Make mypy happy

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Widget scrolling methods (such as `Widget.scroll_home` and `Widget.scroll_end`) now perform the scroll after the next refresh https://github.com/Textualize/textual/issues/1774
+- Buttons no longer accept arbitrary renderables https://github.com/Textualize/textual/issues/1870
 
 ### Fixed
 

mypy.ini

@@ -14,3 +14,7 @@ ignore_missing_imports = True
 
 [mypy-ipywidgets.*]
 ignore_missing_imports = True
+
+[mypy-uvloop.*]
+# Ignore missing imports for optional library that isn't listed as a dependency.
+ignore_missing_imports = True

src/textual/__init__.py

@@ -64,7 +64,10 @@ def __call__(self, *args: object, **kwargs) -> None:
         if app.devtools is None or not app.devtools.is_connected:
             return
 
-        previous_frame = inspect.currentframe().f_back
+        current_frame = inspect.currentframe()
+        assert current_frame is not None
+        previous_frame = current_frame.f_back
+        assert previous_frame is not None
         caller = inspect.getframeinfo(previous_frame)
 
         _log = self._log or app._log

src/textual/_callback.py

@@ -58,6 +58,7 @@ async def invoke(callback: Callable, *params: object) -> Any:
         # In debug mode we will warn about callbacks that may be stuck
         def log_slow() -> None:
             """Log a message regarding a slow callback."""
+            assert app is not None
             app.log.warning(
                 f"Callback {callback} is still pending after {INVOKE_TIMEOUT_WARNING} seconds"
             )

src/textual/_compositor.py

@@ -14,7 +14,7 @@
 from __future__ import annotations
 
 from operator import itemgetter
-from typing import TYPE_CHECKING, Iterable, NamedTuple, cast
+from typing import TYPE_CHECKING, Callable, Iterable, NamedTuple, cast
 
 import rich.repr
 from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
@@ -45,12 +45,23 @@ class ReflowResult(NamedTuple):
 class MapGeometry(NamedTuple):
     """Defines the absolute location of a Widget."""
 
-    region: Region  # The (screen) region occupied by the widget
-    order: tuple[tuple[int, ...], ...]  # A tuple of ints defining the painting order
-    clip: Region  # A region to clip the widget by (if a Widget is within a container)
-    virtual_size: Size  # The virtual size  (scrollable region) of a widget if it is a container
-    container_size: Size  # The container size (area not occupied by scrollbars)
-    virtual_region: Region  # The region relative to the container (but not necessarily visible)
+    region: Region
+    """The (screen) region occupied by the widget."""
+    order: tuple[tuple[int, int, int], ...]
+    """Tuple of tuples defining the painting order of the widget.
+
+    Each successive triple represents painting order information with regards to
+    ancestors in the DOM hierarchy and the last triple provides painting order
+    information for this specific widget.
+    """
+    clip: Region
+    """A region to clip the widget by (if a Widget is within a container)."""
+    virtual_size: Size
+    """The virtual size (scrollable region) of a widget if it is a container."""
+    container_size: Size
+    """The container size (area not occupied by scrollbars)."""
+    virtual_region: Region
+    """The region relative to the container (but not necessarily visible)."""
 
     @property
     def visible_region(self) -> Region:
@@ -419,19 +430,23 @@ def add_widget(
             widget: Widget,
             virtual_region: Region,
             region: Region,
-            order: tuple[tuple[int, ...], ...],
+            order: tuple[tuple[int, int, int], ...],
             layer_order: int,
             clip: Region,
             visible: bool,
-            _MapGeometry=MapGeometry,
+            _MapGeometry: type[MapGeometry] = MapGeometry,
         ) -> None:
             """Called recursively to place a widget and its children in the map.
 
             Args:
                 widget: The widget to add.
+                virtual_region: The Widget region relative to it's container.
                 region: The region the widget will occupy.
-                order: A tuple of ints to define the order.
+                order: Painting order information.
+                layer_order: The order of the widget in its layer.
                 clip: The clipping region (i.e. the viewport which contains it).
+                visible: Whether the widget should be visible by default.
+                    This may be overriden by the CSS rule `visibility`.
             """
             visibility = widget.styles.get_rule("visibility")
             if visibility is not None:
@@ -501,11 +516,12 @@ def add_widget(
                             )
                             widget_region = sub_region + placement_scroll_offset
 
-                        widget_order = (
-                            *order,
-                            get_layer_index(sub_widget.layer, 0),
-                            z,
-                            layer_order,
+                        widget_order = order + (
+                            (
+                                get_layer_index(sub_widget.layer, 0),
+                                z,
+                                layer_order,
+                            ),
                         )
 
                         add_widget(
@@ -560,7 +576,7 @@ def add_widget(
             root,
             size.region,
             size.region,
-            ((0,),),
+            ((0, 0, 0),),
             layer_order,
             size.region,
             True,
@@ -818,11 +834,8 @@ def render(self, full: bool = False) -> RenderableType | None:
         # Maps each cut on to a list of segments
         cuts = self.cuts
 
-        # dict.fromkeys is a callable which takes a list of ints returns a dict which maps ints on to a list of Segments or None.
-        fromkeys = cast(
-            "Callable[[list[int]], dict[int, list[Segment] | None]]", dict.fromkeys
-        )
-        # A mapping of cut index to a list of segments for each line
+        # dict.fromkeys is a callable which takes a list of ints returns a dict which maps ints onto a Segment or None.
+        fromkeys = cast("Callable[[list[int]], dict[int, Strip | None]]", dict.fromkeys)
         chops: list[dict[int, Strip | None]]
         chops = [fromkeys(cut_set[:-1]) for cut_set in cuts]
 

src/textual/_doc.py

@@ -4,7 +4,7 @@
 import os
 import shlex
 from pathlib import Path
-from typing import Iterable
+from typing import Iterable, cast
 
 from textual._import_app import import_app
 from textual.app import App
@@ -45,6 +45,7 @@ def format_svg(source, language, css_class, options, md, attrs, **kwargs) -> str
         import traceback
 
         traceback.print_exception(error)
+        return ""
 
 
 def take_svg_screenshot(
@@ -82,6 +83,7 @@ def get_cache_key(app: App) -> str:
         hash = hashlib.md5()
         file_paths = [app_path] + app.css_path
         for path in file_paths:
+            assert path is not None
             with open(path, "rb") as source_file:
                 hash.update(source_file.read())
         hash.update(f"{press}-{title}-{terminal_size}".encode("utf-8"))
@@ -105,10 +107,13 @@ async def auto_pilot(pilot: Pilot) -> None:
 
         app.exit(svg)
 
-    svg = app.run(
-        headless=True,
-        auto_pilot=auto_pilot,
-        size=terminal_size,
+    svg = cast(
+        str,
+        app.run(
+            headless=True,
+            auto_pilot=auto_pilot,
+            size=terminal_size,
+        ),
     )
 
     if app_path is not None:

src/textual/_styles_cache.py

@@ -18,7 +18,7 @@
 from .strip import Strip
 
 if TYPE_CHECKING:
-    from typing import TypeAlias
+    from typing_extensions import TypeAlias
 
     from .css.styles import StylesBase
     from .widget import Widget

src/textual/_xterm_parser.py

@@ -200,8 +200,8 @@ def reissue_sequence_as_keys(reissue_sequence: str) -> None:
                     if not bracketed_paste:
                         # Was it a pressed key event that we received?
                         key_events = list(sequence_to_key_events(sequence))
-                        for event in key_events:
-                            on_token(event)
+                        for key_event in key_events:
+                            on_token(key_event)
                         if key_events:
                             break
                         # Or a mouse event?

src/textual/actions.py

@@ -3,6 +3,11 @@
 import ast
 import re
 
+from typing_extensions import Any, TypeAlias
+
+ActionParseResult: TypeAlias = "tuple[str, tuple[Any, ...]]"
+"""An action is its name and the arbitrary tuple of its parameters."""
+
 
 class SkipAction(Exception):
     """Raise in an action to skip the action (and allow any parent bindings to run)."""
@@ -15,7 +20,7 @@ class ActionError(Exception):
 re_action_params = re.compile(r"([\w\.]+)(\(.*?\))")
 
 
-def parse(action: str) -> tuple[str, tuple[object, ...]]:
+def parse(action: str) -> ActionParseResult:
     """Parses an action string.
 
     Args:

src/textual/app.py

@@ -57,7 +57,7 @@
 from ._event_broker import NoHandler, extract_handler_actions
 from ._path import _make_path_object_relative
 from ._wait import wait_for_idle
-from .actions import SkipAction
+from .actions import ActionParseResult, SkipAction
 from .await_remove import AwaitRemove
 from .binding import Binding, Bindings
 from .css.query import NoMatches
@@ -645,7 +645,7 @@ def _log(
         self,
         group: LogGroup,
         verbosity: LogVerbosity,
-        _textual_calling_frame: inspect.FrameInfo,
+        _textual_calling_frame: inspect.Traceback,
         *objects: Any,
         **kwargs,
     ) -> None:
@@ -1605,9 +1605,8 @@ async def invoke_ready_callback() -> None:
                                 with redirect_stdout(redirector):  # type: ignore
                                     await run_process_messages()
                         else:
-                            null_file = _NullFile()
-                            with redirect_stderr(null_file):
-                                with redirect_stdout(null_file):
+                            with redirect_stderr(None):
+                                with redirect_stdout(None):
                                     await run_process_messages()
 
                 finally:
@@ -1732,16 +1731,17 @@ def _register(
         if not widgets:
             return []
 
-        new_widgets = list(widgets)
-
+        widget_list: Iterable[Widget]
         if before is not None or after is not None:
             # There's a before or after, which means there's going to be an
             # insertion, so make it easier to get the new things in the
             # correct order.
-            new_widgets = reversed(new_widgets)
+            widget_list = reversed(widgets)
+        else:
+            widget_list = widgets
 
         apply_stylesheet = self.stylesheet.apply
-        for widget in new_widgets:
+        for widget in widget_list:
             if not isinstance(widget, Widget):
                 raise AppError(f"Can't register {widget!r}; expected a Widget instance")
             if widget not in self._registry:
@@ -1798,14 +1798,14 @@ def is_mounted(self, widget: Widget) -> bool:
     async def _close_all(self) -> None:
         """Close all message pumps."""
 
-        # Close all screens on the stack
-        for screen in reversed(self._screen_stack):
-            if screen._running:
-                await self._prune_node(screen)
+        # Close all screens on the stack.
+        for stack_screen in reversed(self._screen_stack):
+            if stack_screen._running:
+                await self._prune_node(stack_screen)
 
         self._screen_stack.clear()
 
-        # Close pre-defined screens
+        # Close pre-defined screens.
         for screen in self.SCREENS.values():
             if isinstance(screen, Screen) and screen._running:
                 await self._prune_node(screen)
@@ -1971,7 +1971,7 @@ async def on_event(self, event: events.Event) -> None:
 
     async def action(
         self,
-        action: str | tuple[str, tuple[str, ...]],
+        action: str | ActionParseResult,
         default_namespace: object | None = None,
     ) -> bool:
         """Perform an action.
@@ -2069,7 +2069,7 @@ async def _broker_event(
         else:
             event.stop()
         if isinstance(action, (str, tuple)):
-            await self.action(action, default_namespace=default_namespace)
+            await self.action(action, default_namespace=default_namespace)  # type: ignore[arg-type]
         elif callable(action):
             await action()
         else:
@@ -2339,20 +2339,23 @@ def _end_update(self) -> None:
 
 
 def _init_uvloop() -> None:
-    """
-    Import and install the `uvloop` asyncio policy, if available.
+    """Import and install the `uvloop` asyncio policy, if available.
+
     This is done only once, even if the function is called multiple times.
+
+    This is provided as a nicety for users that have `uvloop` installed independently
+    of Textual, as `uvloop` is not listed as a Textual dependency.
     """
     global _uvloop_init_done
 
     if _uvloop_init_done:
         return
 
     try:
-        import uvloop
+        import uvloop  # type: ignore[reportMissingImports]
     except ImportError:
         pass
     else:
-        uvloop.install()
+        uvloop.install()  # type: ignore[reportUnknownMemberType]
 
     _uvloop_init_done = True

src/textual/cli/previews/easing.py

@@ -92,6 +92,7 @@ def _animation_complete():
         target_position = (
             END_POSITION if self.position == START_POSITION else START_POSITION
         )
+        assert event.button.id is not None  # Should be set to an easing function str.
         self.animate(
             "position",
             value=target_position,
@@ -106,7 +107,7 @@ def watch_position(self, value: int):
         self.opacity_widget.styles.opacity = 1 - value / END_POSITION
 
     def on_input_changed(self, event: Input.Changed):
-        if event.sender.id == "duration-input":
+        if event.input.id == "duration-input":
             new_duration = _try_float(event.value)
             if new_duration is not None:
                 self.duration = new_duration

src/textual/css/_style_properties.py

@@ -528,8 +528,8 @@ def __set__(self, obj: StylesBase, spacing: SpacingDimensions | None):
                 string (e.g. ``"blue on #f0f0f0"``).
 
         Raises:
-            ValueError: When the value is malformed, e.g. a ``tuple`` with a length that is
-                not 1, 2, or 4.
+            ValueError: When the value is malformed,
+                e.g. a ``tuple`` with a length that is not 1, 2, or 4.
         """
         _rich_traceback_omit = True
         if spacing is None:
@@ -543,7 +543,9 @@ def __set__(self, obj: StylesBase, spacing: SpacingDimensions | None):
                     str(error),
                     help_text=spacing_wrong_number_of_values_help_text(
                         property_name=self.name,
-                        num_values_supplied=len(spacing),
+                        num_values_supplied=(
+                            1 if isinstance(spacing, int) else len(spacing)
+                        ),
                         context="inline",
                     ),
                 )