[New-bugs-announce] [issue43716] curses.pair_number() function incorrect value under Windows

[Peter J. Farley III]

New submission from Peter J. Farley III <pjfarley3 at gmail.com>:

curses.pair_number() result under Windows (console or Terminal window) value must be shifted by 16 bits to be valid to use as input to the curses.pair_content() function.

If the pair number result is not shifted, the call to curses.pair_content() fails with an overflow error:

Traceback (most recent call last):
  File "C:\Users\MyUser\test\curses-color.py", line 126, in <module>
    curses.wrapper(main)
  File "C:\Python38\lib\curses\__init__.py", line 105, in wrapper
    return func(stdscr, *args, **kwds)
  File "C:\Users\MyUser\test\curses-color.py", line 72, in main
    fg, bg = curses.pair_content (pair)
OverflowError: signed short integer is greater than maximum

The attached curses program demonstrates the correct functioning using the pair value shift under Windows.  Comment out the "if" and shift lines to reproduce the overflow error.

Environment information:

Windows 10 (latest updates)
Windows cmd.exe window or Windows Terminal Version: 1.6.10571.0
Python 3.8.7
windows-curses 2.2.0

Also tested in:

Ubuntu 20.04 (WSL2)
ncurses6/focal,now 6.2-0ubuntu2 amd64

----------
components: Extension Modules
files: curses-color-1.py
messages: 390137
nosy: pjfarleyiii
priority: normal
severity: normal
status: open
title: curses.pair_number() function incorrect value under Windows
versions: Python 3.8
Added file: https://bugs.python.org/file49931/curses-color-1.py

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43716>
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