`AttributeError: __exit__` when creating subprocess in sample python code

[mylogon341]

Hi. I'm very new to python (currently a lead ios dev) and have little experience in debugging (beyond google). I am trying to run the rgb-to-gif.py script on a pi zero w (headless). Building, earlier on, i used the make I2C_MODE=RPI method. I believe it is using python2.7 by default. When I try to run it, I just end up hitting this error, which i'm having trouble finding help with elsewhere on the ole' internet.
I've literally changed nothing in the code, and it looks like I successfully built the rawrgb correctly. But if no one else is having this issue, I would suggest i've skimmed over an important detail somewhere 🤔

Traceback (most recent call last):
  File "rgb-to-gif.py", line 43, in <module>
    with subprocess.Popen(["sudo", RAW_RGB_PATH, "{}".format(fps)], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as camera:
AttributeError: __exit__

Thanks

[strangerman]

I'm having the same issue. Were you able to find a solution for this?

[Gadgetoid]

This is an obtuse error and no mistake. Python classes are supposed to define __enter__ and __exit__ methods which allow for with X as Y: to work. __enter__ is called at the start of the with, and __exit__ is called when it goes out of scope.

It's possible that in Python 2.x these attributes aren't defined on subprocess.Popen. In fact this very bug is described here: https://bugs.python.org/issue13202

Looks like context management support (the __enter__ and __exit__ methods) was not added to subprocess.Popen until Python 3.2.

Solution: make sure you're running with Python 3, which is the default language this should be built against, the the default interpreter when you run the file as ./rgb-to-gif.py without explicitly specifying python.

Since Python 2.x is now end of life I'll tag this as a notice to anyone running into the same issue.