fix: tasks did not have a stable key, causing hot reloads to miss values

maartenbreddels · maartenbreddels · commit e1567f9d03cb · 2025-04-30T12:59:13.000+02:00
The key of the task was used also for the reactive variables, so if a
reload with 2 users caused the keys to change, both pages would see a
missing values. On later reloads it could go back to the old value again.
diff --git a/solara/tasks.py b/solara/tasks.py
@@ -772,12 +772,15 @@ def Page():
     def wrapper(f: Union[None, Callable[P, Union[Coroutine[Any, Any, R], R]]]) -> Task[P, R]:
         # we use wraps to make the key of the reactive variable more unique
         # and less likely to mixup during hot reloads
+        assert f is not None
+        key = solara.toestand._create_key_callable(f)
+
         @functools.wraps(f)  # type: ignore
         def create_task():
             if inspect.iscoroutinefunction(f):
-                return TaskAsyncio[P, R](prefer_threaded and has_threads, f, key=solara.toestand._create_key_callable(create_task))
+                return TaskAsyncio[P, R](prefer_threaded and has_threads, f, key=key)
             else:
-                return TaskThreaded[P, R](cast(Callable[P, R], f), key=solara.toestand._create_key_callable(create_task))
+                return TaskThreaded[P, R](cast(Callable[P, R], f), key=key)
 
         return cast(Task[P, R], Proxy(create_task))
 
diff --git a/solara/toestand.py b/solara/toestand.py
@@ -442,7 +442,7 @@ def _check_mutation(self):
             raise ValueError(msg)
 
 
-def _create_key_callable(f: Callable[[], S]):
+def _create_key_callable(f: Callable):
     try:
         prefix = f.__qualname__
     except Exception:
