To distro-sync or not distro-sync?

[Miroslav Suchý]

I am trying to upgrade to F23 (I know still not finished but...)

In past I always done 'distro-sync'. Albeit with yum.

Now I tried:
  dnf system-upgrade download --releasever=23 --distro-sync
  dnf system-upgrade download --releasever=23 --distro-sync --best
  dnf system-upgrade download --releasever=23 --distro-sync --best --allowerasing

And all of them fail. See below for full log.

On the other hand:
  dnf system-upgrade download --releasever=23
succeed.

Actually most of the problem are caused by retired or obsoleted packages. E.g fedup-dracut or rubygem-celluloid (this
one reported as BZ 1275030).

My question is should we use --distro-sync at all? Are users supposed to remove obsoleted packages manually?

If I do not pass --distro-sync then some packages are not upgraded. E.g in my case after upgrade I have
grub2-tools-2.02-0.16.fc22.x86_64.


Full log of failures.

# dnf system-upgrade download --releasever=23 --distro-sync --best
cannot install both kernel-devel-4.2.3-300.fc23.x86_64 and kernel-devel-3.19.4-200.fc21.x86_64.
package rubygem-celluloid-0.15.2-2.fc22.noarch requires rubygem(timers) < 1.2, but none of the providers can be installed.
package rubygem-celluloid-0.15.2-2.fc22.noarch requires rubygem(timers) < 1.2, but none of the providers can be installed.
package fedup-dracut-0.9.2-1.fc22.x86_64 requires librpm.so.3()(64bit), but none of the providers can be installed.
package rpm-libs-4.12.0.1-12.fc22.x86_64 requires rpm = 4.12.0.1-12.fc22, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

# dnf system-upgrade download --releasever=23 --distro-sync
Error: package rubygem-celluloid-0.15.2-2.fc22.noarch requires rubygem(timers) < 1.2, but none of the providers can be
installed.
package grub2-tools-1:2.02-0.23.fc23.x86_64 requires librpm.so.7()(64bit), but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

# dnf system-upgrade download --releasever=23 --distro-sync --best --allowerasing
Error: package rubygem-celluloid-0.15.2-2.fc22.noarch requires rubygem(timers) < 1.2, but none of the providers can be
installed.
package fedup-dracut-0.9.2-1.fc22.x86_64 requires librpm.so.3()(64bit), but none of the providers can be installed

-- 
Miroslav Suchy, RHCA
Red Hat, Senior Software Engineer, #brno, #devexp, #fedora-buildsys