Move aliasing/normalisation logic into Key

src/textual/events.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Awaitable, Callable, Type, TypeVar
+from typing import TYPE_CHECKING, Awaitable, Callable, Type, TypeVar, Iterable
 
 import rich.repr
 from rich.style import Style
 
 from ._types import MessageTarget
 from .geometry import Offset, Size
+from .keys import _get_key_aliases
 from .message import Message
 
 MouseEventT = TypeVar("MouseEventT", bound="MouseEvent")
@@ -209,7 +210,13 @@ class Key(InputEvent):
     @property
     def key_name(self) -> str | None:
         """Name of a key suitable for use as a Python identifier."""
-        return self.key.replace("+", "_")
+        return _normalize_key(self.key)
+
+    @property
+    def key_aliases(self) -> Iterable[str]:
+        """Get the aliases for the key, including the key itself"""
+        for alias in _get_key_aliases(self.key):
+            yield _normalize_key(alias)
 
     @property
     def is_printable(self) -> bool:
@@ -222,6 +229,11 @@ class Key(InputEvent):
         return False if self.char is None else self.char.isprintable()
 
 
+def _normalize_key(key: str) -> str:
+    """Convert the key string to a name suitable for use as a Python identifier."""
+    return key.replace("+", "_")
+
+
 @rich.repr.auto
 class MouseEvent(InputEvent, bubble=True):
     """Sent in response to a mouse event.

src/textual/message_pump.py

@@ -548,11 +548,6 @@ class MessagePump(metaclass=MessagePumpMeta):
             private_handler_name = f"_key_{key}"
             private_handler = getattr(pump, private_handler_name, None)
 
-            if public_handler and private_handler:
-                _raise_duplicate_key_handlers_error(
-                    key, public_handler_name, private_handler_name
-                )
-
             return public_handler or private_handler
 
         invoked_method = None
@@ -560,9 +555,8 @@ class MessagePump(metaclass=MessagePumpMeta):
         if not key_name:
             return False
 
-        key_aliases = _get_key_aliases(event.key)
-        for key_alias in key_aliases:
-            key_method = get_key_handler(self, key_alias.replace("+", "_"))
+        for key_alias in event.key_aliases:
+            key_method = get_key_handler(self, key_alias)
             if key_method is not None:
                 if invoked_method:
                     _raise_duplicate_key_handlers_error(

tests/test_message_pump.py

@@ -47,14 +47,6 @@ class DuplicateHandlersWidget(Widget):
         self.called_by = self.key_ctrl_i
 
 
-async def test_dispatch_key_raises_when_public_and_private_handlers():
-    """When both a public and private handler exists for one key, we fail fast via exception."""
-    widget = DuplicateHandlersWidget()
-    with pytest.raises(DuplicateKeyHandlers):
-        await widget.dispatch_key(Key(widget, key="x", char="x"))
-    assert widget.called_by is None
-
-
 async def test_dispatch_key_raises_when_conflicting_handler_aliases():
     """If you've got a handler for e.g. ctrl+i and a handler for tab, that's probably a mistake.
     In the terminal, they're the same thing, so we fail fast via exception here."""