Bug: useTransition and uSES do not work together, uT is not resilient to amount-of-render about react

[dai-shi]

I'm not sure if it's described well in react-18 WG discussions (I think there was a tweet about it from Seb.), but the "Sync" is important. It's not useExternalStore. So, it's not a bug per se. It's a designed limitation.

[alexeyraspopov]

I hit the same behavior and it was far from obvious in my case, because uSES wasn't the one that supposed to be triggering suspense. I created this sandbox https://codesandbox.io/s/upbeat-flower-2gnhm6 to show that the shim implementation (use-sync-external-store itself, before it got rerouted to the React hook implementation) didn't have this behavior and was working in the way I as a user would expect: when suspending render is triggered via useTransition, I can use pending flag instead of suspense boundary for UI feedback.

Screen.Recording.2023-06-19.at.11.37.48.mov