webpacker: Cannot deploy to staging or demo environments

We have a ‘staging’ environment set up in our webpacker.yml:

# Note: You must restart bin/webpack-dev-server for changes to take effect

default: &default
  source_path: app/javascript
  source_entry_path: packs
  public_output_path: packs
  cache_path: tmp/cache/webpacker

  # Additional paths webpack should lookup modules
  # ['app/assets', 'engine/foo/app/assets']
  resolved_paths: []

  # Reload manifest.json on all requests so we reload latest compiled packs
  cache_manifest: false

  extensions:
    - .coffee
    - .erb
    - .js
    - .jsx
    - .ts
    - .vue
    - .sass
    - .scss
    - .css
    - .png
    - .svg
    - .gif
    - .jpeg
    - .jpg

development:
  <<: *default
  compile: true

  # Reference: https://webpack.js.org/configuration/dev-server/
  dev_server:
    https: false
    host: localhost
    port: 3035
    public: localhost:3035
    hmr: false
    # Inline should be set to true if using HMR
    inline: true
    overlay: true
    disable_host_check: true
    use_local_ip: false

test:
  <<: *default
  compile: true

  # Compile test packs to a separate directory
  public_output_path: packs-test

production:
  <<: *default

  # Production depends on precompilation of packs prior to booting for performance.
  compile: false

  # Cache manifest.json for performance
  cache_manifest: true
  source_entry_path: pcl/packs
  public_output_path: pcl/packs

staging:
  <<: *default
  # Staging depends on precompilation of packs prior to booting for performance.
  compile: false
  # Cache manifest.json for performance
  cache_manifest: true
  source_entry_path: pcl/packs
  public_output_path: pcl/packs

node_modules/@rails/webpacker/lib/install/config/webpacker.yml does not have a staging environment defined.

We get the following error:

Compiling
Compilation failed:

/home/user/app/shared/node_modules/@rails/webpacker/package/config.js:15
delete defaultConfig.extensions
^

TypeError: Cannot convert undefined or null to object
at Object.<anonymous> (/home/user/app/shared/node_modules/@rails/webpacker/package/config.js:15:3)
at Module._compile (module.js:641:30)
at Object.Module._extensions..js (module.js:652:10)
at Module.load (module.js:560:32)
at tryModuleLoad (module.js:503:12)
at Function.Module._load (module.js:495:3)
at Module.require (module.js:585:17)
at require (internal/module.js:11:18)
at Object.<anonymous> (/home/user/app/shared/node_modules/@rails/webpacker/package/rules/babel.js:2:24)
at Module._compile (module.js:641:30)
rake stderr: Nothing written

delete defaultConfig.extensions is trying to delete keys in staging (because our own Webpacker config has a staging env defined), but is failing because the default file does not take into account staging environment.

Obviously adding staging won’t fix issues for others that have custom name environments.

This is an issue with 3.2.2.

Works fine in 3.2.1.