useForwardedRef incorrectly updates the ref during the render phase #6551
Description
In #5462 the function useForwardedRef was changed so that now the ref is mutated during the render phase of React. This violates React’s expected invariant that render functions have no side-effects and conflicts with Concurrent React.
In some cases React warns about that in the console with: “Cannot update a component while rendering a different component. To locate the bad setState() ...”
In the latest master, notice how one updateRef is correctly in an effect, and the other is outside of an effect:
Lines 15 to 21 in 7c45cc9
Expected Behavior
useForwardedRef should only mutate ref in the useEffect.
Actual Behavior
useForwardedRef mutates ref outside of an effect.