pyrepl fails with an ugly traceback when ioctls are not allowed on tty stdio

[glyph]

Bug report

Bug description:

If you remove the ability to write ioctls to tty stdio, for example on macOS by doing

sandbox-exec -p '(version 1) (import "system.sb") (allow process-exec) (allow file-read* (subpath "/"))' python3.13

Then PyREPL fails:

Python 3.13.3 (v3.13.3:6280bb54784, Apr  8 2025, 10:47:54) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/reader.py", line 584, in prepare
    self.console.prepare()
    ~~~~~~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/unix_console.py", line 342, in prepare
    tcsetattr(self.input_fd, termios.TCSADRAIN, raw)
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/fancy_termios.py", line 57, in tcsetattr
    termios.tcsetattr(fd, when, attrs.as_list())
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
termios.error: (1, 'Operation not permitted')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/__main__.py", line 6, in <module>
    __pyrepl_interactive_console()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/main.py", line 59, in interactive_console
    run_multiline_interactive_console(console)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/simple_interact.py", line 142, in run_multiline_interactive_console
    statement = multiline_input(more_lines, ps1, ps2)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/readline.py", line 389, in multiline_input
    return reader.readline()
           ~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/reader.py", line 744, in readline
    self.prepare()
    ~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/historical_reader.py", line 306, in prepare
    super().prepare()
    ~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/reader.py", line 593, in prepare
    self.restore()
    ~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/reader.py", line 607, in restore
    self.console.restore()
    ~~~~~~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/unix_console.py", line 372, in restore
    self.__maybe_write_code(self._rmkx)
    ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/unix_console.py", line 713, in __maybe_write_code
    self.__write_code(fmt, *args)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_pyrepl/unix_console.py", line 709, in __write_code
    self.__buffer.append((curses.tparm(fmt, *args), 1))
    ^^^^^^^^^^^^^
AttributeError: 'UnixConsole' object has no attribute '_UnixConsole__buffer'. Did you mean: '_UnixConsole__move'?

You can work around this, by re-enabling ioctls:

sandbox-exec -p '(version 1) (import "system.sb") (allow process-exec) (allow file-read* (subpath "/")) (allow file-ioctl (regex "^/dev/ttys[0-9]*"))' python3.13

but pyrepl should probably be robust to this and fall back to a regular console.

As requested, notifying @ambv

CPython versions tested on:

3.13

Operating systems tested on:

macOS

[feoh]

I wrote a naive patch adding an except clause for termios.error in reader.py and unix_consolele.py, but I can't figure out what the right way to handle the tcsetattr in fancy_termios.py because there's no restore() to call from there.

feoh@2da12f9

[sergey-miryanov]

If you don't mind, I would suggest you firstly fix the second exception and move __buffer declaration to the top of prepare function or even to __init__.