title: “webpack binstubs not found.” on Heroku
body: <p>I’ve spun up a new rails project with the following command: rails new  -d postgresql --skip-spring --skip-test --webpack=react</p>
  <p>Following this, I created my database, added &lt;%= javascript_pack_tag 'hello_react' %&gt; to application.html.erb and generated a homepage.</p>
  <p>I then ran:</p>
  <p>rails s # tab 1
  bin/webpack-dev-server # tab 2
  This all works fine and I can see “Hello World!” at localhost:3000.</p>
  <p>However, when I try to push to Heroku, the build fails at webpack binstubs not found.. I can confirm that bin/webpack does exist, doing rails webpack:install:react does nothing.</p>
  <p>I’ve followed the instructions at webpacker/deployment.md at master · rails/webpacker · GitHub to no avail, still getting the exact same error. I’ve even tried setting compile: true in config/webpacker.yml, in the production section. Nothing.</p>
  <p>This seems odd as this is a new project with nothing special in it; I’m confused as to why it cannot seem to find the declaration of bin/webpack. It is not in my .gitignore.</p>
  <p>Any help would be great.</p>
  <p>Cheers.</p>
  <p>Full build log:</p>
  <pre><code>-----&gt; Node.js app detected
         
  -----&gt; Creating runtime environment
         
         NPM_CONFIG_LOGLEVEL=error
         USE_YARN_CACHE=true
         NODE_ENV=production
         NODE_MODULES_CACHE=true
         NODE_VERBOSE=false
         
  -----&gt; Installing binaries
         engines.node (package.json):  unspecified
         engines.npm (package.json):   unspecified (use default)
         engines.yarn (package.json):  unspecified (use default)
         
         Resolving node version 12.x...
         Downloading and installing node 12.19.1...
         Using default npm version: 6.14.8
         Resolving yarn version 1.22.x...
         Downloading and installing yarn (1.22.10)
         Installed yarn 1.22.10
         
  -----&gt; Installing dependencies
         Installing node modules (yarn.lock)
         yarn install v1.22.10
         [1/4] Resolving packages...
         [2/4] Fetching packages...
         info fsevents@2.1.3: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@2.1.3&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         info fsevents@1.2.13: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@1.2.13&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         [3/4] Linking dependencies...
         warning &quot; &gt; @babel/preset-react@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-display-name@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-development@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-self@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-source@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-pure-annotations@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx &gt; @babel/plugin-syntax-jsx@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot; &gt; webpack-dev-server@3.11.0&quot; has unmet peer dependency &quot;webpack@^4.0.0 || ^5.0.0&quot;.
         warning &quot;webpack-dev-server &gt; webpack-dev-middleware@3.7.2&quot; has unmet peer dependency &quot;webpack@^4.0.0&quot;.
         [4/4] Building fresh packages...
         Done in 29.74s.
         
  -----&gt; Build
         
  -----&gt; Pruning devDependencies
         yarn install v1.22.10
         [1/4] Resolving packages...
         [2/4] Fetching packages...
         info fsevents@2.1.3: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@2.1.3&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         info fsevents@1.2.13: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@1.2.13&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         [3/4] Linking dependencies...
         warning &quot; &gt; @babel/preset-react@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-display-name@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-development@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-self@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-source@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-pure-annotations@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx &gt; @babel/plugin-syntax-jsx@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot; &gt; webpack-dev-server@3.11.0&quot; has unmet peer dependency &quot;webpack@^4.0.0 || ^5.0.0&quot;.
         warning &quot;webpack-dev-server &gt; webpack-dev-middleware@3.7.2&quot; has unmet peer dependency &quot;webpack@^4.0.0&quot;.
         [4/4] Building fresh packages...
         warning Ignored scripts due to flag.
         Done in 5.82s.
         
  -----&gt; Caching build
         - yarn cache
         
  -----&gt; Build succeeded!
   !     This app may not specify any way to start a node process
         https://devcenter.heroku.com/articles/nodejs-support#default-web-process-type
   !     Unmet dependencies don't fail yarn install but may cause runtime issues
         https://github.com/npm/npm/issues/7494
  -----&gt; Ruby app detected
  -----&gt; Installing bundler 2.1.4
  -----&gt; Removing BUNDLED WITH version in the Gemfile.lock
  -----&gt; Compiling Ruby/Rails
  -----&gt; Using Ruby version: ruby-2.7.2
  -----&gt; Installing dependencies using bundler 2.1.4
         Running: BUNDLE_WITHOUT='development:test' BUNDLE_PATH=vendor/bundle BUNDLE_BIN=vendor/bundle/bin BUNDLE_DEPLOYMENT=1 bundle install -j4
         The dependency tzinfo-data (&gt;= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
         Fetching gem metadata from https://rubygems.org/............
         Fetching rake 13.0.1
         Installing rake 13.0.1
         Fetching concurrent-ruby 1.1.7
         Fetching thread_safe 0.3.6
         Fetching minitest 5.14.2
         Installing thread_safe 0.3.6
         Installing minitest 5.14.2
         Installing concurrent-ruby 1.1.7
         Fetching zeitwerk 2.4.1
         Installing zeitwerk 2.4.1
         Fetching builder 3.2.4
         Fetching erubi 1.10.0
         Installing builder 3.2.4
         Installing erubi 1.10.0
         Fetching mini_portile2 2.4.0
         Fetching crass 1.0.6
         Installing mini_portile2 2.4.0
         Installing crass 1.0.6
         Fetching rack 2.2.3
         Installing rack 2.2.3
         Fetching nio4r 2.5.4
         Installing nio4r 2.5.4 with native extensions
         Fetching websocket-extensions 0.1.5
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         Fetching mimemagic 0.3.5
         Fetching mini_mime 1.0.2
         Installing mini_mime 1.0.2
         Installing mimemagic 0.3.5
         Fetching msgpack 1.3.3
         Installing msgpack 1.3.3 with native extensions
         Using bundler 2.1.4
         Fetching ffi 1.13.1
         Installing ffi 1.13.1 with native extensions
         Fetching method_source 1.0.0
         Installing method_source 1.0.0
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         Fetching thor 1.0.1
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         Fetching tilt 2.0.10
         Installing tilt 2.0.10
         Fetching turbolinks-source 5.2.0
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         Fetching tzinfo 1.2.8
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         Installing nokogiri 1.10.10 with native extensions
         Fetching i18n 1.8.5
         Installing i18n 1.8.5
         Fetching rack-test 1.1.0
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         Fetching rack-proxy 0.6.5
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         Fetching sprockets 4.0.2
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         Fetching websocket-driver 0.7.3
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         Fetching mail 2.7.1
         Installing mail 2.7.1
         Fetching marcel 0.3.3
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         Fetching puma 4.3.6
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         Fetching activesupport 6.0.3.4
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         Fetching rails 6.0.3.4
         Fetching webpacker 4.3.0
         Installing rails 6.0.3.4
         Installing webpacker 4.3.0
         Fetching sassc-rails 2.1.2
         Installing sassc-rails 2.1.2
         Fetching sass-rails 6.0.0
         Installing sass-rails 6.0.0
         Bundle complete! 12 Gemfile dependencies, 57 gems now installed.
         Gems in the groups development and test were not installed.
         Bundled gems are installed into `./vendor/bundle`
         Post-install message from i18n:
         
         HEADS UP! i18n 1.1 changed fallbacks to exclude default locale.
         But that may break your application.
         
         If you are upgrading your Rails application from an older version of Rails:
         
         Please check your Rails app for 'config.i18n.fallbacks = true'.
         If you're using I18n (&gt;= 1.1.0) and Rails (&lt; 5.2.2), this should be
         'config.i18n.fallbacks = [I18n.default_locale]'.
         If not, fallbacks will be broken in your app by I18n 1.1.x.
         
         If you are starting a NEW Rails application, you can ignore this notice.
         
         For more info see:
         https://github.com/svenfuchs/i18n/releases/tag/v1.1.0
         
         Bundle completed (208.33s)
         Cleaning up the bundler cache.
  -----&gt; Detecting rake tasks
  -----&gt; Preparing app for Rails asset pipeline
         Running: rake assets:precompile
         yarn install v1.22.10
         [1/4] Resolving packages...
         [2/4] Fetching packages...
         info fsevents@2.1.3: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@2.1.3&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         info fsevents@1.2.13: The platform &quot;linux&quot; is incompatible with this module.
         info &quot;fsevents@1.2.13&quot; is an optional dependency and failed compatibility check. Excluding it from installation.
         [3/4] Linking dependencies...
         warning &quot; &gt; @babel/preset-react@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-display-name@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-development@7.12.7&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-self@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx-source@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-pure-annotations@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot;@babel/preset-react &gt; @babel/plugin-transform-react-jsx &gt; @babel/plugin-syntax-jsx@7.12.1&quot; has unmet peer dependency &quot;@babel/core@^7.0.0-0&quot;.
         warning &quot; &gt; webpack-dev-server@3.11.0&quot; has unmet peer dependency &quot;webpack@^4.0.0 || ^5.0.0&quot;.
         warning &quot;webpack-dev-server &gt; webpack-dev-middleware@3.7.2&quot; has unmet peer dependency &quot;webpack@^4.0.0&quot;.
         [4/4] Building fresh packages...
         Done in 29.50s.
         I, [2020-11-25T12:02:13.452090 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/manifest-b4bf6e57a53c2bdb55b8998cc94cd00883793c1c37c5e5aea3ef6749b4f6d92b.js
         I, [2020-11-25T12:02:13.452388 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/manifest-b4bf6e57a53c2bdb55b8998cc94cd00883793c1c37c5e5aea3ef6749b4f6d92b.js.gz
         I, [2020-11-25T12:02:13.452661 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/application-04024382391bb910584145d8113cf35ef376b55d125bb4516cebeb14ce788597.css
         I, [2020-11-25T12:02:13.452831 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/application-04024382391bb910584145d8113cf35ef376b55d125bb4516cebeb14ce788597.css.gz
         I, [2020-11-25T12:02:13.453156 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/home-04024382391bb910584145d8113cf35ef376b55d125bb4516cebeb14ce788597.css
         I, [2020-11-25T12:02:13.453335 #3686]  INFO -- : Writing /tmp/build_6728f1b1/public/assets/home-04024382391bb910584145d8113cf35ef376b55d125bb4516cebeb14ce788597.css.gz
         webpack binstubs not found.
         Have you run rails webpacker:install ?
         Make sure the bin directory or binstubs are not included in .gitignore
         Exiting!
   !
   !     Precompiling assets failed.
   !
   !     Push rejected, failed to compile Ruby app.
   !     Push failed
  </code></pre>