fix(masked input): fix bindings to move and select

Fix bindings like `shift+right` that should move the cursor and select
not selecting text in `MaskedInput`.

Author: TomJGooding

src/textual/widgets/_masked_input.py

@@ -18,7 +18,7 @@
 
 from textual.reactive import Reactive, var
 from textual.validation import ValidationResult, Validator
-from textual.widgets._input import Input
+from textual.widgets._input import Input, Selection
 
 InputValidationOn = Literal["blur", "changed", "submitted"]
 """Possible messages that trigger input validation."""
@@ -703,17 +703,31 @@ def action_cursor_left(self, select: bool = False) -> None:
         Args:
             select: If `True`, select the text to the left of the cursor.
         """
+        start, end = self.selection
         cursor_position = self._template.move_cursor(-1)
-        self.cursor_position = cursor_position
+        if select:
+            self.selection = Selection(start, cursor_position)
+        else:
+            if self.selection.is_empty:
+                self.cursor_position = cursor_position
+            else:
+                self.cursor_position = min(start, end)
 
     def action_cursor_right(self, select: bool = False) -> None:
         """Move the cursor one position to the right; separators are skipped.
 
         Args:
             select: If `True`, select the text to the right of the cursor.
         """
+        start, end = self.selection
         cursor_position = self._template.move_cursor(1)
-        self.cursor_position = cursor_position
+        if select:
+            self.selection = Selection(start, cursor_position)
+        else:
+            if self.selection.is_empty:
+                self.cursor_position = cursor_position
+            else:
+                self.cursor_position = max(start, end)
 
     def action_home(self, select: bool = False) -> None:
         """Move the cursor to the start of the input.
@@ -722,7 +736,10 @@ def action_home(self, select: bool = False) -> None:
             select: If `True`, select the text between the old and new cursor positions.
         """
         cursor_position = self._template.move_cursor(-len(self.template))
-        self.cursor_position = cursor_position
+        if select:
+            self.selection = Selection(self.cursor_position, cursor_position)
+        else:
+            self.cursor_position = cursor_position
 
     def action_cursor_left_word(self, select: bool = False) -> None:
         """Move the cursor left next to the previous separator. If no previous
@@ -732,12 +749,22 @@ def action_cursor_left_word(self, select: bool = False) -> None:
             select: If `True`, select the text between the old and new cursor positions.
         """
         if self._template.at_separator(self.cursor_position - 1):
-            position = self._template.prev_separator_position(self.cursor_position - 1)
+            separator_position = self._template.prev_separator_position(
+                self.cursor_position - 1
+            )
         else:
-            position = self._template.prev_separator_position()
-        if position:
-            position += 1
-        self.cursor_position = position or 0
+            separator_position = self._template.prev_separator_position()
+
+        if separator_position is None:
+            cursor_position = 0
+        else:
+            cursor_position = separator_position + 1
+
+        if select:
+            start, _ = self.selection
+            self.selection = Selection(start, cursor_position)
+        else:
+            self.cursor_position = cursor_position
 
     def action_cursor_right_word(self, select: bool = False) -> None:
         """Move the cursor right next to the next separator. If no next
@@ -746,11 +773,17 @@ def action_cursor_right_word(self, select: bool = False) -> None:
         Args:
             select: If `True`, select the text between the old and new cursor positions.
         """
-        position = self._template.next_separator_position()
-        if position is None:
-            self.cursor_position = len(self._template.mask)
+        separator_position = self._template.next_separator_position()
+        if separator_position is None:
+            cursor_position = len(self._template.mask)
         else:
-            self.cursor_position = position + 1
+            cursor_position = separator_position + 1
+
+        if select:
+            start, _ = self.selection
+            self.selection = Selection(start, cursor_position)
+        else:
+            self.cursor_position = cursor_position
 
     def action_delete_right(self) -> None:
         """Delete one character at the current cursor position."""

tests/test_masked_input.py

@@ -323,3 +323,41 @@ async def test_replace_selection_with_invalid_value():
         assert input.selection == (0, len(input.value))  # Sanity check
         await pilot.press("a")
         assert input.value == "2025-12"
+
+
+async def test_movement_actions_with_select():
+    app = MaskedInputApp(
+        template=">NNNNN-NNNNN-NNNNN-NNNNN;_",
+        value="ABCDE-FGHIJ-KLMNO-PQRST",
+        select_on_focus=False,
+    )
+    async with app.run_test():
+        input = app.query_one(MaskedInput)
+
+        input.action_home(select=True)
+        assert input.selection == (len(input.value), 0)
+
+        input.action_cursor_left()
+        assert input.selection.is_empty
+        assert input.cursor_position == 0
+
+        input.action_cursor_right_word(select=True)
+        assert input.selection == (0, 6)
+
+        input.action_cursor_right()
+        assert input.selection.is_empty
+        assert input.cursor_position == 6
+
+        input.action_cursor_left(select=True)
+        assert input.selection == (6, 4)
+
+        input.action_cursor_left()
+        input.action_cursor_right(select=True)
+        assert input.selection == (4, 6)
+
+        input.action_end(select=True)
+        assert input.selection == (6, len(input.value))
+
+        input.action_cursor_right()
+        input.action_cursor_left_word(select=True)
+        assert input.selection == (len(input.value), 18)