Return the true value of an AsyncComputedVar when called via get_var_value() (#6391)

* Actually return the value of an AsyncComputedVar

* Actually return the value of an AsyncComputedVar

* Fix linting

* Fixing newline error

* Fixing local state var case

* test(state): add regression test for get_var_value with async computed vars

Reproduces the bug fixed in #6391
where get_var_value returned the un-awaited coroutine for an async computed
var instead of the underlying value.

https://claude.ai/code/session_01PLGmhJG9HNUzobmBRXQUnc

* Extend test case for slow path

* Handle ValueError in _run_lifespan_tasks helper

Fix rare regression failure during app startup.

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Masen Furer <m_github@0x26.net>

Author: 3 people

reflex/state.py

@@ -1753,13 +1753,19 @@ async def get_var_value(self, var: Var[VAR_TYPE]) -> VAR_TYPE:
             raise UnretrievableVarValueError(msg)
         # Fastish case: this var belongs to this state
         if var_data.state == self.get_full_name():
-            return getattr(self, var_data.field_name)
+            value = getattr(self, var_data.field_name)
+            if inspect.isawaitable(value):
+                return await value
+            return value
 
         # Slow case: this var belongs to another state
         other_state = await self.get_state(
             self._get_root_state().get_class_substate(var_data.state)
         )
-        return getattr(other_state, var_data.field_name)
+        value = getattr(other_state, var_data.field_name)
+        if inspect.isawaitable(value):
+            return await value
+        return value
 
     def _mark_dirty_computed_vars(self) -> None:
         """Mark ComputedVars that need to be recalculated based on dirty_vars."""

tests/units/test_state.py

@@ -4396,6 +4396,46 @@ async def test_get_var_value(
     }
 
 
+@pytest.mark.asyncio
+async def test_get_var_value_async_computed_var(
+    token: str, attached_mock_event_context: EventContext
+):
+    """Test that get_var_value awaits async computed vars and returns their value.
+
+    Regression test for https://github.com/reflex-dev/reflex/pull/6391: previously
+    get_var_value returned the un-awaited coroutine for async computed vars rather
+    than the underlying value.
+
+    Args:
+        token: A token.
+        attached_mock_event_context: An event context that will be attached to the app's state manager.
+    """
+
+    class StateWithAsyncCV(BaseState):
+        """A state with an async computed var."""
+
+        base: int = 5
+
+        @rx.var(cache=True)
+        async def doubled(self) -> int:
+            return self.base * 2
+
+    class Substate(StateWithAsyncCV):
+        """A substate to test get_var_value across states."""
+
+    state_manager = attached_mock_event_context.state_manager
+    state = await state_manager.get_state(
+        BaseStateToken(ident=token, cls=StateWithAsyncCV)
+    )
+
+    # Fast path
+    assert await state.get_var_value(StateWithAsyncCV.doubled) == 10
+
+    # Slow path
+    substate = await state.get_state(Substate)
+    assert await substate.get_var_value(StateWithAsyncCV.doubled) == 10
+
+
 @pytest.mark.asyncio
 async def test_async_computed_var_get_state(
     token: str, attached_mock_event_context: EventContext