Support React 16.3

[theKashey]

Currently, we rely on componentWillReceiveProps to perform sync update and sync forceUpdate. So - this method does not exist anymore.

We have 2 options:
1 - rely on subrender, ie async updates. It is a dev mode, nobody cares about double rendering on rare hot updates. Thus remove AppContainer completely. This will also solve
2 - find another way. But I don't see any.

[oliviertassinari]

Would it also explain why I see a warning anytime is use getDerivedStateFromProps()?
I'm assuming react-hot-loader is hijacking the components and add componentWillReceiveProps .

[gregberge]

Yes, new challenge to come!

[theKashey]

++ we have to test how new ("real") Context API works, as long "Context" is not a "Tag" or a function - it is a brand new element type. Should be fine, but even enzyme itself failing :)

[theKashey]

@oliviertassinari - yeah, RHL is adding componentWillReceiveProps, and I am going just to drop it.

[swashata]

Had just this issue right now. I am very new to react, just started and had to scratch my head (like a lot) to understand this isn't coming from mine, rather the hot loader 😁 . I will be waiting for an update.

[gaearon]

I don't understand what this means:

rely on subrender, ie async updates.

[theKashey]

@gaearon - this is a local meme( #830 ), about performing hot-render each time you "can do it". V3 uses AppContainer to start an update, v4 can use AppContainer to perform sync updates, and Component.render to perform async updates. Async cos they could be executed after the main update or main update could not "render into them" - code splitting, resource load, portals, and so on. Plus we have to defer .forceUpdate, as long shall not call it from a render method.
Basically - this one line - https://github.com/gaearon/react-hot-loader/blob/master/src/proxy/createClassProxy.js#L164

[gaearon]

What are you using componentWillReceiveProps for today?

[theKashey]

Nothing but to being able "flush"(forceUpdate) changes. As I pointed above - we could safely remove it. It may cause double renders, but this is not something we should avoid.
Plus, if you move updates from a timeout to componentDidUpdate - they will be not so very deferred.

[gaearon]

Got it. componentWillReceiveProps is a bad place to call forceUpdate so that sounds good.

[theKashey]

PS: Is there any "new"(~fiber) way to trigger re-render? Is there any way to re-render SFC without a real Component on top of it? Is there any a bit more "soft" ways to update?