Webpacker 6: missing overlay errors (solved in webpack-dev-server 4)

[tagliala]

edit: should be caused by webpack/webpack-dev-server#2786 and fixed in webpack-dev-server v4

edit2: I can confirm that with the main branch of webpack-dev-server and some edits to development.js, overlay errors are back

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Hi,

I don't know if this is an issue with webpacker itself. With webpacker 5, I was able to see lint errors on the front-end, now I just get "failed to compile" error

How to replicate

1. Create application

$ rails _6.1.3_ new test-webpacker6-webpack-dev-server --skip-active-record --skip-javascript
$ cd test-webpacker6-webpack-dev-server
$ echo "gem 'webpacker', git: 'https://github.com/rails/webpacker.git'" >> Gemfile
$ bundle
$ rails webpacker:install
$ sed -i '3i\ \ root "pages#home"' config/routes.rb
$ sed -i '10i\ \ \ \ <%= javascript_pack_tag "application" %>' app/views/layouts/application.html.erb
$ rails g controller Pages home

2. Launch bin/webpack-dev-server
3. Launch the server rails s and navigate to http://localhost:3000/
4. Save application.js to check that hot reload works ("Hello World from Webpacker" appears in the console)
5. Make a syntax error in application.js
6. Save application.js

Before (Webpacker 5)

After (Webpacker 6)

I can still see errors in webpack-dev-server console

Ref: #2994

[dhh]

Upgraded to webpack-dev-server 4.