Error from component causes error to be thrown twice

[guyfedwards]

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

What is the current behavior?
If a component throws not in render, for example in a click handler, the error is thrown twice instead of once. Error boundaries stop the double reporting, but only handle errors thrown in render, not errors in handlers etc.

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: https://jsfiddle.net/ebsrpraL/).
https://codepen.io/anon/pen/GMjEpx?editors=0010

What is the expected behavior?
Just one error thrown

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?
16.0.0-rc.2

[gaearon]

Error boundaries don’t (currently) catch errors coming from event handlers. The blog post goes into more detail about this:

Error boundaries catch errors during rendering, in lifecycle methods, and in constructors of the whole tree below them.

[guyfedwards]

Thats ok but the error still seems to be rethrown resulting in two errors being caught in window.onerror

[gaearon]

This seems like the same discussion as #10474.