drop uploaded_files, don't allow state_id for mixins

Author: benedikt-bartscher

reflex/state.py

@@ -556,7 +556,17 @@ def __init_subclass__(
 
         super().__init_subclass__(**kwargs)
 
-        # Store state_id as class variable
+        # Mixin states cannot have state_id
+        if cls._mixin:
+            if state_id is not None:
+                msg = (
+                    f"Mixin state '{cls.__module__}.{cls.__name__}' cannot have a state_id. "
+                    "Remove state_id or mixin=True."
+                )
+                raise StateValueError(msg)
+            return
+
+        # Store state_id as class variable (only for non-mixins)
         cls._state_id = state_id
 
         # Validate state_id if provided (check for duplicates)
@@ -575,9 +585,6 @@ def __init_subclass__(
                     raise StateValueError(msg)
             _state_id_registry[state_id] = cls
 
-        if cls._mixin:
-            return
-
         # Handle locally-defined states for pickling.
         if "<locals>" in cls.__qualname__:
             cls._handle_local_def()

tests/units/test_state_minification.py

@@ -174,3 +174,10 @@ class MixinState(BaseState, mixin=True):
         assert MixinState._state_id is None
         # Mixin states have _mixin = True set, so get_name isn't typically called
         # but the class should be created without error
+
+    def test_mixin_with_state_id_raises(self):
+        """Test that mixin states cannot have state_id."""
+        with pytest.raises(StateValueError, match="cannot have a state_id"):
+
+            class MixinWithId(BaseState, mixin=True, state_id=999):
+                pass