Ubuntu 20.10: references to old Ubuntu packages

[tobiasdiez]

Describe the bug
On Ubuntu 20.10 the Python installation is referencing some old Ubuntu packages that are missing. In more detail, if used with

container: 
      image: ubuntu:20.10

then one gets errors such as

     Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/__w/sagetrac-mirror/sagetrac-mirror/src/.venv/lib/python3.8/site-packages/setuptools/__init__.py", line 18, in <module>
        from setuptools.dist import Distribution
      File "/__w/sagetrac-mirror/sagetrac-mirror/src/.venv/lib/python3.8/site-packages/_virtualenv.py", line 89, in exec_module
        old(module)
      File "/__w/sagetrac-mirror/sagetrac-mirror/src/.venv/lib/python3.8/site-packages/setuptools/dist.py", line 32, in <module>
        from setuptools import windows_support
      File "/__w/sagetrac-mirror/sagetrac-mirror/src/.venv/lib/python3.8/site-packages/setuptools/windows_support.py", line 2, in <module>
        import ctypes
      File "/__t/Python/3.8.7/x64/lib/python3.8/ctypes/__init__.py", line 7, in <module>
        from _ctypes import Union, Structure, Array
    ImportError: libffi.so.6: cannot open shared object file: No such file or directory

or

import readline
ImportError: libreadline.so.7: cannot open shared object file: No such file or directory

These can be fixed by manually downloading the corresponding packages from the old Ubuntu distribution, e.g. bionic.

Which version of the action are you using?

• v1
• v2
• Some other tag (such as v2.0.1 or master)

Environment

• self-hosted
• Linux
• Windows
• Mac

If applicable, please specify if you're using a container: ubuntu:20.10

Python Versions
3.8 and 3.9, at least

To Reproduce
Steps to reproduce the behavior:

1. Use setup-python in a ubuntu:20.10 container
2. Import something from _ctypes or readline
3. Get error

Run/Repo Url
https://github.com/sagemath/sagetrac-mirror/runs/1870813916?check_suite_focus=true
and
https://github.com/sagemath/sagetrac-mirror/runs/1862181456?check_suite_focus=true

[avihaybar]

ImportError: libffi.so.6: cannot open shared object file: No such file or directory

This happens to me on Ubuntu 20.04 LTS too with Python 3.8.
I did notice that the cached Python version for 3.8 is 3.8.11 which probably disregard the platform version.
Pinning down the version to 3.8.12 is downloading the correct python-3.8.12-linux-20.04-x64.tar.gz .
Ubuntu 20.04 and later uses the updated libffi.so.7 while the cached Python version is looking for libffi.so.6.
see more info here

[dsame]

Hello @avihaybar,

The solution suggested by @illia-v is to be discussed and it can take a lot of time. Meanwhile, i suggest you to install the required library manually, will it work for you? Do you need our help to install those libraries within your pipeline?

[avihaybar]

thanks for the reply, @dsame.
We have since upgraded internally to Python 3.9.x where the issue is resolved.

[dsame]

Thanks @avihaybar for your note. i am going to close this. Feel free to open new issue or reopen this one in case of any problem

[dsame]

the same root cause leads to the SEGAULT #442