Merge pull request #6374 from Textualize/blank-to-null

change sentinal name

Author: willmcgugan

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - It is no longer a NOOP and warning to dismiss a non-active screen. The dismiss will still work, but the screen may not update if the current mode is not active. https://github.com/Textualize/textual/pull/6362
 - Added 50ms delay when switching screens to allow state to udpate and prevent janky flash of old content https://github.com/Textualize/textual/pull/6362
+- Breaking change: Changed `Select.BLANK` to `Select.NULL` to avoid clash with newer `Widget.BLANK` Classvar https://github.com/Textualize/textual/pull/6374
 
 ## [7.5.0] - 2026-01-30
 

docs/widgets/select.md

@@ -89,7 +89,7 @@ The following example presents a `Select` created using the `from_values` class
 ## Blank state
 
 The `Select` widget has an option `allow_blank` for its constructor.
-If set to `True`, the widget may be in a state where there is no selection, in which case its value will be the special constant [`Select.BLANK`][textual.widgets.Select.BLANK].
+If set to `True`, the widget may be in a state where there is no selection, in which case its value will be the special constant [`Select.NULL`][textual.widgets.Select.NULL].
 The auxiliary methods [`Select.is_blank`][textual.widgets.Select.is_blank] and [`Select.clear`][textual.widgets.Select.clear] provide a convenient way to check if the widget is in this state and to set this state, respectively.
 
 ## Type to search
@@ -98,10 +98,10 @@ The `Select` widget has a `type_to_search` attribute which allows you to type to
 
 ## Reactive Attributes
 
-| Name       | Type                           | Default                                        | Description                         |
-|------------|--------------------------------|------------------------------------------------|-------------------------------------|
-| `expanded` | `bool`                         | `False`                                        | True to expand the options overlay. |
-| `value`    | `SelectType` \| `_NoSelection` | [`Select.BLANK`][textual.widgets.Select.BLANK] | Current value of the Select.        |
+| Name       | Type                           | Default                                      | Description                         |
+| ---------- | ------------------------------ | -------------------------------------------- | ----------------------------------- |
+| `expanded` | `bool`                         | `False`                                      | True to expand the options overlay. |
+| `value`    | `SelectType` \| `_NoSelection` | [`Select.NULL`][textual.widgets.Select.NULL] | Current value of the Select.        |
 
 ## Messages
 

src/textual/widgets/_select.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, Generic, Hashable, Iterable, TypeVar, Union
+from typing import TYPE_CHECKING, Generic, Hashable, Iterable, TypeVar
 
 import rich.repr
 from rich.console import RenderableType
@@ -28,13 +28,13 @@ class NonSelectableStatic(Static):
 
 
 class NoSelection:
-    """Used by the `Select` widget to flag the unselected state. See [`Select.BLANK`][textual.widgets.Select.BLANK]."""
+    """Used by the `Select` widget to flag the unselected state. See [`Select.NULL`][textual.widgets.Select.NULL]."""
 
     def __repr__(self) -> str:
-        return "Select.BLANK"
+        return "Select.NULL"
 
 
-BLANK = NoSelection()
+NULL = NoSelection()
 
 
 class InvalidSelectValueError(Exception):
@@ -240,7 +240,7 @@ def __init__(self, placeholder: str) -> None:
         """
         super().__init__()
         self.placeholder = placeholder
-        self.label: RenderableType | NoSelection = Select.BLANK
+        self.label: RenderableType | NoSelection = Select.NULL
 
     def update(self, label: RenderableType | NoSelection) -> None:
         """Update the content in the widget.
@@ -249,7 +249,7 @@ def update(self, label: RenderableType | NoSelection) -> None:
             label: A renderable to display, or `None` for the placeholder.
         """
         self.label = label
-        self.has_value = label is not Select.BLANK
+        self.has_value = label is not Select.NULL
         self.query_one("#label", Static).update(
             self.placeholder if isinstance(label, NoSelection) else label
         )
@@ -283,7 +283,7 @@ class Select(Generic[SelectType], Vertical, can_focus=True):
     When activated with ++enter++ the widget displays an overlay with a list of all possible options.
     """
 
-    BLANK = BLANK
+    NULL = NULL
     """Constant to flag that the widget has no selection."""
 
     BINDINGS = [
@@ -356,12 +356,10 @@ class Select(Generic[SelectType], Vertical, can_focus=True):
     """True to show the overlay, otherwise False."""
     prompt: var[str] = var[str]("Select")
     """The prompt to show when no value is selected."""
-    value: var[SelectType | NoSelection] = var[Union[SelectType, NoSelection]](
-        BLANK, init=False
-    )
+    value: var[SelectType | NoSelection] = var(NULL, init=False)
     """The value of the selection.
 
-    If the widget has no selection, its value will be [`Select.BLANK`][textual.widgets.Select.BLANK].
+    If the widget has no selection, its value will be [`Select.NULL`][textual.widgets.Select.NULL].
     Setting this to an illegal value will raise a [`InvalidSelectValueError`][textual.widgets.select.InvalidSelectValueError]
     exception.
     """
@@ -403,7 +401,7 @@ def __init__(
         *,
         prompt: str = "Select",
         allow_blank: bool = True,
-        value: SelectType | NoSelection = BLANK,
+        value: SelectType | NoSelection = NULL,
         type_to_search: bool = True,
         name: str | None = None,
         id: str | None = None,
@@ -420,7 +418,7 @@ def __init__(
             prompt: Text to show in the control when no option is selected.
             allow_blank: Enables or disables the ability to have the widget in a state
                 with no selection made, in which case its value is set to the constant
-                [`Select.BLANK`][textual.widgets.Select.BLANK].
+                [`Select.NULL`][textual.widgets.Select.NULL].
             value: Initial value selected. Should be one of the values in `options`.
                 If no initial value is set and `allow_blank` is `False`, the widget
                 will auto-select the first available option.
@@ -452,7 +450,7 @@ def from_values(
         *,
         prompt: str = "Select",
         allow_blank: bool = True,
-        value: SelectType | NoSelection = BLANK,
+        value: SelectType | NoSelection = NULL,
         type_to_search: bool = True,
         name: str | None = None,
         id: str | None = None,
@@ -470,7 +468,7 @@ def from_values(
             prompt: Text to show in the control when no option is selected.
             allow_blank: Enables or disables the ability to have the widget in a state
                 with no selection made, in which case its value is set to the constant
-                [`Select.BLANK`][textual.widgets.Select.BLANK].
+                [`Select.NULL`][textual.widgets.Select.NULL].
             value: Initial value selected. Should be one of the values in `values`.
                 If no initial value is set and `allow_blank` is `False`, the widget
                 will auto-select the first available value.
@@ -522,7 +520,7 @@ def _setup_variables_for_options(
         """
         self._options: list[tuple[RenderableType, SelectType | NoSelection]] = []
         if self._allow_blank:
-            self._options.append(("", self.BLANK))
+            self._options.append(("", self.NULL))
         self._options.extend(options)
 
         if not self._options:
@@ -539,7 +537,7 @@ def _setup_options_renderables(self) -> None:
         options: list[Option] = [
             (
                 Option(Text(self.prompt, style="dim"))
-                if value == self.BLANK
+                if value == self.NULL
                 else Option(prompt)
             )
             for prompt, value in self._options
@@ -549,9 +547,9 @@ def _setup_options_renderables(self) -> None:
         option_list.clear_options()
         option_list.add_options(options)
 
-    def _init_selected_option(self, hint: SelectType | NoSelection = BLANK) -> None:
+    def _init_selected_option(self, hint: SelectType | NoSelection = NULL) -> None:
         """Initialises the selected option for the `Select`."""
-        if hint == self.BLANK and not self._allow_blank:
+        if hint == self.NULL and not self._allow_blank:
             hint = self._options[0][1]
         self.value = hint
 
@@ -604,8 +602,8 @@ def _watch_value(self, value: SelectType | NoSelection) -> None:
         except NoMatches:
             pass
         else:
-            if value == self.BLANK:
-                select_current.update(self.BLANK)
+            if value == self.NULL:
+                select_current.update(self.NULL)
             else:
                 for index, (prompt, _value) in enumerate(self._options):
                     if _value == value:
@@ -637,7 +635,7 @@ def _watch_expanded(self, expanded: bool) -> None:
         self.set_class(expanded, "-expanded")
         if expanded:
             overlay.focus(scroll_visible=False)
-            if self.value is self.BLANK:
+            if self.value is self.NULL:
                 overlay.select(None)
                 self.query_one(SelectCurrent).has_value = False
             else:
@@ -690,7 +688,7 @@ def is_blank(self) -> bool:
         Returns:
             True if the selection is blank, False otherwise.
         """
-        return self.value == self.BLANK
+        return self.value == self.NULL
 
     def clear(self) -> None:
         """Clear the selection if `allow_blank` is `True`.
@@ -699,7 +697,7 @@ def clear(self) -> None:
             InvalidSelectValueError: If `allow_blank` is set to `False`.
         """
         try:
-            self.value = self.BLANK
+            self.value = self.NULL
         except InvalidSelectValueError:
             raise InvalidSelectValueError(
                 "Can't clear selection if allow_blank is set to False."
@@ -712,7 +710,7 @@ def _watch_prompt(self, prompt: str) -> None:
         select_current.placeholder = prompt
         if not self._allow_blank:
             return
-        if self.value == self.BLANK:
-            select_current.update(self.BLANK)
+        if self.value == self.NULL:
+            select_current.update(self.NULL)
         option_list = self.query_one(SelectOverlay)
         option_list.replace_option_prompt_at_index(0, Text(prompt, style="dim"))

src/textual/widgets/select.py

@@ -1,8 +1,8 @@
 from textual.widgets._select import (
-    BLANK,
+    NULL,
     EmptySelectError,
     InvalidSelectValueError,
     NoSelection,
 )
 
-__all__ = ["EmptySelectError", "InvalidSelectValueError", "NoSelection", "BLANK"]
+__all__ = ["EmptySelectError", "InvalidSelectValueError", "NoSelection", "NULL"]

tests/select/test_blank_and_clear.py

@@ -15,7 +15,7 @@ def compose(self):
     app = SelectApp()
     async with app.run_test():
         select = app.query_one(Select)
-        assert select.value == Select.BLANK
+        assert select.value == Select.NULL
         assert select.is_blank()
 
 
@@ -27,15 +27,15 @@ def compose(self):
     app = SelectApp()
     async with app.run_test():
         select = app.query_one(Select)
-        assert select.value == Select.BLANK
+        assert select.value == Select.NULL
         assert select.is_blank()
 
         select.value = 0
-        assert select.value != Select.BLANK
+        assert select.value != Select.NULL
         assert not select.is_blank()
 
-        select.value = Select.BLANK
-        assert select.value == Select.BLANK
+        select.value = Select.NULL
+        assert select.value == Select.NULL
         assert select.is_blank()
 
 
@@ -64,6 +64,7 @@ def compose(self):
         with pytest.raises(InvalidSelectValueError):
             select.clear()
 
+
 async def test_selection_is_none_with_blank():
     class SelectApp(App[None]):
         def compose(self):

tests/select/test_value.py

@@ -9,7 +9,7 @@
 
 
 class SelectApp(App[None]):
-    def __init__(self, initial_value=Select.BLANK):
+    def __init__(self, initial_value=Select.NULL):
         self.initial_value = initial_value
         super().__init__()
 
@@ -51,12 +51,12 @@ def compose(self):
 
 
 async def test_value_assign_to_blank():
-    """Setting the value to BLANK should work with default `allow_blank` value."""
+    """Setting the value to NULL should work with default `allow_blank` value."""
     app = SelectApp(1)
     async with app.run_test():
         select = app.query_one(Select)
         assert select.value == 1
-        select.value = Select.BLANK
+        select.value = Select.NULL
         assert select.is_blank()
 
 
@@ -85,7 +85,7 @@ def compose(self):
 
 
 async def test_set_value_to_blank_with_allow_blank_false():
-    """Setting the value to BLANK with allow_blank=False should raise an error."""
+    """Setting the value to NULL with allow_blank=False should raise an error."""
 
     class SelectApp(App[None]):
         def compose(self):
@@ -94,11 +94,11 @@ def compose(self):
     app = SelectApp()
     async with app.run_test():
         with pytest.raises(InvalidSelectValueError):
-            app.query_one(Select).value = Select.BLANK
+            app.query_one(Select).value = Select.NULL
 
 
 async def test_set_options_resets_value_to_blank():
-    """Resetting the options should reset the value to BLANK."""
+    """Resetting the options should reset the value to NULL."""
 
     class SelectApp(App[None]):
         def compose(self):