webpack-overlay-bug

Simple app to reproduce webpack/webpack-dev-server#1042

This simple app was based on Webpack's Hot Module Replacement Guide

To reproduce the bug:

1. Install repo

git clone https://github.com/gcangussu/webpack-overlay-bug.git
cd webpack-overlay-bug
npm install

2. Start the app and open your browser console

npm start

You should see some performance warnings in the console like these:

[WDS] Warnings while compiling.
warnings @ main.js:4520
main.js:4526 asset size limit: The following asset(s) exceed the recommended size limit (250 kB).
This can impact web performance.
Assets: 
  main.js (355 kB)
warnings @ main.js:4526
main.js:4526 entrypoint size limit: The following entrypoint(s) combined asset size exceeds the recommended 
limit (250 kB). This can impact web performance.
Entrypoints:
  main (355 kB)
      main.js

warnings @ main.js:4526
main.js:4526 webpack performance recommendations: 
You can limit the size of your bundles by using import() or require.ensure to lazy load some parts of your application.
For more info visit https://webpack.js.org/guides/code-splitting/
warnings @ main.js:4526

3. Now lets make a compilation error so the overlay appears, just put a ~ in print.js.

After you save the file, the browser will receive a HMR update and an overlay containing a error like this appears:

Failed to compile.

./print.js
Module parse failed: /home/gabriel/Repos/webpack-overlay-bug/print.js Unexpected token (3:0)
You may need an appropriate loader to handle this file type.
| export default function printMe() {
|   console.log('Hello');~
| };
| 
 @ ./index.js 1:0-33 21:2-26:4 21:34-26:3
 @ multi (webpack)-dev-server/client?https://localhost:8080 webpack/hot/only-dev-server ./index.js

4. Now, remove the ~ making the error.

The overlay should've disappeared, but because there are warnings it does not disappear.

How it should behave (removing warnings)

Go to the webpack.config.js file and change the performance configuration to

performance: {
  hints: false
  // hints: "warning"
}

This will remove the performance warnings. Save the file, restart the server and do steps 2 to 4 again. This time you should see no warnings in your browser console and the overlay will disappear once you remove the ~.