delete defaultConfig.extensions: Cannot convert undefined or null to object

[doits]

I've a custom env called staging. Therefore my webpacker.yml has this entry:

...

production: &production
  ...

staging:
  <<: *production

And I have this symlink:

config/webpack/staging.js --> config/webpack/production.js

Before 3.2.2, everything was fine on staging. Now I get this on compile:

Webpacker is installed 🎉 🍰
Using /var/www/events/demo-a_staging/releases/20180214180938/config/webpacker.yml file for setting up webpack paths
Compiling…
Compilation failed:

/var/www/events/demo-a_staging/shared/node_modules/@rails/webpacker/package/config.js:15
  delete defaultConfig.extensions
  ^

TypeError: Cannot convert undefined or null to object
    at Object.<anonymous> (/var/www/events/demo-a_staging/shared/node_modules/@rails/webpacker/package/config.js:15:3)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Module.require (module.js:587:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/var/www/events/demo-a_staging/shared/node_modules/@rails/webpacker/package/rules/babel.js:2:24)
    at Module._compile (module.js:643:30)

On development everything works.

Looks like something broke custom envs? defaultConfig is null?

[doits]

oops, just saw #1265, you're already working on it 👍

[gauravtiwari]

Please use 3.3.0

[doits]

This is still happening for me in 3.3.0

[Systho]

related to #1274