Extracted from https://github.com/facebook/react/issues/12643.

We're currently diff a host node in the complete phase even if it has bailed out in the begin phase. By itself, this just means we're doing a little bit more work than necessary. But it also has some observable effects. In particular, https://github.com/facebook/react/issues/13424 (which by itself would be very rare and probably not worth fixing) is made worse because we end up committing update to inputs from another component.

I have a fix for this in https://github.com/facebook/react/pull/13423. Filing this for posterity.
childSet: Array<Instance | TextInstance>,
          child: Instance | TextInstance,
        ): void {
          childSet.push(child);
        },
        finalizeContainerChildren(
          container: Container,
          newChildren: Array<Instance | TextInstance>,
        ): void {},
        replaceContainerChildren(
          container: Container,
          newChildren: Array<Instance | TextInstance>,
        ): void {
          container.children = newChildren;
        },
      };
  const NoopRenderer = reconciler(hostConfig);
  const rootContainers = new Map();
  const roots = new Map();
  const DEFAULT_ROOT_ID = '<default>';
  let yieldedValues = null;
  let unitsRemaining;
  function* flushUnitsOfWork(n: number): Generator<Array<mixed>, void, void> {
    let didStop = false;
    while (!didStop && scheduledCallback !== null) {
      let cb = scheduledCallback;
      scheduledCallback = null;
      unitsRemaining = n;
      cb({
        timeRemaining() {