createElement does not warn about props.__proto__ being null, fails instead

[alitaheri]

This is a bug in React.createElement code:

React.createElement does not warn if props.__proto__ is null ( from Object.create(null) ) since it believes that to be a plain object originating from #6134. But since it directly accesses hasOwnProperty it fails if such object is passed as props.

Reproduce:

const props = Object.create(null);
React.createElement(() => null, props);

What is the expected behavior?
It shouldn't use hasOwnProperty directly on props if such object is expected.

React: 15.1.0
Browsers: All
OS: All

This affects all versions of React but since after 15.1.0 the acceptable shape of props is explicitly defined then it should be explicitly supported as well.

[bloodyowl]

how about just use Object.prototype.hasOwnProperty.call(config, key)?

[gaearon]

how about just use Object.prototype.hasOwnProperty.call(config, key)?

Sounds good, would you like to send a PR with a fix and a test case?

[alitaheri]

@gaearon Sure, but I need to know how would the community want it fix, support prototype-less objects or just fail with reason.

+1 for support prototype-less objects 😁

[gaearon]

+1 for support prototype-less objects

Sure, I don’t see why not. I think we did support them, and we just regressed when we added a warning. Thanks!

[gaearon]

Fixed in #6855.