Select warning fires repeatedly

[arackaf]

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

See fiddle https://jsfiddle.net/j2nzg31L/1/

The warning related to the select fires repeatedly. @gaearon tells me it should dedupe, and that this is a bug.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template for React 16: https://jsfiddle.net/Luktwrdm/, template for React 15: https://jsfiddle.net/hmbg7e9w/).

See above

What is the expected behavior?

See above

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

16.2

[gaearon]

We should deduplicate this warning (like we do with many other warnings).

[watadarkstar]

@gaearon Hi Dan, I can take this. I imagine its similar to: #11113 and #11216

[gaearon]

Yep. Sounds good!

[watadarkstar]

@gaearon

Hi Dan, I wanted to check with you that I am on the right track before I try writing any code.

So here is the warning:

react/packages/react-dom/src/client/ReactDOMFiberOption.js

Lines 36 to 45 in d9869a4

	export function validateProps(element: Element, props: Object) {
	// TODO (yungsters): Remove support for `selected` in <option>.
	if (__DEV__) {
	warning(
	props.selected == null,
	'Use the `defaultValue` or `value` props on <select> instead of ' +
	'setting `selected` on <option>.',
	);
	}
	}

I'm not sure if I should be writing a test in:

• react-dom/src/tests/ReactDOMSelect-test.js
• react-dom/src/tests/ReactDOMOption-test.js

And I don't see a test that already tests for this warning - am I missing something? Or should I write a entirely new test in one of those files?

I haven't worked with the test suite before so I'm not sure how its supposed to be organized.

[gaearon]

I don't think it matters which file you write it in.

To verify if there are any existing tests, you can just comment out the warning and run npm test. If nothing fails, well, yeah, then we didn't have tests for it.

[gaearon]

Thanks!

[arackaf]

Wow that was incredibly fast - great work ❤️