Koji changed behaviour when downloading tasks, see the examples below:

$ rpm -q koji
koji-1.28.1-1.fc34.noarch
$ koji download-task --arch noarch --arch x86_64 --arch src 90835853
Downloading [1/15]: python-unversioned-command-3.11.0~rc1-2.fc38.noarch.rpm
[====================================] 100%  10.12 KiB
Downloading [2/15]: python3.11-debugsource-3.11.0~rc1-2.fc38.x86_64.rpm
[====================================] 100%   3.15 MiB
Downloading [3/15]: python3-idle-3.11.0~rc1-2.fc38.x86_64.rpm
...

And with the new version

$ rpm -q koji
koji-1.29.1-4.fc36.noarch
$ koji download-task --arch noarch --arch x86_64 --arch src 90835853
Download files names conflict, use --dirpertask

Version-Release number of selected component (if applicable):
koji-1.29.1-4.fc36.noarch

How reproducible:
100%

Steps to Reproduce:
See description

Actual results:
Koji works differently when downloading tasks.

Expected results:

Original behaviour is kept, same files can be replaced. Koji can report that same files will be overwritten and give the user an option how to avoid overwriting of files via --dirpertask.

Additional info:

This bug breaks Fedora CI and is another breaking change introduced via https://pagure.io/koji/c/6713d1651d73b1b9d5dec37d0c5e0d85fa41a3c5. We should roll back that breaking change and introduce it more carefully. We should start gating koji on Fedora CI validation.