Infinite loop, then crash, when clicking into empty space in simple app (CSS branch)

[jeffwright13]

The code at the end of this post renders a Tab widget and has a "sunset" background. When I click into the background, the program drops to console, but does nothing for a time (and becomes unresponsive), then eventually gives me this message:
RecursionError: maximum recursion depth exceeded while calling a Python object

Console shows this traceback if I let it continue on its own:

╭────────────────────────────────────────────────────────────────────────── Traceback (most recent call last) ───────────────────────────────────────────────────────────────────────────╮
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/app.py:614 in on_event                                                                                      │
│                                                                                                                                                                                        │
│   611 │   │   │   │   │   await super().on_event(event)                                       ╭──────────────────── locals ─────────────────────╮                                      │
│   612 │   │   │   else:                                                                       │ __class__ = <class 'textual.app.App'>           │                                      │
│   613 │   │   │   │   # Forward the event to the view                                         │     event = MouseDown(x=45, y=14, button=1)     │                                      │
│ ❱ 614 │   │   │   │   await self.screen.forward_event(event)                                  │      self = TabApp(title='Textual Application') │                                      │
│   615 │   │   else:                                                                           ╰─────────────────────────────────────────────────╯                                      │
│   616 │   │   │   await super().on_event(event)                                                                                                                                        │
│   617                                                                                                                                                                                  │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/screen.py:200 in forward_event                                                                              │
│                                                                                                                                                                                        │
│   197 │   │   │   │   if isinstance(event, events.MouseDown) and widget.can_focus:            ╭──────────────────── locals ─────────────────────╮                                      │
│   198 │   │   │   │   │   await self.app.set_focus(widget)                                    │  event = MouseDown(x=45, y=14, button=1)        │                                      │
│   199 │   │   │   │   event.style = self.get_style_at(event.screen_x, event.screen_y)         │ region = Region(x=0, y=0, width=186, height=68) │                                      │
│ ❱ 200 │   │   │   │   await widget.forward_event(event.offset(-region.x, -region.y))          │   self = Screen()                               │                                      │
│   201 │   │                                                                                   │ widget = Screen()                               │                                      │
│   202 │   │   elif isinstance(event, (events.MouseScrollDown, events.MouseScrollUp)):         ╰─────────────────────────────────────────────────╯                                      │
│   203 │   │   │   try:                                                                                                                                                                 │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/screen.py:200 in forward_event
.
.
.
.
 /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/screen.py:199 in forward_event                                                                              │
│                                                                                                                                                                                        │
│   196 │   │   │   else:                                                                       ╭──────────────────── locals ─────────────────────╮                                      │
│   197 │   │   │   │   if isinstance(event, events.MouseDown) and widget.can_focus:            │  event = MouseDown(x=45, y=14, button=1)        │                                      │
│   198 │   │   │   │   │   await self.app.set_focus(widget)                                    │ region = Region(x=0, y=0, width=186, height=68) │                                      │
│ ❱ 199 │   │   │   │   event.style = self.get_style_at(event.screen_x, event.screen_y)         │   self = Screen()                               │                                      │
│   200 │   │   │   │   await widget.forward_event(event.offset(-region.x, -region.y))          │ widget = Screen()                               │                                      │
│   201 │   │                                                                                   ╰─────────────────────────────────────────────────╯                                      │
│   202 │   │   elif isinstance(event, (events.MouseScrollDown, events.MouseScrollUp)):                                                                                                  │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/screen.py:72 in get_style_at                                                                                │
│                                                                                                                                                                                        │
│    69 │   │   Returns:                                                                        ╭──── locals ─────╮                                                                      │
│    70 │   │   │   Style: Rich Style object                                                    │ self = Screen() │                                                                      │
│    71 │   │   """                                                                             │    x = 45       │                                                                      │
│ ❱  72 │   │   return self._compositor.get_style_at(x, y)                                      │    y = 14       │                                                                      │
│    73 │                                                                                       ╰─────────────────╯                                                                      │
│    74 │   def get_widget_region(self, widget: Widget) -> Region:                                                                                                                       │
│    75 │   │   """Get the screen region of a Widget.                                                                                                                                    │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/_compositor.py:320 in get_style_at                                                                          │
│                                                                                                                                                                                        │
│   317 │   │   │   Style: The Style at the cell (x, y) within the Layout                       ╭──────────────────────────────────── locals ────────────────────────────────────╮       │
│   318 │   │   """                                                                             │ self = <Compositor size=Size(width=186, height=68) widgets={Screen(), Tabs()}> │       │
│   319 │   │   try:                                                                            │    x = 45                                                                      │       │
│ ❱ 320 │   │   │   widget, region = self.get_widget_at(x, y)                                   │    y = 14                                                                      │       │
│   321 │   │   except errors.NoWidget:                                                         ╰────────────────────────────────────────────────────────────────────────────────╯       │
│   322 │   │   │   return Style.null()                                                                                                                                                  │
│   323 │   │   if widget not in self.regions:                                                                                                                                           │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/_compositor.py:304 in get_widget_at                                                                         │
│                                                                                                                                                                                        │
│   301 │   def get_widget_at(self, x: int, y: int) -> tuple[Widget, Region]:                   ╭────────────────────────────────────── locals ──────────────────────────────────────╮   │
│   302 │   │   """Get the widget under the given point or None."""                             │ contains = <function Region.contains at 0x10a2bea70>                               │   │
│   303 │   │   contains = Region.contains                                                      │     self = <Compositor size=Size(width=186, height=68) widgets={Screen(), Tabs()}> │   │
│ ❱ 304 │   │   for widget, cropped_region, region, *_ in self:                                 │        x = 45                                                                      │   │
│   305 │   │   │   if contains(cropped_region, x, y):                                          │        y = 14                                                                      │   │
│   306 │   │   │   │   return widget, region                                                   ╰────────────────────────────────────────────────────────────────────────────────────╯   │
│   307 │   │   raise errors.NoWidget(f"No widget under screen coordinate ({x}, {y})")                                                                                                   │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/_compositor.py:288 in __iter__                                                                              │
│                                                                                                                                                                                        │
│   285 │   │   for widget, (region, _order, clip, virtual_size, container_size) in layers:                                                                                              │
│   286 │   │   │   yield (                                                                                                                                                              │
│   287 │   │   │   │   widget,                                                                                                                                                          │
│ ❱ 288 │   │   │   │   intersection(region, clip),                                                                                                                                      │
│   289 │   │   │   │   region,                                                                                                                                                          │
│   290 │   │   │   │   virtual_size,                                                                                                                                                    │
│   291 │   │   │   │   container_size,                                                                                                                                                  │
│                                                                                                                                                                                        │
│ ╭───────────────────────────────────────── locals ─────────────────────────────────────────╮                                                                                           │
│ │         _order = (0, 0, 0)                                                               │                                                                                           │
│ │           clip = Region(x=0, y=0, width=186, height=68)                                  │                                                                                           │
│ │ container_size = Size(width=186, height=2)                                               │                                                                                           │
│ │   intersection = <function Region.intersection at 0x10a2bee60>                           │                                                                                           │
│ │         layers = [                                                                       │                                                                                           │
│ │                  │   (                                                                   │                                                                                           │
│ │                  │   │   Tabs(),                                                         │                                                                                           │
│ │                  │   │   RenderRegion(                                                   │                                                                                           │
│ │                  │   │   │   region=Region(x=0, y=2, width=186, height=2),               │                                                                                           │
│ │                  │   │   │   order=(0, 0, 0),                                            │                                                                                           │
│ │                  │   │   │   clip=Region(x=0, y=0, width=186, height=68),                │                                                                                           │
│ │                  │   │   │   virtual_size=Size(width=186, height=2),                     │                                                                                           │
│ │                  │   │   │   container_size=Size(width=186, height=2)                    │                                                                                           │
│ │                  │   │   )                                                               │                                                                                           │
│ │                  │   ),                                                                  │                                                                                           │
│ │                  │   (                                                                   │                                                                                           │
│ │                  │   │   Screen(),                                                       │                                                                                           │
│ │                  │   │   RenderRegion(                                                   │                                                                                           │
│ │                  │   │   │   region=Region(x=0, y=0, width=186, height=68),              │                                                                                           │
│ │                  │   │   │   order=(),                                                   │                                                                                           │
│ │                  │   │   │   clip=Region(x=0, y=0, width=186, height=68),                │                                                                                           │
│ │                  │   │   │   virtual_size=Size(width=186, height=68),                    │                                                                                           │
│ │                  │   │   │   container_size=Size(width=186, height=68)                   │                                                                                           │
│ │                  │   │   )                                                               │                                                                                           │
│ │                  │   )                                                                   │                                                                                           │
│ │                  ]                                                                       │                                                                                           │
│ │         region = Region(x=0, y=2, width=186, height=2)                                   │                                                                                           │
│ │           self = <Compositor size=Size(width=186, height=68) widgets={Screen(), Tabs()}> │                                                                                           │
│ │   virtual_size = Size(width=186, height=2)                                               │                                                                                           │
│ │         widget = Tabs()                                                                  │                                                                                           │
│ ╰──────────────────────────────────────────────────────────────────────────────────────────╯                                                                                           │
│                                                                                                                                                                                        │
│ /Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/geometry.py:473 in intersection                                                                             │
│                                                                                                                                                                                        │
│   470 │   │   rx2 = cx2 if x2 > cx2 else (cx1 if x2 < cx1 else x2)                            ╭──────────────────── locals ─────────────────────╮                                      │
│   471 │   │   ry2 = cy2 if y2 > cy2 else (cy1 if y2 < cy1 else y2)                            │    cx1 = 0                                      │                                      │
│   472 │   │                                                                                   │    cx2 = 186                                    │                                      │
│ ❱ 473 │   │   return Region(rx1, ry1, rx2 - rx1, ry2 - ry1)                                   │    cy1 = 0                                      │                                      │
│   474 │                                                                                       │    cy2 = 68                                     │                                      │
│   475 │   def union(self, region: Region) -> Region:                                          │     h1 = 2                                      │                                      │
│   476 │   │   """Get a new region that contains both regions.                                 │     h2 = 68                                     │                                      │
│                                                                                               │ region = Region(x=0, y=0, width=186, height=68) │                                      │
│                                                                                               │    rx1 = 0                                      │                                      │
│                                                                                               │    rx2 = 186                                    │                                      │
│                                                                                               │    ry1 = 2                                      │                                      │
│                                                                                               │    ry2 = 4                                      │                                      │
│                                                                                               │   self = Region(x=0, y=2, width=186, height=2)  │                                      │
│                                                                                               │     w1 = 186                                    │                                      │
│                                                                                               │     w2 = 186                                    │                                      │
│                                                                                               │     x1 = 0                                      │                                      │
│                                                                                               │     x2 = 186                                    │                                      │
│                                                                                               │     y1 = 2                                      │                                      │
│                                                                                               │     y2 = 4                                      │                                      │
│                                                                                               ╰─────────────────────────────────────────────────╯                                      │
│ <string>:1 in <lambda>                                                                                                                                                                 │
│ ╭────────────────── locals ──────────────────╮                                                                                                                                         │
│ │   _cls = <class 'textual.geometry.Region'> │                                                                                                                                         │
│ │ height = 2                                 │                                                                                                                                         │
│ │  width = 186                               │                                                                                                                                         │
│ │      x = 0                                 │                                                                                                                                         │
│ │      y = 2                                 │                                                                                                                                         │
│ ╰────────────────────────────────────────────╯                                                                                                                                         │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
RecursionError: maximum recursion depth exceeded while calling a Python object

Console displays this traceback if I hit Ctrl-C before it self-quits:

^CTraceback (most recent call last):
  File "/Users/jwr003/coding/pytest-fold/pytest_fold/tui_textual_tab.py", line 61, in <module>
    main()
  File "/Users/jwr003/coding/pytest-fold/pytest_fold/tui_textual_tab.py", line 57, in main
    TabApp().run()
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/app.py", line 244, in run
    asyncio.run(run_app())
  File "/Users/jwr003/.pyenv/versions/3.10.2/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/Users/jwr003/.pyenv/versions/3.10.2/lib/python3.10/asyncio/base_events.py", line 628, in run_until_complete
    self.run_forever()
  File "/Users/jwr003/.pyenv/versions/3.10.2/lib/python3.10/asyncio/base_events.py", line 595, in run_forever
    self._run_once()
  File "/Users/jwr003/.pyenv/versions/3.10.2/lib/python3.10/asyncio/base_events.py", line 1881, in _run_once
    handle._run()
  File "/Users/jwr003/.pyenv/versions/3.10.2/lib/python3.10/asyncio/events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/app.py", line 230, in run_app
    await app.process_messages()
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/app.py", line 440, in process_messages
    self._print_error_renderables()
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/textual/app.py", line 384, in _print_error_renderables
    self.error_console.print(renderable)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1621, in print
    extend(render(renderable, render_options))
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1263, in render
    yield from self.render(render_output, _options)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1263, in render
    yield from self.render(render_output, _options)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1259, in render
    for render_output in iter_render:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/panel.py", line 176, in __rich_console__
    lines = console.render_lines(renderable, child_options, style=style)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1294, in render_lines
    lines = list(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/segment.py", line 281, in split_and_crop_lines
    for segment in segments:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1259, in render
    for render_output in iter_render:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/padding.py", line 97, in __rich_console__
    lines = console.render_lines(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1294, in render_lines
    lines = list(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/segment.py", line 281, in split_and_crop_lines
    for segment in segments:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1263, in render
    yield from self.render(render_output, _options)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1263, in render
    yield from self.render(render_output, _options)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1259, in render
    for render_output in iter_render:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/table.py", line 477, in __rich_console__
    yield from self._render(console, render_options, widths)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/table.py", line 790, in _render
    lines = console.render_lines(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1294, in render_lines
    lines = list(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/segment.py", line 281, in split_and_crop_lines
    for segment in segments:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1259, in render
    for render_output in iter_render:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/padding.py", line 97, in __rich_console__
    lines = console.render_lines(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1294, in render_lines
    lines = list(
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/segment.py", line 281, in split_and_crop_lines
    for segment in segments:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/console.py", line 1259, in render
    for render_output in iter_render:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/syntax.py", line 554, in __rich_console__
    text = self.highlight(code, self.line_range)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/syntax.py", line 470, in highlight
    text.append_tokens(tokens_to_spans())
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/text.py", line 966, in append_tokens
    for content, style in tokens:
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/syntax.py", line 458, in tokens_to_spans
    _token_type, token = next(tokens)
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/rich/syntax.py", line 445, in line_tokenize
    for token_type, token in lexer.get_tokens(code):
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/pygments/lexer.py", line 187, in streamer
    for _, t, v in self.get_tokens_unprocessed(text):
  File "/Users/jwr003/coding/pytest-fold/venv/lib/python3.10/site-packages/pygments/lexer.py", line 629, in get_tokens_unprocessed
    m = rexmatch(text, pos)
KeyboardInterrupt

Source Code:

from textual import events
from textual.app import App
from textual.widgets.tabs import Tabs, Tab


class TabApp(App):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.keys_to_tabs = {
            "1": Tab("Summary", name="summary"),
            "2": Tab("Fail", name="fail"),
            "3": Tab("Pass", name="pass"),
            "4": Tab("Warning", name="warning"),
            "5": Tab("Error", name="error"),
            "6": Tab("Skip", name="skip"),
            "7": Tab("XFail", name="xfail"),
            "8": Tab("XPass", name="xpass"),
        }
        tabs = list(self.keys_to_tabs.values())
        self.tab_bar = Tabs(tabs)

    def on_load(self):
        self.bind("q", "quit", "Quit")

    async def on_key(self, event: events.Key) -> None:
        """Define events to call when keys are pressed"""
        tab = self.keys_to_tabs.get(event.key)

    async def on_mount(self):
        """Build layout here."""
        self.mount(self.tab_bar)


def main():
    TabApp().run()


if __name__ == "__main__":
    main()

[jeffwright13]

In fact, the same thing happens when you run textual/docs/examples/messages_and_events/color_changer.py (css branch):

from textual.app import App


class ColorChanger(App):
    def on_key(self, event):
        if event.key.isdigit():
            self.background = f"on color({event.key})"


ColorChanger.run(log="textual.log")

[USLTD]

@jeffwright13,
Reason is simple - CSS branch is in active development to add working and fully functional CSS processor and developers don't have any time to check for errors. When they will finish processor then they will check and fix those errors