Don't apply Input "select on focus" behaviour when app is focused

CHANGELOG.md

@@ -5,6 +5,16 @@ 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
+
+### Added
+
+- Added `from_app_focus` to `Focus` event to indicate if a widget is being focused because the app itself has regained focus or not https://github.com/Textualize/textual/pull/5379
+
+### Changed
+
+- The content of an `Input` will now only be automatically selected when the widget is focused by the user, not when the app itself has regained focus (similar to web browsers). https://github.com/Textualize/textual/pull/5379
+
 ## [1.0.0] - 2024-12-12
 
 ### Added
@@ -14,7 +24,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added `system` boolean to Binding, which hides the binding from the help panel https://github.com/Textualize/textual/pull/5352
 - Added support for double/triple/etc clicks via `chain` attribute on `Click` events https://github.com/Textualize/textual/pull/5369
 - Added `times` parameter to `Pilot.click` method, for simulating rapid clicks https://github.com/Textualize/textual/pull/5369
-
+- Text can now be select using mouse or keyboard in the Input widget https://github.com/Textualize/textual/pull/5340
+
 ### Changed
 
 - Breaking change: Change default quit key to `ctrl+q` https://github.com/Textualize/textual/pull/5352

src/textual/app.py

@@ -4052,7 +4052,9 @@ def _watch_app_focus(self, focus: bool) -> None:
                     # ...settle focus back on that widget.
                     # Don't scroll the newly focused widget, as this can be quite jarring
                     self.screen.set_focus(
-                        self._last_focused_on_app_blur, scroll_visible=False
+                        self._last_focused_on_app_blur,
+                        scroll_visible=False,
+                        from_app_focus=True,
                     )
             except NoScreen:
                 pass

src/textual/command.py

@@ -776,7 +776,7 @@ def compose(self) -> ComposeResult:
         with Vertical(id="--container"):
             with Horizontal(id="--input"):
                 yield SearchIcon()
-                yield CommandInput(placeholder=self._placeholder)
+                yield CommandInput(placeholder=self._placeholder, select_on_focus=False)
                 if not self.run_on_select:
                     yield Button("\u25b6")
             with Vertical(id="--results"):

src/textual/events.py

@@ -16,10 +16,10 @@
 from dataclasses import dataclass
 from pathlib import Path
 from typing import TYPE_CHECKING, Type, TypeVar
-from typing_extensions import Self
 
 import rich.repr
 from rich.style import Style
+from typing_extensions import Self
 
 from textual._types import CallbackType
 from textual.geometry import Offset, Size
@@ -722,8 +722,22 @@ class Focus(Event, bubble=False):
 
     - [ ] Bubbles
     - [ ] Verbose
+
+    Args:
+        from_app_focus: True if this focus event has been sent because the app itself has
+            regained focus (via an AppFocus event). False if the focus came from within
+            the Textual app (e.g. via the user pressing tab or a programmatic setting
+            of the focused widget).
     """
 
+    def __init__(self, from_app_focus: bool = False) -> None:
+        self.from_app_focus = from_app_focus
+        super().__init__()
+
+    def __rich_repr__(self) -> rich.repr.Result:
+        yield from super().__rich_repr__()
+        yield "from_app_focus", self.from_app_focus
+
 
 class Blur(Event, bubble=False):
     """Sent when a widget is blurred (un-focussed).

src/textual/screen.py

@@ -869,12 +869,20 @@ def _update_focus_styles(
                 [widget for widget in widgets if widget._has_focus_within], animate=True
             )
 
-    def set_focus(self, widget: Widget | None, scroll_visible: bool = True) -> None:
+    def set_focus(
+        self,
+        widget: Widget | None,
+        scroll_visible: bool = True,
+        from_app_focus: bool = False,
+    ) -> None:
         """Focus (or un-focus) a widget. A focused widget will receive key events first.
 
         Args:
             widget: Widget to focus, or None to un-focus.
             scroll_visible: Scroll widget in to view.
+            from_app_focus: True if this focus is due to the app itself having regained
+                focus. False if the focus is being set because a widget within the app
+                regained focus.
         """
         if widget is self.focused:
             # Widget is already focused
@@ -899,7 +907,7 @@ def set_focus(self, widget: Widget | None, scroll_visible: bool = True) -> None:
                 # Change focus
                 self.focused = widget
                 # Send focus event
-                widget.post_message(events.Focus())
+                widget.post_message(events.Focus(from_app_focus=from_app_focus))
                 focused = widget
 
                 if scroll_visible:

src/textual/widgets/_input.py

@@ -641,7 +641,7 @@ def _on_blur(self, event: Blur) -> None:
 
     def _on_focus(self, event: Focus) -> None:
         self._restart_blink()
-        if self.select_on_focus:
+        if self.select_on_focus and not event.from_app_focus:
             self.selection = Selection(0, len(self.value))
         self.app.cursor_position = self.cursor_screen_offset
         self._suggestion = ""

tests/input/test_select_on_focus.py

@@ -0,0 +1,30 @@
+"""The standard path of selecting text on focus is well covered by snapshot tests."""
+
+from textual import events
+from textual.app import App, ComposeResult
+from textual.widgets import Input
+from textual.widgets.input import Selection
+
+
+class InputApp(App[None]):
+    """An app with an input widget."""
+
+    def compose(self) -> ComposeResult:
+        yield Input("Hello, world!")
+
+
+async def test_focus_from_app_focus_does_not_select():
+    """When an Input has focused and the *app* is blurred and then focused (e.g. by pressing
+    alt+tab or focusing another terminal pane), then the content of the Input should not be
+    fully selected when `Input.select_on_focus=True`.
+    """
+    async with InputApp().run_test() as pilot:
+        input_widget = pilot.app.query_one(Input)
+        input_widget.focus()
+        input_widget.selection = Selection.cursor(0)
+        assert input_widget.selection == Selection.cursor(0)
+        pilot.app.post_message(events.AppBlur())
+        await pilot.pause()
+        pilot.app.post_message(events.AppFocus())
+        await pilot.pause()
+        assert input_widget.selection == Selection.cursor(0)