eager tasks

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## Unreleased
+
+### Changed
+
+- Eager tasks are now enabled On Python3.12 and above https://github.com/Textualize/textual/pull/6102
+
 ## [6.1.0] - 2025-08-01
 
 ### Added

src/textual/app.py

@@ -2098,6 +2098,7 @@ async def run_app(app: App[ReturnType]) -> None:
                 await pilot._wait_for_screen()
                 yield pilot
             finally:
+                await asyncio.sleep(0)
                 # Shutdown the app cleanly
                 await app._shutdown()
                 await app_task
@@ -2166,7 +2167,9 @@ async def run_auto_pilot(
 
         self._thread_init()
 
-        app._loop = asyncio.get_running_loop()
+        loop = app._loop = asyncio.get_running_loop()
+        if hasattr(asyncio, "eager_task_factory"):
+            loop.set_task_factory(asyncio.eager_task_factory)
         with app._context():
             try:
                 await app._process_messages(
@@ -3442,7 +3445,6 @@ def _register_child(
             self._registry.add(child)
             child._attach(parent)
             child._post_register(self)
-            child._start_messages()
 
     def _register(
         self,
@@ -3495,6 +3497,7 @@ def _register(
                     self._register(widget, *widget._nodes, cache=cache)
         for widget in new_widgets:
             apply_stylesheet(widget, cache=cache)
+            widget._start_messages()
 
         if not self._running:
             # If the app is not running, prevent awaiting of the widget tasks

src/textual/dom.py

@@ -409,13 +409,22 @@ def children(self) -> Sequence["Widget"]:
 
     @property
     def displayed_children(self) -> Sequence[Widget]:
-        """The displayed children (where node.display==True).
+        """The displayed children (where `node.display==True`).
 
         Returns:
             A sequence of widgets.
         """
         return self._nodes.displayed
 
+    @property
+    def displayed_and_visible_children(self) -> Sequence[Widget]:
+        """The displayed children (where `node.display==True` and `node.visible==True`).
+
+        Returns:
+            A sequence of widgets.
+        """
+        return self._nodes.displayed_and_visible
+
     @property
     def is_empty(self) -> bool:
         """Are there no displayed children?"""

src/textual/message_pump.py

@@ -586,7 +586,6 @@ async def _pre_process(self) -> bool:
                     await self._dispatch_message(events.Mount())
             else:
                 await self._dispatch_message(events.Mount())
-            self.check_idle()
             self._post_mount()
         except Exception as error:
             self.app._handle_exception(error)
@@ -620,7 +619,7 @@ async def _process_messages_loop(self) -> None:
         """Process messages until the queue is closed."""
         _rich_traceback_guard = True
         self._thread_id = threading.get_ident()
-
+        await asyncio.sleep(0)
         while not self._closed:
             try:
                 message = await self._get_message()

src/textual/widget.py

@@ -717,10 +717,10 @@ def _cover(self, widget: Widget) -> None:
         self._uncover()
         self._cover_widget = widget
         widget._parent = self
-        widget._start_messages()
         widget._post_register(self.app)
         self.app.stylesheet.apply(widget)
         self.refresh(layout=True)
+        widget._start_messages()
 
     def _uncover(self) -> None:
         """Remove any widget, previously set via [`_cover`][textual.widget.Widget._cover]."""

src/textual/widgets/_directory_tree.py

@@ -525,7 +525,7 @@ def _load_directory(self, node: TreeNode[DirEntry]) -> list[Path]:
             key=lambda path: (not self._safe_is_dir(path), path.name.lower()),
         )
 
-    @work(exclusive=True)
+    @work()
     async def _loader(self) -> None:
         """Background loading queue processor."""
         worker = get_current_worker()

src/textual/widgets/_footer.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 from collections import defaultdict
 from itertools import groupby
 from typing import TYPE_CHECKING
@@ -311,7 +312,8 @@ def _on_mouse_scroll_up(self, event: events.MouseScrollUp) -> None:
                 event.stop()
                 event.prevent_default()
 
-    def on_mount(self) -> None:
+    async def on_mount(self) -> None:
+        await asyncio.sleep(0)
         self.call_next(self.bindings_changed, self.screen)
 
         def bindings_changed(screen: Screen) -> None:

src/textual/widgets/_placeholder.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from itertools import cycle
-from typing import TYPE_CHECKING, Iterator
+from typing import TYPE_CHECKING
 from weakref import WeakKeyDictionary
 
 from typing_extensions import Literal, Self
@@ -13,6 +13,7 @@
 if TYPE_CHECKING:
     from textual.app import RenderResult
 
+from textual._context import NoActiveAppError
 from textual.css._error_tools import friendly_list
 from textual.reactive import Reactive, reactive
 from textual.widget import Widget
@@ -84,7 +85,7 @@ class Placeholder(Widget):
     """
 
     # Consecutive placeholders get assigned consecutive colors.
-    _COLORS: WeakKeyDictionary[App, Iterator[str]] = WeakKeyDictionary()
+    _COLORS: WeakKeyDictionary[App, int] = WeakKeyDictionary()
     _SIZE_RENDER_TEMPLATE = "[b]{} x {}[/b]"
 
     variant: Reactive[PlaceholderVariant] = reactive[PlaceholderVariant]("default")
@@ -125,17 +126,22 @@ def __init__(
         self.variant = self.validate_variant(variant)
         """The current variant of the placeholder."""
 
+        try:
+            self._COLORS[self.app] = self._COLORS.setdefault(self.app, -1) + 1
+            self._color_offset = self._COLORS[self.app]
+        except NoActiveAppError:
+            self._color_offset = 0
+
         # Set a cycle through the variants with the correct starting point.
         self._variants_cycle = cycle(_VALID_PLACEHOLDER_VARIANTS_ORDERED)
         while next(self._variants_cycle) != self.variant:
             pass
 
     async def _on_compose(self, event: events.Compose) -> None:
         """Set the color for this placeholder."""
-        colors = Placeholder._COLORS.setdefault(
-            self.app, cycle(_PLACEHOLDER_BACKGROUND_COLORS)
-        )
-        self.styles.background = f"{next(colors)} 50%"
+        color_count = len(_PLACEHOLDER_BACKGROUND_COLORS)
+        color = _PLACEHOLDER_BACKGROUND_COLORS[self._color_offset % color_count]
+        self.styles.background = f"{color} 50%"
 
     def render(self) -> RenderResult:
         """Render the placeholder.

src/textual/widgets/_toast.py

@@ -144,6 +144,7 @@ class ToastRack(Container, inherit_css=False):
 
     DEFAULT_CSS = """
     ToastRack {
+        display: none;
         layer: _toastrack;
         width: 1fr;
         height: auto;
@@ -175,6 +176,7 @@ def show(self, notifications: Notifications) -> None:
         Args:
             notifications: The notifications to show.
         """
+        self.display = bool(notifications)
         # Look for any stale toasts and remove them.
         for toast in self.query(Toast):
             if toast._notification not in notifications: