Version

29.4.2 (i.e. latest)

Steps to reproduce

[My apologies for a long report here but as the title says, I've run into multiple related issues that I think are best presented as a whole.]

Setup: Create a directory with the following three files:

package.json

{
  "type": "module",
  "devDependencies": { "jest": "29" },
  "scripts": {
    "test": "NODE_OPTIONS=--experimental-vm-modules jest"
  }
}

data.json

{ "hello": "world" }

index.spec.js

import data from './data.json';
console.log('Imported data', data);

it('works with json imports', function() {})

Issue 1: Releasing a BREAKING CHANGE in a minor update

From the release notes, version 29.4.0 introduced this change:

[jest-runtime] Enforce import assertions when importing JSON in ESM (#12755 & #13805)

In the directory you've just created...

$ npm install

$ npm test

 FAIL  ./index.spec.js
  ● Test suite failed to run

    Module "file:///private/tmp/foo/data.json" needs an import assertion of type "json"

      at Runtime.validateImportAssertions (node_modules/jest-runtime/build/index.js:624:25)
          at async Promise.all (index 0)

Test Suites: 1 failed, 1 total

As expected from the release notes, the test fails due to the missing import assertion. But this used to work in previous minor versions! For example ...

$ npm i -D jest@29.3

$ jest --version
29.4.2

Wait, what?!? I specifically installed v29.3. Why do I still have 29.4.2??

This brings us to ...

Issue 2: Can't install previous minor versions of jest

Apparently this is a thiing with jest? No matter what minor version you install, you end up getting the latest minor version for it? npm i jest@27.0.0 installs 27.5.1? npm i jest@28.0.0 installs 28.1.3?

I won't bore you with the details, but for others who might be reading this, it has to do with how jest is just a thin wrapper around a whole ecosystem of "...jest..." modules that all depend on semver "^"-prefixed dependencies, and how that manifests when installing modules.

This is both unexpected and magical. And, in the case of issue 1, above, not a little bit painful. It mean there's no viable way of reverting to the most recent version of jest that didn't have this behavior (v29.3.1). The most recent "pinnable" version is v28.1.3, which breaks stuff for a bunch of other reasons.

Still with me? 😄

We can, however, sort of revert to 29.3.1 by manually overriding everything via NPM's overrides feature. To do so, add the following overrides section to the package.json file:

  "overrides": {
    "@jest/console": "29.3",
    "@jest/core": "29.3",
    "@jest/environment": "29.3",
    "@jest/expect": "29.3",
    "@jest/expect-utils": "29.3",
    "@jest/fake-timers": "29.3",
    "@jest/globals": "29.3",
    "@jest/reporters": "29.3",
    "@jest/schemas": "29",
    "@jest/source-map": "29",
    "@jest/test-result": "29.3",
    "@jest/test-sequencer": "29.3",
    "@jest/transform": "29.3",
    "@jest/types": "29.3",
    "babel-jest": "29.3",
    "babel-plugin-jest-hoist": "29",
    "babel-preset-jest": "29",
    "diff-sequences": "29.3",
    "expect": "29.3",
    "jest-changed-files": "29",
    "jest-circus": "29.3",
    "jest-config": "29.3",
    "jest-diff": "29.3",
    "jest-docblock": "29",
    "jest-each": "29.3",
    "jest-environment-node": "29.3",
    "jest-get-type": "29",
    "jest-haste-map": "29.3",
    "jest-leak-detector": "29.3",
    "jest-matcher-utils": "29.3",
    "jest-message-util": "29.3",
    "jest-mock": "29.3",
    "jest-regex-util": "29",
    "jest-resolve": "29.3",
    "jest-resolve-dependencies": "29.3",
    "jest-runner": "29.3",
    "jest-runtime": "29.3",
    "jest-snapshot": "29.3",
    "jest-util": "29.3",
    "jest-validate": "29.3",
    "jest-watcher": "29.3",
    "jest-worker": "29.3",
    "pretty-format": "29.3"
  }

This is the very definition of "fugly" - so much so I don't see being able to justify doing this as part of a real project - but it gets the job done for testing purposes here ...

$ \rm package-lock.json && npm install

$ jest --version
29.3.1  #  YAY! It worked!

$ npm test
 PASS  ./index.spec.js
  ✓ works with json imports (1 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.454 s
Ran all test suites.

**NOTICE: Our test passes under 29.3.1... meaning (and I hope you'll agree) that this does in fact represent a BREAKING CHANGE which should have been released as v30.

Issue 3: Import assertions have been demoted from TC39 stage 3 back to stage 2

To complicate matters further, while poking around with this issue, I noticed this statement that TC39 added to the import-assertions README a couple days ago:

⚠️ This proposal has been demoted from Stage 3 to Stage 2 in January 2023 due to whatwg/html#7233. TC39 is working on a solution, which will require relaxing the "assert only" semantics and potentially changing the syntax. Import assertions have already been shipped in some implementations, consider the current instability when using them.

Expected behavior

• Don't release breaking changes as minor updates
• Provide a way to easily pin jest to specific minor versions
• Revert the requirement for import assertions in light of the proposal having been demoted

I'll leave it at this, as I expect you folks will have already discussed some of this, or need to discuss this further.

Actual behavior

See previous sections...

Additional context

No response

Environment

System:
    OS: macOS 13.0
    CPU: (10) x64 Apple M1 Max
  Binaries:
    Node: 16.18.0 - ~/.nvm/versions/node/v16.18.0/bin/node
    Yarn: 1.22.19 - ~/.nvm/versions/node/v16.18.0/bin/yarn
    npm: 8.19.3 - ~/.nvm/versions/node/v16.18.0/bin/npm
  npmPackages:
    jest: 29 => 29.4.2