React v16: Error during mount causes instance to never be removed from mountedInstances

I’m guessing componentWillUnmount isn’t called. Would a fix be to listen to componentDidCatch, splice the array as in componentWillUnmount and then rethrow the error?

[bvaughn]

I also wonder whether the side effect should occur in componentDidUpdate or componentWillUpdate - there’s often a case for a side effect to occur before render rather than after

Side effects are only safe in the commit phase (after render).

[gaearon]

I think maybe the right fix is for every component in their commit-phase hooks to find the root component (through context) and cause it to call setState on itself (maybe passing depth as an argument).

Components themselves just return this.props.children from render so that should always be memoized and setState on the root shouldn’t cause a deep re-render. Since we’re already inside the lifecycle, it should get batched and be processed after all such setStates. Resulting in a single “flush” after all inner components have updated their props.

Finally, the root component flushes changes in its own componentDidUpdate hook.