Keep arrow keys in active text fields (#132)

tests/controller_focus_presentation_validation.gd

@@ -198,6 +198,40 @@ func _run() -> void:
 		standard_button.get_theme_stylebox("hover") == old_hover_style,
 		"mouse hover styling was not restored after controller use",
 	)
+	var text_entry := LineEdit.new()
+	text_entry.position = Vector2(520.0, 60.0)
+	text_entry.size = Vector2(220.0, 48.0)
+	text_entry.text = "editable text"
+	stage.add_child(text_entry)
+	standard_button.grab_focus()
+	await process_frame
+	presentation.call("_neutralize_current_navigation_focus")
+	text_entry.grab_focus()
+	await process_frame
+	_expect(
+		presentation.get("_neutral_focus_seed") == null,
+		"entering a text field leaves the prior menu focus seed armed",
+	)
+	for keycode: Key in [KEY_LEFT, KEY_RIGHT, KEY_UP, KEY_DOWN]:
+		var arrow_key := InputEventKey.new()
+		arrow_key.keycode = keycode
+		arrow_key.physical_keycode = keycode
+		arrow_key.pressed = true
+		presentation._input(arrow_key)
+		_expect(
+			root.gui_get_focus_owner() == text_entry,
+			"arrow key %s pulled focus out of an active text field" % keycode,
+		)
+	var modified_arrow := InputEventKey.new()
+	modified_arrow.keycode = KEY_LEFT
+	modified_arrow.physical_keycode = KEY_LEFT
+	modified_arrow.shift_pressed = true
+	modified_arrow.pressed = true
+	presentation._input(modified_arrow)
+	_expect(
+		root.gui_get_focus_owner() == text_entry,
+		"a modified arrow pulled focus out of an active text field",
+	)
 	var item_list := ItemList.new()
 	item_list.position = Vector2(80.0, 160.0)
 	item_list.size = Vector2(240.0, 150.0)

ui/controller_focus_presentation.gd

@@ -86,6 +86,15 @@ func _input(event: InputEvent) -> void:
 		event is InputEventJoypadButton or event is InputEventJoypadMotion
 	):
 		return
+	# Physical keyboard arrows belong to an active text editor. A mouse click can
+	# leave the previously focused menu button cached as the neutral controller
+	# seed; restoring that seed here would pull focus out of the editor before
+	# LineEdit/TextEdit can move its caret or selection.
+	if _keyboard_direction_belongs_to_text_entry(event):
+		_navigation_focus_active = false
+		_neutral_focus_seed = null
+		_set_controller_active(false)
+		return
 	var directional_navigation: bool = _is_directional_navigation(event)
 	if directional_navigation:
 		_directional_input_generation += 1
@@ -217,6 +226,11 @@ func _on_focus_changed(control: Control) -> void:
 	if _directional_input_in_flight and _is_navigation_focus(control):
 		_navigation_focus_active = true
 		_neutral_focus_seed = null
+	elif not _is_navigation_focus(control):
+		# Text entry supersedes any button remembered before the field was clicked.
+		# Keeping that seed would make the next keyboard arrow restore the button.
+		_navigation_focus_active = false
+		_neutral_focus_seed = null
 	elif not _navigation_focus_active and _is_navigation_focus(control):
 		_capture_neutral_focus_seed(control)
 		return
@@ -261,6 +275,28 @@ func _is_directional_navigation(event: InputEvent) -> bool:
 	)
 
 
+func _keyboard_direction_belongs_to_text_entry(event: InputEvent) -> bool:
+	var key_event := event as InputEventKey
+	if key_event == null or not key_event.pressed:
+		return false
+	var focus_owner: Control = _active_focus_owner()
+	if not (focus_owner is LineEdit or focus_owner is TextEdit):
+		return false
+	# Check the keycodes directly as well as the built-in actions so modified
+	# editing gestures such as Shift+Left and Ctrl+Right cannot be mistaken for
+	# menu navigation when action matching requires exact modifier parity.
+	if key_event.keycode in [KEY_LEFT, KEY_RIGHT, KEY_UP, KEY_DOWN]:
+		return true
+	if key_event.physical_keycode in [KEY_LEFT, KEY_RIGHT, KEY_UP, KEY_DOWN]:
+		return true
+	return (
+		event.is_action_pressed(&"ui_left")
+		or event.is_action_pressed(&"ui_right")
+		or event.is_action_pressed(&"ui_up")
+		or event.is_action_pressed(&"ui_down")
+	)
+
+
 func _is_navigation_focus(control: Control) -> bool:
 	# Text entry is an explicit interaction rather than menu navigation. It must
 	# retain direct focus for typing, including Chat and dialog fields.