ReactDOMServer.renderToStaticMarkup gets stuck while trying to render Portals

[amoshg]

Calling ReactDOMServer.renderToStaticMarkup(elementWithPortal); gets stuck in a loop while trying to do a static render.

Current behavior:
The behavior can be seen here: https://codepen.io/anon/pen/BmqWOM by un-commenting line 58 (warning: this will make your tab freeze)

Expected behavior:
It should return with results or throw some kind of error if the input is not valid

[gaearon]

Want to dig into why this happens? I'd expect an error there.

[amoshg]

It seems to enter this while loop while (out.length < bytes) {...} inside ReactDOMServerRenderer.prototype.read and the stack keeps building up elements indefinitely causing an infinite loop. Not familiar with the render loop but could it be caused by a circular reference somewhere?

Is it not possible for it return the markup? What kind of error would you expect?

[aweary]

It looks like it's because React.isValidElement returns false for Portals, so resolve in ReactPartialRenderer keeps returning the same Portal element, which keeps getting pushed into the stack

[gaearon]

I think we want to throw when isValidElement is false. We fail for objects, don't we?

[gaearon]

Oh. We used to fail in toArray(). But now it actually accepts portals. I guess we need an explicit check somewhere.

[aweary]

So is the expected behavior that we throw an error when trying to render a Portal using ReactDOMServer?

[gaearon]

Yes. You can't render them anyway because they throw on a missing DOM node. And you can't have a DOM node on the server. So you're supposed to skip them in the server code.