[Flight] Forward debugInfo from awaited instrumented Promises (#33415)
Stacked on #33403. When a Promise is coming from React such as when it's passed from another environment, we should forward the debug information from that environment. We already do that when rendered as a child. This makes it possible to also `await promise` and have the information from that instrumented promise carry through to the next render. This is a bit tricky because the current protocol is that we have to read it from the Promise after it resolves so it has time to be assigned to the promise. `async_hooks` doesn't pass us the instance (even though it has it) when it gets resolved so we need to keep it around. However, we have to be very careful because if we get this wrong it'll cause a memory leak since we retain things by `asyncId` and then manually listen for `destroy()` which can only be called once a Promise is GC:ed, which it can't be if we retain it. We have to therefore use a `WeakRef` in case it never resolves, and then read the `_debugInfo` when it resolves. We could maybe install a setter or something instead but that's also heavy. The other issues is that we don't use native Promises in ReactFlightClient so our instrumented promises aren't picked up by the `async_hooks` implementation and so we never get a handle to our thenable instance. To solve this we can create a native wrapper only in DEV.
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Sebastian Markbåge committed
37054867c15a7381abe0f73d98f3fecd06da52da
Parent: d742611
Committed by GitHub <[email protected]>
on 6/4/2025, 4:49:03 AM