New subject: ExcludingolderbuildsofpackagesfromFedorawhentestingnewonesinCopr

8 Jul 2021


      Hello Copr users and developers.
When we update packages in Fedora, we regularly use Copr to test the impact of 
the upgrade.
For me, the procedure usually goes like this:
1) create a new copr with Fedora rawhide x86_64 chroot (and added Koji repo)
$ copr create $COPR 
--repo='http://kojipkgs.fedoraproject.org/repos/rawhide/latest/$basearch/' 
--chroot fedora-rawhide-x86_64 --delete-after-days 30
2) define and build the updated package in the copr
$ copr add-package-distgit $COPR --name $PKG --webhook-rebuild on --commit 
$BRANCH --namespace forks/$(whoami)
     $ copr build-package $COPR --name $PKG
3) get the list of dependent packages
$ repoquery -q --repo=rawhide{,-source} [--whatrequires $spkg for each 
subpackage] --recursive | grep src$ | pkgname
4) define and build the depended packages in the copr
$ parallel copr add-package-distgit $COPR --webhook-rebuild on --commit 
rawhide --name -- $(repoquery from above ...)
     $ parallel copr build-package $COPR --nowait --background --name -- 
$(repoquery from above ...)
5) analyze build failures, do a "control" rebuild in another copr if needed
However, this procedure has a flaw. Let's say I'm working on upgrading 
python-click from 7.x to 8.x. And let's say a package (even transitively) 
BuildRequires:
python3dist(click) < 8
The way that dnf dependency resolution works, that package will be built with 
Rawhide's python3-click 7.x and it will be marked as successful. However, I'd 
like to see a failure here to be notified that such package cannot be build and 
will be negatively impacted by the update.
Is there a way to solve this?  I have couple ideas, but none of them is fully 
working:
A) Compose my own repo with the updated package and Rawhide content without it, 
use that repo in the copr.
Pros:
- this is similar to what will happen in Koji once the package is updated
Cons:
- this requires tooling that I don't think exists
  - this requires a place to put that repo to
  - the repo creation could take a lot of time and would need to be repeated 
on-demand each time rawhide changes
  - Copr's Fedora chroots always include Fedora repos (maybe I can use 
custom-1-x86_64 chroot?)
B) Create a Fedora side tag, explicitly block the package from it, use that 
side tag's Koji repo.
Pros:
- same as (A)
Cons:
- I don't think on-demand side tags allow users to block packages
  - Copr's Fedora chroots always include Fedora repos (same as (A))
  - this wastes Koji's resources a bit
  - requires waiting for the initial Koji regen-repo
C) Block (exclude) python3-click < 8 from the chroot.
Pros:
- no custom repos required
  - no resources overhead
  - no time overhead
Cons:
- There is no way exclude packages in chroot settings. Mock settings possibly 
allow me to do this in config_opts['dnf.conf'].
  - The exclude could obfuscate root.log resolution problems logs.
  - Packager needs to figure out what exactly to exclude (possibly need to 
exclude all subpackage's NEVRAs from rawhide compose (and Koji buildroot if 
they differ))
Is there another way? If not, I think (C) is easiest to actually implement, if 
the chroot settings page in copr gains an "excludes" option.
-- 
Miro Hrončok
-- 
Phone: +420777974800
IRC: mhroncok

Excluding older builds of packages from Fedora when testing new ones in Copr