I also performed an upgrade of an Ubuntu Desktop system from xenial w/ -proposed enabled to artful so that python3-minimal from artful-proposed would be used and the upgrade proceeded without error.
bdmurray@clean-xenial-amd64:/tmp/ubuntu-release-upgrader-355quvv3$ grep -C10 python3-minimal /var/log/dist-upgrade/apt-term.log
Processing triggers for mime-support (3.59ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) ...
Processing triggers for cups (2.1.3-4) ...
Updating PPD files for postscript-hp ...
Setting up libssl1.0.0:amd64 (1.0.2g-1ubuntu13.6) ...
Setting up libpython3.6-minimal:amd64 (3.6.3-1ubuntu1) ...
Setting up libexpat1:amd64 (2.2.3-1) ...
Setting up python3.6-minimal (3.6.3-1ubuntu1) ...
Processing triggers for libc-bin (2.26-0ubuntu2.1) ...
(Reading database ... 209379 files and directories currently installed.)
Preparing to unpack .../python3-minimal_3.6.3-0ubuntu3_amd64.deb ...
Unpacking python3-minimal (3.6.3-0ubuntu3) over (3.5.1-3) ...
Setting up python3-minimal (3.6.3-0ubuntu3) ...
(Reading database ... 209379 files and directories currently installed.)
Preparing to unpack .../python3_3.6.3-0ubuntu3_amd64.deb ...
running python pre-rtupdate hooks for python3.6...
Unpacking python3 (3.6.3-0ubuntu3) over (3.5.1-3) ...
Preparing to unpack .../mime-support_3.60ubuntu1_all.deb ...
Unpacking mime-support (3.60ubuntu1) over (3.59ubuntu1) ...
Selecting previously unselected package libpython3.6-stdlib:amd64.
Preparing to unpack .../libpython3.6-stdlib_3.6.3-1ubuntu1_amd64.deb ...
Unpacking libpython3.6-stdlib:amd64 (3.6.3-1ubuntu1) ...
Selecting previously unselected package python3.6.
I also performed an upgrade of an Ubuntu Desktop system from xenial w/ -proposed enabled to artful so that python3-minimal from artful-proposed would be used and the upgrade proceeded without error.
bdmurray@ clean-xenial- amd64:/ tmp/ubuntu- release- upgrader- 355quvv3$ grep -C10 python3-minimal /var/log/ dist-upgrade/ apt-term. log 1ubuntu13. 6) ... 6-minimal: amd64 (3.6.3-1ubuntu1) ... minimal_ 3.6.3-0ubuntu3_ amd64.deb ... 3.6.3-0ubuntu3_ amd64.deb ... support_ 3.60ubuntu1_ all.deb ... 6-stdlib: amd64. 6-stdlib_ 3.6.3-1ubuntu1_ amd64.deb ... 6-stdlib: amd64 (3.6.3-1ubuntu1) ...
Processing triggers for mime-support (3.59ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) ...
Processing triggers for cups (2.1.3-4) ...
Updating PPD files for postscript-hp ...
Setting up libssl1.0.0:amd64 (1.0.2g-
Setting up libpython3.
Setting up libexpat1:amd64 (2.2.3-1) ...
Setting up python3.6-minimal (3.6.3-1ubuntu1) ...
Processing triggers for libc-bin (2.26-0ubuntu2.1) ...
(Reading database ... 209379 files and directories currently installed.)
Preparing to unpack .../python3-
Unpacking python3-minimal (3.6.3-0ubuntu3) over (3.5.1-3) ...
Setting up python3-minimal (3.6.3-0ubuntu3) ...
(Reading database ... 209379 files and directories currently installed.)
Preparing to unpack .../python3_
running python pre-rtupdate hooks for python3.6...
Unpacking python3 (3.6.3-0ubuntu3) over (3.5.1-3) ...
Preparing to unpack .../mime-
Unpacking mime-support (3.60ubuntu1) over (3.59ubuntu1) ...
Selecting previously unselected package libpython3.
Preparing to unpack .../libpython3.
Unpacking libpython3.
Selecting previously unselected package python3.6.