fix: Preserve event_actions from @rx.event decorator in mixin event handlers (reflex-dev#6099)

* fix: Preserve event_actions from @rx.event decorator in mixin event handlers

* add constant

Author: benedikt-bartscher

reflex/event.py

@@ -89,6 +89,7 @@ def substate_token(self) -> str:
 _EVENT_FIELDS: set[str] = {f.name for f in dataclasses.fields(Event)}
 
 BACKGROUND_TASK_MARKER = "_reflex_background_task"
+EVENT_ACTIONS_MARKER = "_rx_event_actions"
 
 
 @dataclasses.dataclass(
@@ -2311,6 +2312,7 @@ class EventNamespace:
 
     # Constants
     BACKGROUND_TASK_MARKER = BACKGROUND_TASK_MARKER
+    EVENT_ACTIONS_MARKER = EVENT_ACTIONS_MARKER
     _EVENT_FIELDS = _EVENT_FIELDS
     FORM_DATA = FORM_DATA
     upload_files = upload_files
@@ -2461,7 +2463,7 @@ def wrapper(
             # Store decorator event actions on the function for later processing
             event_actions = _build_event_actions()
             if event_actions:
-                func._rx_event_actions = event_actions  # pyright: ignore [reportFunctionMemberAccess]
+                setattr(func, EVENT_ACTIONS_MARKER, event_actions)
             return func  # pyright: ignore [reportReturnType]
 
         if func is not None:

reflex/state.py

@@ -42,6 +42,7 @@
 from reflex.environment import PerformanceMode, environment
 from reflex.event import (
     BACKGROUND_TASK_MARKER,
+    EVENT_ACTIONS_MARKER,
     Event,
     EventHandler,
     EventSpec,
@@ -753,6 +754,9 @@ def _copy_fn(fn: Callable) -> Callable:
         newfn.__annotations__ = fn.__annotations__
         if mark := getattr(fn, BACKGROUND_TASK_MARKER, None):
             setattr(newfn, BACKGROUND_TASK_MARKER, mark)
+        # Preserve event_actions from @rx.event decorator
+        if event_actions := getattr(fn, EVENT_ACTIONS_MARKER, None):
+            object.__setattr__(newfn, EVENT_ACTIONS_MARKER, event_actions)
         return newfn
 
     @staticmethod
@@ -1255,7 +1259,7 @@ def _create_event_handler(
             The event handler.
         """
         # Check if function has stored event_actions from decorator
-        event_actions = getattr(fn, "_rx_event_actions", {})
+        event_actions = getattr(fn, EVENT_ACTIONS_MARKER, {})
 
         return event_handler_cls(
             fn=fn, state_full_name=cls.get_full_name(), event_actions=event_actions

tests/units/test_state.py

@@ -3737,6 +3737,21 @@ def test_bare_mixin_state() -> None:
     assert ChildBareMixinState.get_root_state() == State
 
 
+def test_mixin_event_handler_preserves_event_actions() -> None:
+    """Test that event_actions from @rx.event decorator are preserved when inherited from mixins."""
+
+    class EventActionsMixin(BaseState, mixin=True):
+        @rx.event(prevent_default=True, stop_propagation=True)
+        def handle_with_actions(self):
+            pass
+
+    class UsesEventActionsMixin(EventActionsMixin, State):
+        pass
+
+    handler = UsesEventActionsMixin.handle_with_actions
+    assert handler.event_actions == {"preventDefault": True, "stopPropagation": True}
+
+
 def test_assignment_to_undeclared_vars():
     """Test that an attribute error is thrown when undeclared vars are set."""