buffer overflow error with Python 3.14

[daeho-ro]

Hello, recently I got the error with Python 3.14,

  Traceback (most recent call last):
    File "/opt/homebrew/Cellar/cfv/3.1.0/bin/cfv", line 3, in <module>
      from cfv.common import main
    File "/opt/homebrew/Cellar/cfv/3.1.0/libexec/lib/python3.14/site-packages/cfv/common.py", line 49, in <module>
      from cfv import ui
    File "/opt/homebrew/Cellar/cfv/3.1.0/libexec/lib/python3.14/site-packages/cfv/ui.py", line 10, in <module>
      from cfv import term
    File "/opt/homebrew/Cellar/cfv/3.1.0/libexec/lib/python3.14/site-packages/cfv/term.py", line 28, in <module>
      scrwidth = getscrwidth()
    File "/opt/homebrew/Cellar/cfv/3.1.0/libexec/lib/python3.14/site-packages/cfv/term.py", line 16, in getscrwidth
      h, w = struct.unpack('h h', ioctl(tty.fileno(), TIOCGWINSZ, '\0' * struct.calcsize('h h')))
                                  ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  SystemError: buffer overflow

and so wonder this can be fixed to work with newer Python.

Can you take a look?
Thanks,

[lxp]

Are you sure this only happens with Python 3.14?
Our testsuite runs with Python 3.14 (https://github.com/cfv-project/cfv/actions/runs/18606013641/job/53055541052).
My guess is that it is some specific compatibility issue with the terminal you are using.
Can you provide instructions on how you run cfv and which OS and terminal you are using?
Since you are using Homebrew, you might be running on MacOS, which is currently not fully supported yet, see: #30

[daeho-ro]

Never expect that, but reasonable.

As your expectation, I use homebrew on MacOS 15 and the terminal is Warp (zsh).
We are trying to migrate all the python packages uses Python 3.14, and cfv too.

• cfv: migrate to python@3.14 Homebrew/homebrew-core#248673

We did some manual fix in this PR, but not sure that's enough.

[lxp]

Thanks for providing additional infos and even including a fix!
It seems that exactly the affected code line is not called in our CI tests since it does not run on a TTY.
You are right that the exception is caused by a change in Python 3.14: python/cpython#132915
It seems that the TIOCGWINSZ ioctl expects a struct of 4 shorts (see https://man7.org/linux/man-pages/man2/TIOCSWINSZ.2const.html) while our code only supplies a buffer of two shorts.
Your fix seems valid. I will try to reproduce it, apply this fix and release a new version in the next days.

[lxp]

Version 3.2.0 is now released.