Error [DataCloneError] when using watch mode on build

[rmehner]

👋,

I'm running into this weird build issue and I'm a bit at loss, maybe someone has an idea:

Versions:

Node 16.7.0
macOS 11.5.2 (20G95)
esbuild: 0.12.22

build.js:

const { buildSync } = require('esbuild')

buildSync({
  entryPoints: ['./src/index.ts'],
  outfile: './dist/index.js',
  watch: true
})

index.js:

console.log('Hello world!')

Running node build.js will lead to an error message:

esbuild-data-clone-error/node_modules/esbuild/lib/main.js:1875
      throw reject;
      ^

Error [DataCloneError]: () => {
              if (isStopped)
                return;
              isStopped = true;
              watc...<omitted>... } could not be cloned.
    at esbuild-data-clone-error/node_modules/esbuild/lib/main.js:1913:22
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  code: 25,
  INDEX_SIZE_ERR: 1,
  DOMSTRING_SIZE_ERR: 2,
  HIERARCHY_REQUEST_ERR: 3,
  WRONG_DOCUMENT_ERR: 4,
  INVALID_CHARACTER_ERR: 5,
  NO_DATA_ALLOWED_ERR: 6,
  NO_MODIFICATION_ALLOWED_ERR: 7,
  NOT_FOUND_ERR: 8,
  NOT_SUPPORTED_ERR: 9,
  INUSE_ATTRIBUTE_ERR: 10,
  INVALID_STATE_ERR: 11,
  SYNTAX_ERR: 12,
  INVALID_MODIFICATION_ERR: 13,
  NAMESPACE_ERR: 14,
  INVALID_ACCESS_ERR: 15,
  VALIDATION_ERR: 16,
  TYPE_MISMATCH_ERR: 17,
  SECURITY_ERR: 18,
  NETWORK_ERR: 19,
  ABORT_ERR: 20,
  URL_MISMATCH_ERR: 21,
  QUOTA_EXCEEDED_ERR: 22,
  TIMEOUT_ERR: 23,
  INVALID_NODE_TYPE_ERR: 24,
  DATA_CLONE_ERR: 25
}

However, the index.js file in /dist is emitted just fine. Removing the watch option makes this work without a hitch.

Any pointers much appreciated. I've set up a repo with the exact error so you can try on your machine if you want 👉🏿 https://github.com/rmehner/esbuild-data-clone-error

Thanks in advance!

[evanw]

Watch mode is intended to be used with asynchronous builds. Use the build API instead of the buildSync API as shown in the documentation: https://esbuild.github.io/api/#watch. I'll update buildSync to throw an error when watch: true is present.

[rmehner]

@evanw thanks for the help there. It used to work, that's why I was confused. Changing to the build API shouldn't be much of a problem. Thanks again!

[evanw]

Yes, it used to work. This regression is a result of speeding up the *Sync APIs by running them on another thread that keeps the underlying child process around and shares it between API calls. In that model, it's no longer possible to have result objects with function properties because they can't be cloned across threads.

[rmehner]

Thank you, I've updated to the new esbuild version (that was fast) and fixed my build configuration (it really was just a switch from buildSync to build)

Awesome work, thanks a lot!