Allow setting of app title in constructor, fix input validation

src/textual/app.py

@@ -60,7 +60,6 @@ _ASYNCIO_GET_EVENT_LOOP_IS_DEPRECATED = sys.version_info >= (3, 10, 0)
 
 LayoutDefinition = "dict[str, Any]"
 
-
 DEFAULT_COLORS = {
     "dark": ColorSystem(
         primary="#004578",
@@ -82,7 +81,6 @@ DEFAULT_COLORS = {
     ),
 }
 
-
 ComposeResult = Iterable[Widget]
 RenderResult = RenderableType
 
@@ -178,7 +176,6 @@ class App(Generic[ReturnType], DOMNode):
         )
         self.error_console = Console(markup=False, stderr=True)
         self.driver_class = driver_class or self.get_driver_class()
-        self._title = title
         self._screen_stack: list[Screen] = []
         self._sync_available = False
 
@@ -192,9 +189,9 @@ class App(Generic[ReturnType], DOMNode):
         self._animate = self._animator.bind(self)
         self.mouse_position = Offset(0, 0)
         if title is None:
-            self._title = f"{self.__class__.__name__}"
+            self.title = f"{self.__class__.__name__}"
         else:
-            self._title = title
+            self.title = title
 
         self._logger = Logger(self._log)
 
@@ -1021,7 +1018,6 @@ class App(Generic[ReturnType], DOMNode):
 
             Reactive._initialize_object(self)
 
-            self.title = self._title
             self.stylesheet.update(self)
             self.refresh()
 

src/textual/widgets/_input.py

@@ -91,9 +91,9 @@ class Input(Widget, can_focus=True):
     COMPONENT_CLASSES = {"input--cursor", "input--placeholder"}
 
     cursor_blink = reactive(True)
-    value = reactive("", layout=True)
+    value = reactive("", layout=True, init=False)
     input_scroll_offset = reactive(0)
-    cursor_position = reactive(0)
+    cursor_position = reactive(0, init=False)
     view_position = reactive(0)
     placeholder = reactive("")
     complete = reactive("")
@@ -104,7 +104,7 @@ class Input(Widget, can_focus=True):
 
     def __init__(
         self,
-        value: str = "",
+        value: str | None = None,
         placeholder: str = "",
         highlighter: Highlighter | None = None,
         password: bool = False,
@@ -113,10 +113,12 @@ class Input(Widget, can_focus=True):
         classes: str | None = None,
     ) -> None:
         super().__init__(name=name, id=id, classes=classes)
-        self.value = value
+        if value is not None:
+            self.value = value
         self.placeholder = placeholder
         self.highlighter = highlighter
         self.password = password
+        self.view_position = 0
 
     def _position_to_cell(self, position: int) -> int:
         """Convert an index within the value to cell position."""
@@ -169,7 +171,6 @@ class Input(Widget, can_focus=True):
         return self._position_to_cell(len(self.value)) + 1
 
     def render(self) -> RenderableType:
-        self.view_position = self.view_position
         if not self.value:
             placeholder = Text(self.placeholder)
             placeholder.stylize(self.get_component_rich_style("input--placeholder"))