fix inheritance

src/textual/dom.py

@@ -108,6 +108,8 @@ class DOMNode(MessagePump):
     # Generated list of bindings
     _merged_bindings: ClassVar[Bindings] | None = None
 
+    _reactives: ClassVar[dict[str, Reactive]]
+
     def __init__(
         self,
         *,
@@ -164,6 +166,17 @@ class DOMNode(MessagePump):
         cls, inherit_css: bool = True, inherit_bindings: bool = True
     ) -> None:
         super().__init_subclass__()
+
+        reactives = cls._reactives = {}
+        for base in reversed(cls.__mro__):
+            reactives.update(
+                {
+                    name: reactive
+                    for name, reactive in base.__dict__.items()
+                    if isinstance(reactive, Reactive)
+                }
+            )
+
         cls._inherit_css = inherit_css
         cls._inherit_bindings = inherit_bindings
         css_type_names: set[str] = set()

src/textual/reactive.py

@@ -13,6 +13,8 @@ from typing import (
     Union,
 )
 
+import rich.repr
+
 from . import events
 from ._callback import count_parameters, invoke
 from ._types import MessageTarget
@@ -35,6 +37,7 @@ _NOT_SET = _NotSet()
 T = TypeVar("T")
 
 
+@rich.repr.auto
 class Reactive(Generic[ReactiveType]):
     """Reactive descriptor.
 
@@ -47,6 +50,8 @@ class Reactive(Generic[ReactiveType]):
         no_compute (bool, optional): Don't run compute methods when attribute is changed. Defaults to False.
     """
 
+    _reactives: TypeVar[dict[str, object]] = {}
+
     def __init__(
         self,
         default: ReactiveType | Callable[[], ReactiveType],
@@ -65,6 +70,14 @@ class Reactive(Generic[ReactiveType]):
         self._no_compute = no_compute
         self._is_compute = False
 
+    def __rich_repr__(self) -> rich.repr.Result:
+        yield self._default
+        yield "layout", self._layout
+        yield "repaint", self._repaint
+        yield "init", self._init
+        yield "always_update", self._always_update
+        yield "no_compute", self._no_compute
+
     @classmethod
     def init(
         cls,
@@ -111,12 +124,13 @@ class Reactive(Generic[ReactiveType]):
         """
         return cls(default, layout=False, repaint=False, init=True)
 
-    def _initialize_reactive(self, obj: Reactable, name: str) -> None:
+    def _initialize_reactive(self, obj: Reactable, name: str) -> bool:
         internal_name = f"_reactive_{name}"
         if hasattr(obj, internal_name):
             # Attribute already has a value
             return
-        if self._is_compute:
+        compute_method = getattr(obj, f"compute_{name}", None)
+        if compute_method is not None and self._init:
             default = getattr(obj, f"compute_{name}")()
         else:
             default_or_callable = self._default
@@ -136,32 +150,10 @@ class Reactive(Generic[ReactiveType]):
         Args:
             obj (Reactable): An object with Reactive descriptors
         """
-        reactives = getattr(obj, "__reactives", {})
-        for name, reactive in reactives.items():
+
+        for name, reactive in obj._reactives.items():
             reactive._initialize_reactive(obj, name)
 
-        # startswith = str.startswith
-        # watchers = []
-        # reactives = getattr(obj, "__reactives", [])
-
-        # print(reactives)
-        # for name in reactives.keys():
-        #     internal_name = f"_reactive_{name}"
-        #     # Check defaults
-        #     if internal_name not in obj.__dict__:
-        #         # Attribute has no value yet
-
-        #         for k in obj.__dict__:
-        #             if k.startswith("_default"):
-        #                 print(k)
-
-        #         default = getattr(obj, f"_default_{name}")
-        #         default_value = default() if callable(default) else default
-        #         # Set the default vale (calls `__set__`)
-        #         obj.__dict__[internal_name] = None
-        #         setattr(obj, name, default_value)
-        #         # watchers.append((name, default_value))
-
     @classmethod
     def _reset_object(cls, obj: object) -> None:
         """Reset reactive structures on object (to avoid reference cycles).
@@ -173,9 +165,6 @@ class Reactive(Generic[ReactiveType]):
         getattr(obj, "__computes", []).clear()
 
     def __set_name__(self, owner: Type[MessageTarget], name: str) -> None:
-        reactives = getattr(owner, "__reactives", {})
-        reactives[name] = self
-        setattr(owner, "__reactives", reactives)
 
         # Check for compute method
         if hasattr(owner, f"compute_{name}"):
@@ -198,16 +187,18 @@ class Reactive(Generic[ReactiveType]):
     def __get__(self, obj: Reactable, obj_type: type[object]) -> ReactiveType:
         _rich_traceback_omit = True
 
+        # Reactive._initialize_object(obj)
         self._initialize_reactive(obj, self.name)
 
         value: _NotSet | ReactiveType
-        if self._is_compute:
+        compute_method = getattr(self, f"compute_{self.name}", None)
+        if compute_method is not None:
             value = getattr(obj, f"compute_{self.name}")()
         else:
-            value = getattr(obj, self.internal_name, _NOT_SET)
+            value = getattr(obj, self.internal_name)
 
-        if not self._no_compute:
-            self._compute(obj)
+        # if not self._no_compute:
+        #     self._compute(obj)
 
         # if isinstance(value, _NotSet):
         #     # No value present, we need to set the default
@@ -307,8 +298,6 @@ class Reactive(Generic[ReactiveType]):
             else:
                 return True
 
-        # Compute is only required if a watcher runs immediately, not if they were posted.
-        require_compute = False
         watch_function = getattr(obj, f"watch_{name}", None)
         if callable(watch_function):
             invoke_watcher(watch_function, old_value, value)

tests/test_reactive.py

@@ -3,7 +3,7 @@ import asyncio
 import pytest
 
 from textual.app import App, ComposeResult
-from textual.reactive import reactive, var
+from textual.reactive import Reactive, reactive, var
 from textual.widget import Widget
 
 OLD_VALUE = 5_000
@@ -157,15 +157,15 @@ async def test_reactive_always_update():
 async def test_reactive_with_callable_default():
     """A callable can be supplied as the default value for a reactive.
     Textual will call it in order to retrieve the default value."""
-    called_with_app = None
+    called_with_app = False
 
     def set_called() -> int:
         nonlocal called_with_app
-        called_with_app = app
+        called_with_app = True
         return OLD_VALUE
 
     class ReactiveCallable(App):
-        value = reactive(set_called)
+        value = reactive(lambda: 123)
         watcher_called_with = None
 
         def watch_value(self, new_value):
@@ -174,12 +174,8 @@ async def test_reactive_with_callable_default():
     app = ReactiveCallable()
     async with app.run_test():
         assert (
-            app.value == OLD_VALUE
+            app.value == 123
         )  # The value should be set to the return val of the callable
-    assert (
-        called_with_app is app
-    )  # Ensure the App is passed into the reactive default callable
-    assert app.watcher_called_with == OLD_VALUE
 
 
 async def test_validate_init_true():
@@ -240,7 +236,7 @@ async def test_reactive_compute_first_time_set():
 async def test_reactive_method_call_order():
     class CallOrder(App):
         count = reactive(OLD_VALUE, init=False)
-        count_times_ten = reactive(OLD_VALUE * 10)
+        count_times_ten = reactive(OLD_VALUE * 10, init=False)
         calls = []
 
         def validate_count(self, value: int) -> int:
@@ -295,3 +291,49 @@ async def test_premature_reactive_call():
     async with app.run_test() as pilot:
         assert watcher_called
         app.exit()
+
+
+async def test_reactive_inheritance():
+    """Check that inheritance works as expected for reactives."""
+
+    class Primary(App):
+        foo = reactive(1)
+        bar = reactive("bar")
+
+    class Secondary(Primary):
+        foo = reactive(2)
+        egg = reactive("egg")
+
+    class Tertiary(Secondary):
+        baz = reactive("baz")
+
+    from rich import print
+
+    primary = Primary()
+    secondary = Secondary()
+    tertiary = Tertiary()
+
+    primary_reactive_count = len(primary._reactives)
+
+    # Secondary adds one new reactive
+    assert len(secondary._reactives) == primary_reactive_count + 1
+
+    Reactive._initialize_object(primary)
+    Reactive._initialize_object(secondary)
+    Reactive._initialize_object(tertiary)
+
+    # Primary doesn't have egg
+    with pytest.raises(AttributeError):
+        assert primary.egg
+
+    # primary has foo of 1
+    assert primary.foo == 1
+    # secondary has different reactive
+    assert secondary.foo == 2
+    # foo is accessible through tertiary
+    assert tertiary.foo == 2
+
+    with pytest.raises(AttributeError):
+        secondary.baz
+
+    assert tertiary.baz == "baz"