-            (plugin) =>
-              plugin.constructor === webpack.HotModuleReplacementPlugin
+            // Check for the name rather than the constructor reference in case
+            // there are multiple copies of webpack installed
+            (plugin) => plugin.constructor.name === 'HotModuleReplacementPlugin'
           )
         ) {
           config.plugins.push(new webpack.HotModuleReplacementPlugin());
diff --git a/test/server/utils/addEntries.test.js b/test/server/utils/addEntries.test.js
index 608bd61a30..1bc6a6cef6 100644
--- a/test/server/utils/addEntries.test.js
+++ b/test/server/utils/addEntries.test.js
@@ -246,6 +246,26 @@ describe('addEntries util', () => {
     ]);
   });
 
+  it("should not add the HMR plugin again if it's already there from a different webpack", () => {
+    const existingPlugin = new webpack.BannerPlugin('bruce');
+
+    // Simulate the inclusion of another webpack's HotModuleReplacementPlugin
+    class HotModuleReplacementPlugin {}
+
+    const webpackOptions = Object.assign({}, config, {
+      plugins: [new HotModuleReplacementPlugin(), existingPlugin],
+    });
+    const devServerOptions = { hot: true };
+
+    addEntries(webpackOptions, devServerOptions);
+
+    expect(webpackOptions.plugins).toEqual([
+      // Nothing should be injected
+      new HotModuleReplacementPlugin(),
+      existingPlugin,
+    ]);
+  });
+
   it('should can prevent duplicate entries from successive calls', () => {
     const webpackOptions = Object.assign({}, config);
     const devServerOptions = { hot: true };