Upgrading fails if ffmpeg-libs (rpmfusion-free-updates) is installed. I know this is not part of fedora, so not giving negative feedback, but a lot of user will have installed it.

$ LC_ALL=C sudo dnf upgrade --enablerepo=updates-testing --advisory=FEDORA-2020-5d50681597
Dependencies resolved.

 Problem: problem with installed package ffmpeg-libs-4.2.3-4.fc32.x86_64
  - package ffmpeg-libs-4.2.3-4.fc32.x86_64 requires libdav1d.so.3()(64bit), but none of the providers can be installed
  - cannot install both libdav1d-0.7.1-1.fc32.x86_64 and libdav1d-0.5.2-2.fc32.x86_64
  - cannot install both libdav1d-0.5.2-2.fc32.x86_64 and libdav1d-0.7.1-1.fc32.x86_64
  - cannot install the best update candidate for package libdav1d-0.5.2-2.fc32.x86_64
================================================================================================================================================================
 Package                             Architecture                      Version                                 Repository                                  Size
================================================================================================================================================================
Skipping packages with conflicts:
(add '--best --allowerasing' to command line to force their upgrade):
 libdav1d                            x86_64                            0.7.1-1.fc32                            updates-testing                            376 k

Transaction Summary
================================================================================================================================================================
Skip  1 Package

Nothing to do.
Complete!

Same here. This is now a catch-22: rpmfusion cannot rebuild until this update goes stable from what I know.

This includes an ABI change: should this be hitting F32 at all? I expect other packages in Fedora will also need a rebuild? (I can't seem to find an update announcement for the ABI bump on -devel)

WFM

FYI I'm pushing the rebuilt ffmpeg package to stable repo tomorrow

Hey sorry for noticing that only now. Since dav1d was already at 0.7.0 in dist-git, I thought they was no SONAME bump.

There is a need to be careful when merging branches. dav1d was in 0.7.0 only on the master branch on purpose.

ABI break in stable fedora release has severe implications: - In-habitability to downgrade dependencies to the release repository as a fallback for any regression. - Break many other 3rd part repos like any copr. Advertising them is way too heavy leading to uncertainty an stability issues to end-users face. - There is a need to advertise many people to handle the break, each of them have their own pace. - When projects are still breaking ABI, then it's not certain that a new ABI break won't be soon, so unless it's proven that upstream have found their stable ABI or even care at not breaking ABI, there will be many breakage. - etc

I don't like this at all. But above all, I want to avoid an in-between situation, so here is my +1

If one wants to fetch the latest dav1d code, it's possible to rely on the rpmfusion/ffmpeg container from docker hub instead.