Webpack 5 - Memory Leak

Bug report

What is the current behavior?

When I make a change in my web app and Webpack compiles, memory usage seems to increase. If I keep making changes and Webpack keeps re-compiling, memory usage will continue to climb. In a large project I work in, it takes about 10 compilations until Webpack crashes with a “Allocation failed - JavaScript heap out of memory” exception.

If the current behavior is a bug, please provide the steps to reproduce.

Please see the minimal repo I created to reproduce the issue: https://github.com/smparsons/webpack-memory-leak-issue. The instructions to reproduce are on the README.

What is the expected behavior?

I would expect some kind of garbage collection to happen in between compilations.

Other relevant information: webpack version: 5.0.0-beta.15 Node.js version: 11.10.1 Operating System: macOS Catalina Version 10.15 Additional tools:

[sokra]

Do not use any kind of hash in the filename during development when using webpack-dev-middleware. Each compilation will create a new file as filename changes. Just like files will pile up on disk, they will pile up in memory as the webpack-dev-middleware stores output files in memory.

[joshxyzhimself]

This one does the trick, right?

{
    output: {
      filename: mode === 'production' ? '[chunkhash].js' : '[name].js',
      chunkFilename: mode === 'production' ? '[chunkhash].js' : '[name].js',
    },
}