refactor: use custom value NOT_SET = object() instead of None to signal the absence of a value for the default_value parameter in AutorunOptions and internally in Autorun class for properties storing last selector result and last call result

Author: sassanh

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Upcoming
+
+- refactor: use custom value `NOT_SET = object()` instead of `None` to signal the absence of a value for the `default_value` parameter in `AutorunOptions` and internally in `Autorun` class for properties storing last selector result and last call result
+
 ## Version 0.24.0
 
 - chore: add badges in `README.md` and classifiers in `pyproject.toml`

redux/autorun.py

@@ -17,6 +17,7 @@
 )
 
 from redux.basic_types import (
+    NOT_SET,
     Action,
     Args,
     AutoAwait,
@@ -133,7 +134,7 @@ def __init__(  # noqa: C901, PLR0912
         )
         self._options = options
 
-        self._last_selector_result: SelectorOutput | None = None
+        self._last_selector_result: SelectorOutput | None = NOT_SET
         self._last_comparator_result: ComparatorOutput = cast(
             'ComparatorOutput',
             object(),
@@ -268,7 +269,7 @@ def call(
     ) -> None:
         """Call the wrapped function with the current state of the store."""
         func = self._func() if isinstance(self._func, weakref.ref) else self._func
-        if func and self._last_selector_result is not None:
+        if func and self._last_selector_result is not NOT_SET:
             value: ReturnType = call_func(
                 func,
                 [self._last_selector_result],
@@ -282,7 +283,7 @@ def call(
                     is False  # only explicit `False` disables auto-await, not `None`
                 ):
                     if (
-                        self._latest_value is not None
+                        self._latest_value is not NOT_SET
                         and isinstance(self._latest_value, AwaitableWrapper)
                         and not self._latest_value.awaited
                     ):

redux/basic_types.py

@@ -153,6 +153,8 @@ class StoreOptions(Immutable, Generic[Action, Event]):
 
 AutoAwait = TypeVar('AutoAwait', bound=Literal[True, False, None], infer_variance=True)
 
+NOT_SET = object()
+
 
 class AutorunOptionsType(Immutable, Generic[ReturnType, AutoAwait]):
     default_value: ReturnType | None = None
@@ -218,7 +220,7 @@ def __init__(  # noqa: PLR0913
 
 
 class AutorunOptionsImplementation(Immutable, Generic[ReturnType, AutoAwait]):
-    default_value: ReturnType | None = None
+    default_value: ReturnType | None = cast('None', NOT_SET)
     auto_await: AutoAwait = cast('AutoAwait', val=None)
     initial_call: bool = True
     reactive: bool = True

tests/results/test_snapshot_fixture/monitor/store-000.jsonc

@@ -1,2 +1,2 @@
 // store-000
-1
+null

tests/results/test_snapshot_fixture/monitor/store-001.jsonc

@@ -1,2 +1,2 @@
 // store-001
-3
+1

tests/results/test_snapshot_fixture/monitor/store-002.jsonc

@@ -0,0 +1,2 @@
+// store-002
+null

tests/results/test_snapshot_fixture/monitor/store-003.jsonc

@@ -0,0 +1,2 @@
+// store-003
+3

tests/results/test_snapshot_fixture/monitor/store-004.jsonc

@@ -0,0 +1,2 @@
+// store-004
+null