System:
  OS: macOS 15.6
  CPU: (10) arm64 Apple M1 Max
  Memory: 393.00 MB / 64.00 GB
  Shell: 5.9 - /bin/zsh
Binaries:
  Node: 22.15.0 - ~/.volta/tools/image/node/22.15.0/bin/node
  Yarn: 4.9.1-git.20250411.hash-1908ee79f - ~/.volta/tools/image/yarn/4.9.1/bin/yarn
  npm: 10.9.2 - ~/.volta/tools/image/node/22.15.0/bin/npm
  pnpm: 10.11.0 - ~/.volta/bin/pnpm
Browsers:
  Brave Browser: 137.1.79.126
  Chrome: 139.0.7258.128
  Safari: 18.6
npmPackages:
  unplugin: ^2.3.6 => 2.3.6 

# create base folder
mkdir unplugin-repro-loader-crash
cd unplugin-repro-loader-crash
# add dependencies (rspack + unplugin)
pnpm add -D unplugin @rspack/core @rspack/cli
mkdir src
# entry point - imports a .custom file
echo 'const test = require("./test.custom"); console.log(test);' > src/index.js
# dummy content
echo 'TEST STRING' > src/test.custom
# plugin for .custom files - throwing on load
cat << EOF > custom-loader.js
const { createUnplugin } = require("unplugin");

module.exports = createUnplugin(() => ({
  name: "custom-plugin",
  load: {
    filter: {
      id: /\.custom$/,
    },
    handler(id) {
      throw id
    },
  },
}));
EOF
# basic configuration
cat << EOF > rspack.config.js
const { defineConfig } = require("@rspack/cli");
const CustomLoader = require("./custom-loader");

module.exports = defineConfig({
  entry: "./src/index.js",
  plugins: [CustomLoader.rspack()],
});
EOF
# crashes because of an unhandled promise rejection :(
pnpm rspack build

node:internal/process/promises:389
      new UnhandledPromiseRejection(reason);
      ^

UnhandledPromiseRejection: This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason "/Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/src/test.custom".
    at throwUnhandledRejectionsMode (node:internal/process/promises:389:7)
    at processPromiseRejections (node:internal/process/promises:470:17)
    at process.processTicksAndRejections (node:internal/process/task_queues:96:32) {
  code: 'ERR_UNHANDLED_REJECTION'
}

Node.js v20.15.1

ERROR in ./src/test.custom
  × Module build failed:
  ╰─▶   × Error: /Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/src/test.custom
        │     at Object.load (file:///Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/node_modules/.pnpm/unplugin@2.3.6/node_modules/unplugin/dist/rspack/loaders/load.js:22:17)
        │     at /Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/node_modules/.pnpm/@rspack+core@1.4.11/node_modules/@rspack/core/dist/index.js:3050:29
        │     at node:internal/util:431:7
        │     at new Promise (<anonymous>)
        │     at node:internal/util:417:12
        │     at isomorphoicRun (/Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/node_modules/.pnpm/@rspack+core@1.4.11/node_modules/@rspack/core/dist/index.js:3549:244)
        │     at runLoaders (/Users/julien.elbaz/dev/experiments/unplugin-repro-loader-crash/node_modules/.pnpm/@rspack+core@1.4.11/node_modules/@rspack/core/dist/index.js:3599:145)
      


Rspack compiled with 1 error in 71 ms