Questions[gobject](ubuntu)

After updating from Ubuntu 20.04 to Ubuntu 20.10 I am not able to run PyGObject applications on a Python Virtual Environment.

I can reproduce the issue following these simple steps:

sudo apt-get install python3-venv
python3 -m venv venv
source env/bin/activate
pip install PyGObject==3.38.0
python3 hw.py

Where hw.py is the standard PyGObject Hello World:

#!/usr/bin/env python3

import gi
gi.require_version("Gtk", "3.0")
from gi.repository import Gtk

window = Gtk.Window(title="Hello World")
window.show()
window.connect("destroy", Gtk.main_quit)
Gtk.main()

When I try to run it, it throws this error:

$ python3 hw.py 
Traceback (most recent call last):
  File "hw.py", line 3, in <module>
    import gi
  File "/home/leinardi/temp/hw/venv/lib/python3.8/site-packages/gi/__init__.py", line 40, in <module>
    from . import _gi
ImportError: libffi.so.7: cannot open shared object file: No such file or directory

Running hw.py on the System Environment works correctly (the issue only happens when using the Virtual Environment).

A workaround is to find and provide a copy of libffi.so.7 in /usr/lib/x86_64-linux-gnu/ but, since this library version is not available inside the official repositories of Ubuntu 20.10, this is a difficult and unsafe operation.

I have two Ubuntu 18.04.1 LTS systems:

1. clean installation of Ubuntu 18.04.1 LTS
2. upgraded from Ubuntu 16.04.5 LTS

Note: All things in the both systems have been installed using APT (from deb-packages). I did not use pip/pip3, make install, checkinstall and other similar utilities. So it is absolutely on topic. It is Ubuntu, Ubuntu uses APT.

First system have the following pyc-files:

• /usr/lib/python2.7/dist-packages/gi/overrides/Dee.pyc
• /usr/lib/python3/dist-packages/gi/overrides/__pycache__/Dee.cpython-36.pyc
• /usr/lib/python2.7/dist-packages/gi/overrides/Unity.pyc
• /usr/lib/python3/dist-packages/gi/overrides/__pycache__/Unity.cpython-36.pyc

Second system do not have these files.

I can not find packages for these files with dpkg -S. But I can find for scripts (*.py).

As far I can understand these files came from gir1.2-dee-1.0 and gir1.2-unity-5.0.
But after re-installation of these packages the *.pyc files are not created.

What is wrong?
How to get *.pyc in their places? Will my system work normally without these files?

I am trying to package a program I wrote (using Pyqt4) into a single executable for linux. I tried using Pyinstaller however it has problems with importing Gio (for settings)

from gi.repository import Gio

Running the application would give:

ImportError: cannot import name Gio

I then tried to use bbFreeze. The problem here is that after compiling and running the application, I get this error message:

TypeError: GObject.__init__() takes exactly 0 arguments (1 given)

For bbFreeze this is my script I am running to compile the code:

#!/usr/bin/env python

from bbfreeze import Freezer

includes = ["gio"]
excludes = []

bbFreeze_Class = Freezer('dist', includes=includes, excludes=excludes)

bbFreeze_Class.addScript("main.py", gui_only=True)

bbFreeze_Class.use_compression = 0
bbFreeze_Class.include_py = True
bbFreeze_Class()

I am using Ubuntu 11.10 and Python 2.7. If someone can help that would be great. This is my first time writing Python and trying to compile it (so I am not sure if there are better alternatives).

What does introspection mean exactly? How is it useful for a programmer? Can somebody please explain in layman terms?