dpkg error: pycompile: not found

Question

sudo apt-get remove --purge mysql-server mysql-client mysql-common

I am getting the following error as I try to remove mysql using the above command:

Answer 1

Ahhhh, yes. The venerable "Catch-22" situation of Debian package management. It boils down to Debian depending on py3compile as part of the libpython3.x package when that package provides the py3compile as well; it's a no-go, there.

I too was bitten by this unable to get py3compile working again for I had too deleted the entire /usr/[/local]/lib/python3* directories.

Once done, nothing in Debian package management tool can help you get back to a working Python3 environment. You must do meat-ball surgery.

Reconstruction of Python3 in Debian entails three critical things:

• Restoring py3compile script (for most of you, you already have this)
• Restoring libpython3.7
• Restoring python binary

One could do the RE-copying of /usr[/local]/lib directory from another working Debian host/system. But this time, I shall detail the steps from within the broken host in question (as if you do NOT have another working host).

Step 1 - Download Packages

Download the impacted Debian packages:

cd /tmp
apt-get download libpython3.7-minimal
apt-get download python3.7-minimal
apt-get download python3-minimal # (this is important)
apt-get download libpython3.7-stdlib
apt-get download python3.7

Step 2 - Cleanup

Clean up old stuff

rm -rf /usr[/local]/lib/python3.7*
rm -rf /usr[/local]/bin/python3.7*
update-alternatives --remove python3 /usr[/local]/bin/python3.7
hash -r  # removes cached python3 binary path

Step 3 - Extract files from packages

Let us extract the missing py3compile

cd /tmp
dpkg-deb -x python3-minimal_3.7.3-1_amd64.deb missing
dpkg-deb -x python3.7-minimal_3.7.3-2_amd64.deb missing
dpkg-deb -x libpython3.7-minimal_3.7.3-2_amd64.deb missing
dpkg-deb -x libpython3.7-stdlib_3.7.3-2_amd64.deb missing
dpkg-deb -x python3.7_3.7.3-2_amd64.deb missing

Step 3

Manually install over your root filesystem

cd /tmp/missing
ls -lR /tmp/missing  # if you are curious about overwriting your HD
sudo cp -rpfv /tmp/missing/*  /

Step 4 - Verification

Start up Python3

python3
Python 3.7.3 (default, Apr  3 2019, 05:39:12) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

Test import and show version

>>> import sys
>>> print(sys.version_info)
sys.version_info(major=3, minor=7, micro=3, releaselevel='final', serial=0)
>>>
>>> quit()

Step 5 - Clean up ourselves

rm -rf /tmp/missing

Step 6 - Officially reinstall Python via Debian APT

dpkg -s -a  | grep  reinstreq
# Any listing also needs to be reinstalled along with python3
apt-get install --reinstall python3

Most likely, you got MANY packages that are in that stuck state of "reinstreq" state.

apt-get autoclean
apt-get autoremove
# (MANY PACKAGES FAILED TO BE INSTALLED)

At this point, you will have to manually reinstall each and every one of those listed by apt-get autoremove...

apt-get install --fix-broken --reinstall 

Last Step - Reinstalling impacted half-state Debian packages

Let me guess, you got the following error:

E: Internal Error, No file name for XXXXXX

I will tell you that you probably had a newer Debian release in your /etc/apt/sources.list for awhile, it went all down south (bad), and took that newer release out of the sources.list file (in effort to revert back to a 'stable' release): that's not an unrecoverable thing to me here, just that you jerked the Debian package database around a bit there ... rather brusquely.

The resolution of the last step entails a restoration and stabilization of the Debian package management database by reinstalling nearly everything. I will detail it later but the link to follow is given here.