Jordan Petridis commented:
We already build the core apps in gnome-build-meta, and buildstream already supports generating flatpaks. Are there any obstacles to using buildstream for the flatpaks of the core apps?
Its kinda weird, cause what we will end up publishing will be different from the manifest in the apps repo which is what Builder and the maintainers are going to be using to be using to build and test their apps. If everybody was using buildstream this wouldn't be much of an issue, but our current developer tooling is mostly around flatpak-builder and bst adoption hasn't been great. I think we should aim for making it as painless as possible for the app maintainers, even if that means the RT would have to maintain a separate build definition (gnome-build-meta) and let the apps continue using their flatpak manifests as their source of truth.
Another option I'm starting to consider is to only build them as flatpaks (and preinstall them as flatpaks in our upcoming OS images). This seems the logical next step to me in the context of GNOME/gnome-build-meta#142
+1, it seems redundant currently to doing it both ways. One issue though, is what would happen to the development/test experience with buildstream (nobody uses it yet, but we shouldn't make the workflow worse). Would this mean that for every change we would have to checkout a flatpak bundle and run that? And if so what would be the required changes in the bst plugin to make this as easier, like flatpak-builder --install or such.