Log widget with a border tries to render a line -1

[gunslingerfry]

Have you checked closed issues? yes

Have you checked against the most recent version of Textual? yes

The bug

Please give a brief but clear explanation of the issue. If you can, include a complete working example that demonstrates the bug. Check it can run without modifications.

If you add a border to the log widget and click slightly above the border it attempts to run render_line with a y=-1 and crashes.

minimum example:

#!/usr/bin/env -S uv run --script --no-config
# /// script
# requires-python = ">=3.12"
# dependencies = [
#     "textual >=2.1.2",
#     "textual-dev"
# ]
# ///

from textual.app import App, ComposeResult
from textual.widgets import Log

class MyApp(App):
    def compose(self) -> ComposeResult:
        self.my_log = Log()
        self.my_log.styles.border = ("round", "white")
        yield self.my_log

if __name__ == "__main__":
    MyApp().run()

Then click above the border.

Stack Trace

╭──────────────────────────────────────────────────────────────────────────────────────────────────────────────── Traceback (most recent call last) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/app.py:3748 in on_event                                                                                                                                         │
│                                                                                                                                                                                                                                                                    │
│   3745 │   │   │   │   │   │   # Shouldn't occur, since at the very least this will find the Sc ╭──────────────────────────────────────── locals ────────────────────────────────────────╮                                                                         │
│   3746 │   │   │   │   │   │   self._mouse_down_widget = None                                   │     _ = Region(x=0, y=0, width=262, height=57)                                         │                                                                         │
│   3747 │   │   │   │                                                                            │ event = MouseDown(None, x=2, y=0, pointer_x=2.0, pointer_y=0.0, button=1)              │                                                                         │
│ ❱ 3748 │   │   │   │   self.screen._forward_event(event)                                        │  self = MyApp(title='MyApp', classes={'-dark-mode'}, pseudo_classes={'dark', 'focus'}) │                                                                         │
│   3749 │   │   │   │                                                                            ╰────────────────────────────────────────────────────────────────────────────────────────╯                                                                         │
│   3750 │   │   │   │   # If a MouseUp occurs at the same widget as a MouseDown, then we should                                                                                                                                                                     │
│   3751 │   │   │   │   # consider it a click, and produce a Click event.                                                                                                                                                                                           │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/screen.py:1533 in _forward_event                                                                                                                                │
│                                                                                                                                                                                                                                                                    │
│   1530 │   │   │   elif isinstance(event, events.MouseDown) and not self.app.mouse_captured:    ╭───────────────────────────────── locals ──────────────────────────────────╮                                                                                      │
│   1531 │   │   │   │   self._box_select = event.shift                                           │ event = MouseDown(None, x=2, y=0, pointer_x=2.0, pointer_y=0.0, button=1) │                                                                                      │
│   1532 │   │   │   │   self._mouse_down_offset = event.screen_offset                            │  self = Screen(id='_default')                                             │                                                                                      │
│ ❱ 1533 │   │   │   │   select_widget, select_offset = self.get_widget_and_offset_at(            ╰───────────────────────────────────────────────────────────────────────────╯                                                                                      │
│   1534 │   │   │   │   │   event.screen_x, event.screen_y                                                                                                                                                                                                          │
│   1535 │   │   │   │   )                                                                                                                                                                                                                                           │
│   1536 │   │   │   │   if (                                                                                                                                                                                                                                        │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/screen.py:634 in get_widget_and_offset_at                                                                                                                       │
│                                                                                                                                                                                                                                                                    │
│    631 │   │   Returns:                                                                         ╭─────────── locals ───────────╮                                                                                                                                   │
│    632 │   │   │   Tuple of Widget and Offset, both of which may be None.                       │ self = Screen(id='_default') │                                                                                                                                   │
│    633 │   │   """                                                                              │    x = 2                     │                                                                                                                                   │
│ ❱  634 │   │   return self._compositor.get_widget_and_offset_at(x, y)                           │    y = 0                     │                                                                                                                                   │
│    635 │                                                                                        ╰──────────────────────────────╯                                                                                                                                   │
│    636 │   def find_widget(self, widget: Widget) -> MapGeometry:                                                                                                                                                                                                   │
│    637 │   │   """Get the screen region of a Widget.                                                                                                                                                                                                               │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/_compositor.py:904 in get_widget_and_offset_at                                                                                                                  │
│                                                                                                                                                                                                                                                                    │
│    901 │   │   y -= region.y + gutter_right                                                     ╭────────────────────────────────────────────── locals ──────────────────────────────────────────────╮                                                             │
│    902 │   │                                                                                    │  gutter_left = 1                                                                                   │                                                             │
│    903 │   │   visible_screen_stack.set(widget.app._background_screens)                         │ gutter_right = 1                                                                                   │                                                             │
│ ❱  904 │   │   line = widget.render_line(y)                                                     │       region = Region(x=0, y=0, width=262, height=57)                                              │                                                             │
│    905 │   │                                                                                    │         self = <Compositor size=Size(width=262, height=57) widgets={Screen(id='_default'), Log()}> │                                                             │
│    906 │   │   end = 0                                                                          │       widget = Log()                                                                               │                                                             │
│    907 │   │   start = 0                                                                        │            x = 1                                                                                   │                                                             │
│                                                                                                 │            y = -1                                                                                  │                                                             │
│                                                                                                 ╰────────────────────────────────────────────────────────────────────────────────────────────────────╯                                                             │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/widgets/_log.py:286 in render_line                                                                                                                              │
│                                                                                                                                                                                                                                                                    │
│   283 │   │   │   A rendered line.                                                             ╭───── locals ─────╮                                                                                                                                                │
│   284 │   │   """                                                                              │ scroll_x = 0     │                                                                                                                                                │
│   285 │   │   scroll_x, scroll_y = self.scroll_offset                                          │ scroll_y = 0     │                                                                                                                                                │
│ ❱ 286 │   │   strip = self._render_line(scroll_y + y, scroll_x, self.size.width)               │     self = Log() │                                                                                                                                                │
│   287 │   │   return strip                                                                     │        y = -1    │                                                                                                                                                │
│   288 │                                                                                        ╰──────────────────╯                                                                                                                                                │
│   289 │   def _render_line(self, y: int, scroll_x: int, width: int) -> Strip:                                                                                                                                                                                      │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/widgets/_log.py:304 in _render_line                                                                                                                             │
│                                                                                                                                                                                                                                                                    │
│   301 │   │   if y >= len(self._lines):                                                                                                                                                                                                                            │
│   302 │   │   │   return Strip.blank(width, rich_style)                                                                                                                                                                                                            │
│   303 │   │                                                                                                                                                                                                                                                        │
│ ❱ 304 │   │   line = self._render_line_strip(y, rich_style)                                                                                                                                                                                                        │
│   305 │   │   assert line._cell_length is not None                                                                                                                                                                                                                 │
│   306 │   │   line = line.crop_extend(scroll_x, scroll_x + width, rich_style)                                                                                                                                                                                      │
│   307 │   │   line = line.apply_offsets(scroll_x, y)                                                                                                                                                                                                               │
│                                                                                                                                                                                                                                                                    │
│ ╭────────────────────────────────────────────────────────────────────────────────────────────────────── locals ───────────────────────────────────────────────────────────────────────────────────────────────────────╮                                            │
│ │ rich_style = Style(color=Color('#e2e2e2', ColorType.TRUECOLOR, triplet=ColorTriplet(red=226, green=226, blue=226)), bgcolor=Color('#272727', ColorType.TRUECOLOR, triplet=ColorTriplet(red=39, green=39, blue=39))) │                                            │
│ │   scroll_x = 0                                                                                                                                                                                                      │                                            │
│ │       self = Log()                                                                                                                                                                                                  │                                            │
│ │      width = 260                                                                                                                                                                                                    │                                            │
│ │          y = -1                                                                                                                                                                                                     │                                            │
│ ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯                                            │
│                                                                                                                                                                                                                                                                    │
│ /home/matthew/.cache/uv/environments-v2/test-95a82182e4a7c559/lib/python3.12/site-packages/textual/widgets/_log.py:324 in _render_line_strip                                                                                                                       │
│                                                                                                                                                                                                                                                                    │
│   321 │   │   if y in self._render_line_cache and selection is None:                                                                                                                                                                                               │
│   322 │   │   │   return self._render_line_cache[y]                                                                                                                                                                                                                │
│   323 │   │                                                                                                                                                                                                                                                        │
│ ❱ 324 │   │   _line = self._process_line(self._lines[y])                                                                                                                                                                                                           │
│   325 │   │                                                                                                                                                                                                                                                        │
│   326 │   │   line_text = Text(_line, no_wrap=True)                                                                                                                                                                                                                │
│   327 │   │   line_text.stylize(rich_style)                                                                                                                                                                                                                        │
│                                                                                                                                                                                                                                                                    │
│ ╭────────────────────────────────────────────────────────────────────────────────────────────────────── locals ───────────────────────────────────────────────────────────────────────────────────────────────────────╮                                            │
│ │ rich_style = Style(color=Color('#e2e2e2', ColorType.TRUECOLOR, triplet=ColorTriplet(red=226, green=226, blue=226)), bgcolor=Color('#272727', ColorType.TRUECOLOR, triplet=ColorTriplet(red=39, green=39, blue=39))) │                                            │
│ │  selection = None                                                                                                                                                                                                   │                                            │
│ │       self = Log()                                                                                                                                                                                                  │                                            │
│ │          y = -1                                                                                                                                                                                                     │                                            │
│ ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯                                            │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
IndexError: list index out of range

textual diagnose

Textual Diagnostics

Versions

Name	Value
Textual	2.1.2
Rich	13.9.4

Python

Name	Value
Version	3.12.4
Implementation	CPython
Compiler	GCC 14.1.1 20240522
Executable	/home/matthew/test/textual-log-bug/.venv/bin/python3

Operating System

Name	Value
System	Linux
Release	6.12.10-arch1-1
Version	#1 SMP PREEMPT_DYNAMIC Sat, 18 Jan 2025 02:26:57 +0000

Terminal

Name	Value
Terminal Application	Unknown (konsole)
TERM	xterm-256color
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=262, height=57
legacy_windows	False
min_width	1
max_width	262
is_terminal	True
encoding	utf-8
max_height	57
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[github-actions]

We found the following entries in the FAQ which you may find helpful:

• Does Textual support images?
• How do I center a widget in a screen?
• How do I pass arguments to an app?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[github-actions]

Don't forget to star the repository!

Follow @textualizeio for Textual updates.

[gunslingerfry]

You rock @willmcgugan !