Merge branch 'main' into overall-important

.github/workflows/pythonpackage.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Install and configure Poetry
         uses: snok/install-poetry@v1.3.3
         with:
-          version: 1.2.2
+          version: 1.4.2
           virtualenvs-in-project: true
       - name: Install dependencies
         run: poetry install --extras "dev"

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Fixed `!important` not applying to `outline` https://github.com/Textualize/textual/issues/2420
 - Fixed `outline-right` not being recognised https://github.com/Textualize/textual/issues/2446
 
+### Added
+
+- Watch methods can now optionally be private https://github.com/Textualize/textual/issues/2382
+
 ## [0.22.3] - 2023-04-29
 
 ### Fixed

src/textual/reactive.py

@@ -241,9 +241,13 @@ class Reactive(Generic[ReactiveType]):
                     events.Callback(callback=partial(await_watcher, watch_result))
                 )
 
-        watch_function = getattr(obj, f"watch_{name}", None)
-        if callable(watch_function):
-            invoke_watcher(watch_function, old_value, value)
+        private_watch_function = getattr(obj, f"_watch_{name}", None)
+        if callable(private_watch_function):
+            invoke_watcher(private_watch_function, old_value, value)
+
+        public_watch_function = getattr(obj, f"watch_{name}", None)
+        if callable(public_watch_function):
+            invoke_watcher(public_watch_function, old_value, value)
 
         # Process "global" watchers
         watchers: list[tuple[Reactable, Callable]]

tests/test_reactive.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import asyncio
 
 import pytest
@@ -386,3 +388,25 @@ async def test_watch_compute():
         assert app.show_ac is False
 
     assert watch_called == [True, True, False, False, True, True, False, False]
+
+
+async def test_public_and_private_watch() -> None:
+    """If a reactive/var has public and private watches both should get called."""
+
+    calls: dict[str, bool] = {"private": False, "public": False}
+
+    class PrivateWatchTest(App):
+        counter = var(0, init=False)
+
+        def watch_counter(self) -> None:
+            calls["public"] = True
+
+        def _watch_counter(self) -> None:
+            calls["private"] = True
+
+    async with PrivateWatchTest().run_test() as pilot:
+        assert calls["private"] is False
+        assert calls["public"] is False
+        pilot.app.counter += 1
+        assert calls["private"] is True
+        assert calls["public"] is True