io.UnsupportedOperation: fileno

[eeriemyxi]

I am getting this error on a fairly simple script.

import sixel
import io

def main():
    with open("box.png", "rb") as img:
        f = io.StringIO()
        # f = io.BytesIO()
        writer = sixel.SixelWriter()
        writer.draw(img, output=f)

if __name__ == "__main__":
    main()

Traceback (most recent call last):
  File "/home/myxi/Documents/coding/python/dumps/test.py", line 12, in <module>
    main()
  File "/home/myxi/Documents/coding/python/dumps/test.py", line 9, in main
    writer.draw(img, output=f)
  File "/home/myxi/.asdf/installs/python/3.11.8/lib/python3.11/site-packages/sixel/sixel.py", line 69, in draw
    self.save_position(output)
  File "/home/myxi/.asdf/installs/python/3.11.8/lib/python3.11/site-packages/sixel/sixel.py", line 24, in save_position
    if os.isatty(output.fileno()):
                 ^^^^^^^^^^^^^^^
io.UnsupportedOperation: fileno

I have tried both StringIO and BytesIO, but the error persists. The script worked fine on my machine when I wrote to sys.stdout for some reason. I did some googling and found out that this can be caused if you run the script in a limited environment of Python as offered by certain IDEs, but I am not running it in such an environment. I run it directly. This is how I run the command:

python test.py

The funny part is that this worked just fine:

import sixel
import io

def main():
    with open("box.png", "rb") as img:
        f = io.StringIO()
        conv = sixel.converter.SixelConverter(img)
        conv.write(f)

if __name__ == "__main__":
    main()

No errors. But I need the writer because I need to specify the position of the image.

I have tried the first script on Python 3.11.8 and Python 3.12.2. I get this error on both.

myxi :: coding/python/dumps » pip freeze
pillow==10.2.0
sixel==0.2.0

myxi :: coding/python/dumps » uname -a
Linux myxi 6.5.0-25-generic #25~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Feb 20 16:09:15 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

Python versions were compiled with gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0