Have you checked closed issues? Yes
Have you checked against the most recent version of Textual? Yes
The bug
Selection.extract() crashes with IndexError: list index out of range when selecting text in a single-line widget positioned below row 0 on screen.
Widget.get_selection() passes the selection's coordinates directly to Selection.extract() without translating them to widget-local text coordinates. extract() bounds-checks end_line but not start_line, causing the crash when start_line exceeds the text line count.
To reproduce the bug:
from textual.selection import Selection
from textual.geometry import Offset
sel = Selection(start=Offset(x=140, y=13), end=None)
sel.extract("▶ Loaded: 40 skills") # IndexError thrown: list index out of range
Textual Diagnostics
Versions
| Name |
Value |
| Textual |
8.1.1 |
| Rich |
14.3.3 |
Python
| Name |
Value |
| Version |
3.10.9 |
| Implementation |
CPython |
| Compiler |
Clang 13.0.0 (clang-1300.0.29.30) |
| Executable |
/Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10 |
Operating System
| Name |
Value |
| System |
Darwin |
| Release |
22.6.0 |
| Version |
Darwin Kernel Version 22.6.0: Tue Jul 15 08:22:28 PDT 2025; root:xnu-8796.141.3.713.2~2/RELEASE_X86_64 |
Terminal
| Name |
Value |
| Terminal Application |
vscode (1.110.0) |
| TERM |
xterm-256color |
| COLORTERM |
truecolor |
| FORCE_COLOR |
Not set |
| NO_COLOR |
Not set |
Rich Console options
| Name |
Value |
| size |
width=108, height=14 |
| legacy_windows |
False |
| min_width |
1 |
| max_width |
108 |
| is_terminal |
True |
| encoding |
utf-8 |
| max_height |
14 |
| justify |
None |
| overflow |
None |
| no_wrap |
False |
| highlight |
None |
| markup |
None |
| height |
None |
Discovered via this issuue: OpenHands CLI #13408
