Returning an error if a PropType is passed to ReactPropTypes.oneOf.

[ventuno]

I took where @philipshurpik left off with #6940 to fix #1919, as that PR can't be merged anymore and is more than a month old.

@philipshurpik, if you meant to keep on working on #6940, please let me know and I'll close this one.

The idea is to return a PropTypeError whenever one of ReactPropTypes is passed to ReactPropTypes.oneOf. The error message, hints that the user might be meaning to use ReactPropTypes.oneOfType instead.

1. If createChainableTypeChecker is called with an expectedType we add the expectedType flag to the checkType function (see [1])
2. In createEnumTypeChecker.validate, if expectedValues[i] is of type function and it has the expectedType flag, we know that a ReactPropTypes has been passed, so we throw the error described above
3. As per Improve proptypes oneof warnings - Fixes #1919 #6940, if a generic function is passed to ReactPropTypes.oneOf we improve the previous output to display "Unexpected function" and the function converted to string

As a side note, I noticed that if getPropType is called with undefined, we get the following exception:
Cannot read property '@@toStringTag' of undefined
Is this expected?

[1] https://github.com/facebook/react/pull/6940/files#r68511156

[donavon]

maybe something like this instead?

return values.map(value => (
  getPropType(value) === 'function' ? `Unexpected function: ${value}` : value
));

You shouldn't have to specially call toString on value.

[ventuno]

Good idea, @donavon. Thanks a lot, I implemented your recommended change :-).

[ventuno]

Dear @aweary and @gaearon, I just noticed there was some activity about this PR [1]. So I decided to fix the merging issues. Can you kindly review?

[1] #8274 (comment)

[gaearon]

Sorry about this! We've been busy with a React rewrite this year, and haven't really paid attention to PRs. :-(

This code has moved to https://github.com/facebook/prop-types so you can make a PR there and we could review.