Uncaught Error: Unexpected object passed to ReactTestInstance constructor (tag: 13). This is probably a bug in React.

[pedroteixeira]

Hello,

I'm testing v16.3.0 and I'm getting this warning:

Warning: Detected multiple renderers concurrently rendering the same context provider. This is currently unsupported 

My use case is that I wanted to render React Test Renderer (for ex) from a Component in an another (ReactDOM) renderer but it does not seem to work - I wanted to use same Provider in both containers.

I thought React.createContext create objects with no state and could be shared across renderers / Fiber containers.. Is there workaround for this? Are there any thoughts on this, Is this a definite behaviour?

Following the warning, I eventually get the error message which I believe is related to the warning:

Uncaught Error: Unexpected object passed to ReactTestInstance constructor (tag: 13). This is probably a bug in React.

thank you for any guidance :)

[gaearon]

@acdlite What was the main reason it was stateful?

[pedroteixeira]

I tried to make a reproducible case here, but it worked :)
https://runkit.com/pedroteixeira/testing-react/1.0.0

I'll close this issue for now, and when I managed to create a reproducible snippet fort the case I have, I'll share it again.

But it would be good to hear more about if the new Contexts Providers can be safely used without any hidden state attached to the current fiber container.

thanks for the great library!

[sahrens]

I'm seeing this error when switching to React.forwardRef - I'm guessing react-test-renderer may need to be updated to support forwardRef better?

[sahrens]

Ah, just saw #12693, maybe this is resolved by #12725?

[gaearon]

@sahrens You're sure you're using 16.4.0? If you can create a small repro case that would help.

[sahrens]

@gaearon: works after upgrading to 16.4 :)

[sahrens]

Although React.StrictMode and React.Fragment cause similar problems, but are easy to work around by wrapping in a trivial component.

[gaearon]

Can you prepare a test case please? Again, I wouldn’t expect to see this problem for any type. You shouldn’t need to work around it; I thought I fixed it. A full reproducing case would help me see what’s missing.

[stereobooster]

For future searchers. I see this error with enzyme https://github.com/stereobooster/react-context-issue (I guess this is not an issue in React itself)