Compatibility between leapp and leapp repositories¶
There is a hidden dragon in the split of leapp framework and leapp repositories projects. The development of features and incompatible changes has different speed in both projects. We want to release our projects using semantic versioning and, at the same time, we do not want to release a new version of the project after each merge of a new feature or incompatible change. We rather prefer releasing new versions with changelogs and everything when we agree it‘s worthwhile.
But we need a mechanism to be able to synchronize with other projects, when we
provide new functionality in the upstream (master) branch without the need
of immadiate release of the new version of leapp. For these purposes the
leapp-framework capability is provided in the framework (python-leapp) rpms.
When and how change the capability¶
leapp-framework capability has to be changed in case of any change of
provided API (e.g. change in the leapp standard library) or functionality that
could affect actors in leapp repositories. That includes new features as well
as an actor may depend on that in future, and the leapp-repository package
should be able to specify correct framework version that is needed.
leapp-framework capability uses just
- In case of a change breaking previous functionality (e.g. changed a name of a function) provided by the framework, bump
- In case of a new feature (e.g. new function in stdlib), which doesn‘t affect already existing actors, bump
The value of the capability should be bumped per PR providing all changes. IOW, when a PR implements two compatible/incompatible changes in several commits, the value should be bumped only once!
As well it is recommended to mentioned the value of the capability (when changed) in the commit msg, so it the tracking is easy.
Suggested dependency in leapp-repository rpms¶
We suggest to set dependency on the
leapp-framework capability in any rpm
that contains leapp repositories in this way:
Requires: leapp-framework >= 1.2, leapp-framework < 2
Which means, that you want to install framework of version at least 1.2 but lower than 2 (e.g. 1.99).
There is unfortunately one issue with the above solution. As far as there is just one rpm providing that capability, it‘s ok. The problem occurs on systems where there will be more rpms (of different name) providing the capability. So in case you are able to install e.g. python2-leapp and python3-leapp rpms on the system, you could end up with:
- python2-leapp providing leapp-framework 1.0, and
- python3-leapp providing leapp-framework 3.0
which both are broken for leapp repository and the dependency from the point of rpms is satisfied. This should happen rarely. We suggest you to ensure that you use such repositories where only one of those rpms exists.