dillon1000/react

Fix infinite update loop that happens when an unmemoized value is passed to useDeferredValue (#24247)

* Fix infinite loop if unmemoized val passed to uDV

The current implementation of useDeferredValue will spawn a new
render any time the input value is different from the previous one. So
if you pass an unmemoized value (like an inline object), it will never
stop spawning new renders.

The fix is to only defer during an urgent render. If we're already
inside a transition, retry, offscreen, or other non-urgen render, then
we can use the latest value.

* Temporarily disable "long nested update" warning

DevTools' timeline profiler warns if an update inside a layout effect
results in an expensive re-render. However, it misattributes renders
that are spawned from a sync render at lower priority. This affects the
new implementation of useDeferredValue but it would also apply to things
like Offscreen.

It's not obvious to me how to fix this given how DevTools models the
idea of a "nested update" so I'm disabling the warning for now to
unblock the bugfix for useDeferredValue.