Breaking changes in 18.19.0 (including The --loader flag was deprecated in Node v20.6.0)

[everett1992]

Version

18.19.0

Platform

Linux ua0683ea36b1857.ant.amazon.com 5.15.0-91-generic #101~20.04.1-Ubuntu SMP Thu Nov 16 14:22:28 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

various

What steps will reproduce the bug?

I'm seeing various failures in our CI builds after upgrading 18.18.0 to 18.19.0, including an error for a flag that is deprecated in node 20.6.0

(tsx 3) errors on flag deprecated in 20

$ node -v
v18.19.0
$ npx tsx@3 index.ts

node:internal/process/esm_loader:40
      internalBinding('errors').triggerUncaughtException(
                                ^
Error: tsx must be loaded with --import instead of --loader
The --loader flag was deprecated in Node v20.6.0
    at X (file:///home/ANT.AMAZON.COM/calebev/tmp/node_modules/tsx/dist/esm/index.mjs:1:1920)
    at Hooks.addCustomLoader (node:internal/modules/esm/hooks:202:24)
    at Hooks.register (node:internal/modules/esm/hooks:168:16)
    at async initializeHooks (node:internal/modules/esm/utils:167:5)
    at async customizedModuleWorker (node:internal/modules/esm/worker:104:24)

Node.js v18.19.0

(jest 28) TypeError: Cannot assign to read only property 'performance' of object '[object global]'

$ node -v
v18.19.0
$  echo "jest.useFakeTimers()" > jest.test.js
$ npx jest@28 jest.test.js
 FAIL  ./jest.test.js
  ● Test suite failed to run

    TypeError: Cannot assign to read only property 'performance' of object '[object global]'

    > 1 | jest.useFakeTimers()
        |                     ^
      2 |

      at hijackMethod (node_modules/@sinonjs/fake-timers/src/fake-timers-src.js:946:32)
      at Object.install (node_modules/@sinonjs/fake-timers/src/fake-timers-src.js:1733:17)
      at FakeTimers.useFakeTimers (node_modules/@jest/fake-timers/build/modernFakeTimers.js:110:36)
      at Object.<anonymous> (jest.test.js:1:21)

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

No breaking changes between minor versions of an LTS release

What do you see instead?

Breaking changes, including a reference to a flag that is deprecated in a greater major version.

Additional information

No response

[connor4312]

In Node 18, the loader flag was marked as experimental for which they say:

The feature is not subject to semantic versioning rules. Non-backward compatible changes or removal may occur in any future release. Use of the feature is not recommended in production environments.

[targos]

The error seems to be thrown by your dependency tsx. --loader still works in v18.19.0.

[everett1992]

I'll try to create simple reproductions without dependencies. We have a few hundred packages failing to build with 18.19.0 that are building successfully with 18.18.0. Most are fixed by updating their dependencies to versions that work with node 20.

I'll accept that loader is experimental, but the error message should at least read deprecated in 18.19.0 instead of 20.6.0.

[targos]

The error message does not come from us. It is thrown by the tsx package.

[aduh95]

Breaking existing code is painful, but it's a tradeoff to be made between having two different implementations between 18.x and the other release lines – which is a maintenance burden, both for us and for loaders/hooks authors. It's unfortunate that the package you are using is hiding the fact that it's using an experimental API (by default, Node.js emits a warning when you use the --loader flag), and in hindsight the decision to put a hardcoded version in the warning was probably a mistake, so you should report that to them (but IIRC major loader implementors (incl tsx) have been involved in the backport process and some have released patched versions even before Node.js v18.19.0 was out, so maybe try upgrading your deps first).

Breaking changes in experimental APIs is considered fair game, and the incorrect warning is not emitted by us, closing as it seems there's nothing to be done on Node.js side.

[everett1992]

Thanks for the well thought out response, I understand closing the issue, I figured this was caused by undefined or experimental behaviors.

Do you have any pointers for the issues we see in Jest?

    TypeError: Cannot assign to read only property 'performance' of object '[object global]'