dive() breaks when using the new context API.

[stellarhoof]

Describe the bug

The new React context elements (https://reactjs.org/docs/context.html) report their type as objects instead of functions (custom react components) or strings (native react components), which breaks dive(). I haven't tested whether other methods of ShallowWrapper break.

To Reproduce

https://codesandbox.io/s/zxj4898zxp?module=%2Fsrc%2FApp.test.js

Expected behavior

shallow and dive should implement actual render semantics when handling the new context API:

1. Automatically update current context whenever a context provider is encountered and remove the provider node from the tree.
2. Automatically pass the current context to childs of context consumer nodes and remove the consumer node from the tree.

I'm sure the above are not the exact semantics, but at least the most intuitive.

[ljharb]

If you're using the latest version of react-test-renderer (you may need to rm -rf node_modules && npm install, or mess with your lockfile), is this still a problem?

[anthonator]

@ljharb I can confirm that I am seeing this error when using the latest version of react-test-renderer. I'm also using @KevinGrandon's enzyme-react-adapter-future. Not sure if that's relevant.

Also, just for reference, this is the error I'm seeing:

TypeError: ShallowWrapper::dive() can only be called on components

[anthonator]

Also, just for reference, this is what debug outputs on the dive just before receiving the above error:

<[object Object] value={{...}}>
  ...snip...
</[object Object]>

[ljharb]

@anthonator thanks - could you provide a complete minimal test case?

[anthonator]

@ljharb I believe @stellarhoof already provided a test case. Is there something more you need?

[anthonator]

@ljharb https://codesandbox.io/s/9l1rk4l20y?module=%2Fsrc%2FApp.test.js

Let me know if this is what you're looking for.

[joeldenning]

+1 I'm seeing the same problem.

[paddotk]

I just upgraded to Enzyme 3.4.1 but still getting the same error (TypeError: ShallowWrapper::dive() can only be called on components). Did the fix work for anyone else?

[ljharb]

@paddotk it's not been fixed yet.

[OzzieOrca]

Is there any way we can help with this? I tried digging into the code a little while ago and found it hard to follow. If I remember correctly, bypassing this check (and the error message it throws) https://github.com/airbnb/enzyme/blob/0bbdc988b149b8e75ff8cb530ab740b0459ce43d/packages/enzyme/src/ShallowWrapper.js#L1411 casued issues later on. I'm not really sure what needs to be done. I could try playing with it again.

I would love to move forward with an upgrade and this is the only thing holding us back as we've used dive a lot of places in our tests.

[ljharb]

@OzzieOrca the issue, I think, is a bit deeper than that. Although shallow takes a context option, that context is not filtered down to match the contextTypes of the component; getChildContext() is not taken into account, and the new child context is also not provided to the dived component and filtered down by contextTypes.

[OzzieOrca]

That's helpful, thanks. I might take a look at it again sometime soon unless someone more knowledgeable is able to jump on it.

[alexandrudanpop]

Is there a workaround for this issue? Getting this when testing redux connected components.

[ljharb]

@alexandrudanpop downgrade to react-redux < 6, iirc.

[OzzieOrca]

Unless I'm missing something redux is only at 4.0.1. https://github.com/reduxjs/redux/releases

Nvm. Assuming you meant react-redux. I should try that...

[csvan]

I would love to help here if possible, can I get some pointers on where to start? Currently, this completely blocks us from moving to either react-redux 6.0 or styled-components 4.0, both which use the new Context API and completely break under shallow.

[ljharb]

@csvan the two pieces I'm waiting for are #1960 and then #1966; after those go in, I suspect it'll be relatively short work to get full createContext support.

[csvan]

@ljharb I apologise for being a nag, but what is the status on those PR:s being merged? Can we assist in any way?

[ljharb]

I've just landed #1960, and rebased #1966 (which needs some more work). I'm hopeful to make a release soon.