[Bug]: Too many files open error when using builtin:swc-loader

[KidkArolis]

System Info

System:
OS: macOS 15.1
CPU: (8) arm64 Apple M1
Memory: 146.88 MB / 8.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 22.9.0 - ~/.asdf/installs/nodejs/22.9.0/bin/node
npm: 10.8.3 - ~/.asdf/plugins/nodejs/shims/npm
pnpm: 9.11.0 - ~/.asdf/shims/pnpm
Watchman: 2024.09.09.00 - /opt/homebrew/bin/watchman

Details

If I replace swc-loader with builtin:swc-loader I get the following error on every build:

× Module build failed:
╰─▶ × Too many open files (os error 24), failed to read

Here's the relevant bit of rspack config:

{
    test: /\.(js|mjs|jsx)$/,
    exclude: /(node_modules)/,
    use: [
      {
        loader: 'builtin:swc-loader',
        // loader: require.resolve('swc-loader'),
        options: {
          env: {
            targets: browsers.query(options),
            coreJs: 3,
            mode: 'entry'
          },
          jsc: {
            parser: {
              syntax: 'ecmascript',
              exportDefaultFrom: true,
              jsx: true
            },
            externalHelpers: true,
            transform: {}
          }
        }
      }
    ]
  }

My ulimit is low with ulimit -n showing 256. But if I update with ulimit -n 64000 that doesn't help.

Reproduce link

No response

Reproduce Steps

Unsure at this time, doesn't reproduce on a smaller repo, only on my larger production app. Can try and put together a large example.. But maybe you know why this error would be thrown.

[KidkArolis]

Ah, but an interesting here is that all the errors are on reading .scss files specifically, which are also css modules. Is something off when converting those to JS? Example:

ERROR in ./src/pages/Profile/components/Verified/Verified.scss
  × Module build failed:
  ╰─▶   × Error: HookWebpackError:   × Module build failed:
        │   ╰─▶   × Error: EMFILE: too many open files, open '/Users/karolis/app/client/styles/foundation/duration.scss'

[KidkArolis]

OK, if I use both require('swc-loader') for js + require('postcss-loader') for scss, that works. But builtin:swc-loader with require('postcss-loader') does not work. But using builtin:swc-loader and removing require('postcss-loader') from the chain builds successfully.

[KidkArolis]

Also happens when using builtin:swc-loader with builtin:lightningcss-loader, but more rarely.