pyenv building python on Linux Mint with WARNING: renaming "_ctypes"

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For some reason, pyenv is failing to install any versions of python due to an issue with libffi. I have all the libraries installed, yet I get:

*** WARNING: renaming "_ctypes" since importing it failed: libffi.so.8: cannot open shared object file: No such file or directory

The curious thing is libffi is installed, but it's a different version:

❯ find /usr -name '*ffi.so*'
/usr/lib/x86_64-linux-gnu/libffi.so
/usr/lib/x86_64-linux-gnu/libffi.so.7
/usr/lib/x86_64-linux-gnu/libffi.so.7.1.0

So, the build is trying libffi.so.8 even though libffi.so.7 is installed.

Can anybody explain how debian-based systems choose the version of the shared library? I've checked the .h and .pc files, but nothing jumps out at me showing why it would be referencing version 8.

❯ ldconfig -p | grep libffi.so
    libffi.so.7 (libc6,x86-64) => /lib/x86_64-linux-gnu/libffi.so.7
    libffi.so.7 (libc6) => /lib/i386-linux-gnu/libffi.so.7
    libffi.so (libc6,x86-64) => /lib/x86_64-linux-gnu/libffi.so

Additional note: I notice libffi is also installed by homebrew. However, it's the same version as Mint has installed, so it's not a conflict (as far as I can tell).

Any suggestions?

❯ uname -a
Linux mcrowe-XPS-15-9560 5.4.0-90-generic #101-Ubuntu SMP Fri Oct 15 20:00:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

❯ cat /etc/lsb-release 
DISTRIB_ID=LinuxMint
DISTRIB_RELEASE=20.2
DISTRIB_CODENAME=uma
DISTRIB_DESCRIPTION="Linux Mint 20.2 Uma"
pyenv python
1 Answers

FWIW, I am seeing a similar issue. When I installed 3.9.7 with pyenv, it found libffi correctly. Today, when I install 3.9.9 I get the same error as you.

*** WARNING: renaming "_ctypes" since importing it failed: libffi.so.8: cannot open shared object file: No such file or directory

The symptom that got me looking into this was an attempt to pip install blinker which gave me an error about missing _ctypes, which was odd since 3.9.7 had no issues.

ModuleNotFoundError: No module named '_ctypes'

In my case brew had updated to libffi 3.4 vs the 3.3 that Ubuntu 20.04 is using. I figure there must be some misordering of paths where it finds the brew headers to compile, but cannot find the brew .so to link.

I would like to learn to sort that out, but in the meantime, I did the following, answering y to the pyenv prompt to reinstall over existing 3.9.9

$ brew remove --ignore-dependencies libffi
$ pyenv install 3.9.9
$ brew install libffi

That was enough of a workaround to let me return to what I wanted to deal with.

user_19138160
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