enzyme-adapter-react-15.4 incompatible with react/react-dom 15.3

[edmorley]

Hi!

The Enzyme docs (here) say to use enzyme-adapter-react-15.4 when using React 15.0-15.4.

As of #1234 / #1252, react-addons-test-utils is no longer a peerDependency of enzyme-adapter-react-15.4, but a normal dependency. This means that instead of the user being able to specify a suitable version, the adapter uses the version range 15.0.0-0 - 15.4.x, which resolves to 15.4.2, and so is incompatible with react/react-dom 15.3.x.

For example when using:

  "dependencies": {
    "react": "15.3.2",
    "react-dom": "15.3.2",
    ...
  },
  "devDependencies": {
    "enzyme": "3.1.0",
    "enzyme-adapter-react-15.4": "1.0.2",
    ...
  }

...enzyme-adapter-react-15.4 pulls in react-addons-test-utils 15.4.2, which contains:

module.exports = require('react-dom/lib/ReactTestUtils');

...which doesn't exist in react-dom 15.3.2, and so results in:

Module not found: Error: Can't resolve 'react-dom/lib/ReactTestUtils' in '....\node_modules\react-addons-test-utils'

Compare this to react-addons-test-utils 15.3.2, which contains:

module.exports = require('react/lib/ReactTestUtils');

I would presume the solutions to be either:

1. Revert the peer dependency change for move react-addons-test-utils to dependencies #1234 / Make react-test-renderer a dependency instead of a peer dependency #1252 for older versions of the adapter.
2. Create a new enzyme-adapter-react-15.3 that has a reduced version range for react-addons-test-utils.

Many thanks :-)

CC @brucewpaul, @ljharb, @bdwain.

[ljharb]

Interesting, that's a consequence that we didn't think of, and the reason that it needs to be a peer dep.

I'm thinking maybe we should revert the changes for all the adapters. @brucewpaul, @bdwain, thoughts?

[bdwain]

I think 15.4 is a special case and in general within the same major version should be fine. I'm not totally familiar with what happened that required a change for react 15.4, but I don't think this would be an issue for react 16 or 15.5+. I'm not totally sure about 13 or 14 though. But i think it's best to only revert where there's a clear problem, which seems to just be 15.4.

Also, is it possible that the version range for the 15.4 adapter is just wrong? Maybe it should be < 15.4, not <= 15.4. Something seems to have changed between 15.3 and 15.4 that broke 15.4.

[ljharb]

@bdwain does that mean you're saying that using a 15.6 test-utils would work with 15.5, for example?

It's certainly possible that we need adapters for all of 15-15.3, 15.4, and 15.5+.

[bdwain]

react addons test utils 15.6.2 has a peer dependency on "react-dom": "^15.4.2", so as long your version of react dom matches that it should be good.

[ljharb]

ok, so are we looking at a specific case where react 15.3 breaks with test utils for 15.4, but that's not true for any other major line?

[bdwain]

I'll investigate all of these tonight and get back to you.

[bdwain]

I think I misread v 15.6.2's peer dependency. it's actually ^15.6.2. It looks like they've had a policy of bumping the peer dependency of react-test-renderer to match its version, so that react had to be at least as new. This may not have been a hard requirement, but it still causes npm ls to fail.

I opened an issue about this and it sounds like for version 16 they may be willing to change their policy and leave the peer dependency at ^16.0.0`. facebook/react#11278

I think we will need to revert the change for everything but 16.0, but it sounds like we can leave 16.0 as a regular dependency (they are still on 16.0.0 anyway).

I can open this PR later

[ljharb]

Makes sense.

[bdwain]

#1301 should fix this @edmorley @ljharb