termios.tcgetattr changes settings rather than just returning them

[sebbASF]

cpython/Lib/getpass.py

Line 68 in bc3705a

old = termios.tcgetattr(fd) # a copy to save

This is using Python 3.13.1+ on a-shell Mini (iPad Mini)

Whilst trying to investigate why getpass.getpass() does not recognise the Enter or ^d key as input terminator, I discovered that this appears to be caused by termios.tcgetattr(fd)

For a simple demo, try the following:

import sys
import termios
print(repr(sys.stdin.readline())) # this behaves as expected; Enter terminates input, as do ^D (EOF) and ^J
fd = sys.stdin.fileno()
old = termios.tcgetattr(fd)
print(repr(sys.stdin.readline())) # this does not behave as expected; only ^J terminates input; Enter is converted into CR

This means that using getpass.getpass() does not return sys.stdin to its original state.

[sebbASF]

I tried re-installing a-Shell mini - no change.
Also tried installing a-Shell - same behaviour.
In case it helps, the output from tcgetattr is:

[0, 0, 1, 392, 230400, 230400, [b'\x04', b'\x00', b'\x00', b'\x7f', b'\x00', b'\x00', b'\x00', b'\x00', b'\x03', b'\x00', b'\x1a', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00']]

[sebbASF]

Forgot to add: the output is the same if tcgetattr is called again