bug #939 fixing 2 issues related to webpack-dev-server and HMR (weaverryan)

This PR was squashed before being merged into the main branch.

Discussion
----------

fixing 2 issues related to webpack-dev-server and HMR

Fixes #931

* `liveReload` currently causes the page to ALWAYS reload: HMR never has a chance to update the content. Disabling by default. This will mean people that currently like the liveReload won't have it anymore unless they re-enable it. But allowing HMR to be broken is not ok. See: #931 (comment)

* The hostname used for the web socket changed in Webpack 4. For most users it doesn't matter... they use localhost everywhere. But this PR explicitly sets the web socket hostname to the hostname of the dev-server.

TODO: fix/add tests

Cheers!

Commits
-------

ed41a52 making test more fault tolerant
4178f64 fixing 2 issues related to webpack-dev-server and HMR - fixes #931

Author: weaverryan

lib/config-generator.js

@@ -597,6 +597,16 @@ class ConfigGenerator {
             headers: { 'Access-Control-Allow-Origin': '*' },
             compress: true,
             historyApiFallback: true,
+            // In webpack-dev-server v4 beta 0, liveReload always causes
+            // the page to refresh, not allowing HMR to update the page.
+            // This is somehow related to the "static" option, but it's
+            // unknown if there is a better option.
+            // See https://github.com/webpack/webpack-dev-server/issues/2893
+            liveReload: false,
+            client: {
+                // see https://github.com/symfony/webpack-encore/issues/931#issuecomment-784483725
+                host: this.webpackConfig.runtimeConfig.devServerHost,
+            }
         };
 
         return applyOptionsCallback(

test/functional.js

@@ -2212,11 +2212,11 @@ module.exports = {
                 testSetup.runWebpack(config, (webpackAssert) => {
                     webpackAssert.assertDirectoryContents([
                         'entrypoints.json',
-                        'runtime.fbc90386.js',
-                        'main.06a6c20f.js',
+                        'runtime.[hash:8].js',
+                        'main.[hash:8].js',
                         'manifest.json',
-                        'symfony_logo.91beba37.png',
-                        'symfony_logo_alt.f880ba14.png',
+                        'symfony_logo.[hash:8].png',
+                        'symfony_logo_alt.[hash:8].png',
                     ]);
 
                     webpackAssert.assertManifestPath(