Description of problem:
A conflict with file from package python3-libs file appears when try to upgrade from Fedora 23 to Rowhide.
The following error appears:
Total 948 kB/s | 56 MB 01:00
Running transaction check
Transaction check succeeded.
Running transaction test
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: Transaction check error:
file /usr/lib64/libpython3.so from install of system-python-libs-3.5.1-7.fc25.x86_64 conflicts with file from package python3-libs-3.4.3-6.fc23.x86_64
Version-Release number of selected component (if applicable):
Steps to Reproduce:
What is the exact way of upgrading?
M(In reply to Miro Hrončok from comment #1)
> What is the exact way of upgrading?
from a Fedora 23 system (default install):
1) dnf -y update
2) dnf -y install fedora-repos-rawhide
3) enable the rawhide repos
4) dnf -y update
With the same steps we also see bug #1339731
I believe we forgot to add some Conflicts:
Tested it on Friday and I was able to reproduce the problem, however today when I retested on a clean f23 machine and upgraded to rawhide, it worked as expected with no conflicts.
Dnf got updated so maybe somehow it got resolved? Couldn't find something specific in the release notes however.
Could you retest it and tell me if you are still getting this error?
Ok I isolated some test cases.
A fedora 23 image was used for all systems, updated with dnf as of May 30.
1) # dnf install fedora-repos-rawhide
# dnf update --enablerepo-rawhide --refresh
Updates complete successfully, machine doesn't reboot however due to probably unrelated issue (rawhide kernel?)
Also the same with:
# dnf update --releasever=rawhide --nogpgcheck --refresh # nogpgcheck for unsigned kernel
2) # dnf distro-sync --releasever=24 --refresh
3) # dnf install dnf-plugin-system-upgrade
# dnf system-upgrade download --refresh --releasever=24
As documented here  and it works also.
4) # dnf update --releasever=24 --refresh
This is where the error appears and also the bug #1339731
The explicit conflict should solve even potential problems and cannot do any harm (expect when done wrong).
I've tested today with the steps from comment #2. Did not see any conflicts, the resulting system has: