ska3 metapackages

[taldcroft]

Just to capture thoughts here on some metapackages:

• ska3-flight has all Ska3 flight packages (e.g. Ska.engarchive, kadi, etc) specified by version.
• ska3-flight-core has all core Ska3 flight dependencies (e.g. numpy, ipython, scipy, etc), specified by version. It gets generated by some TBD reproducible process. These are all supplied by the defaults channel. We need to see in practice whether there are problems with slightly difference package versions being available for different platforms. This meta-package will be a dependence of ska3-flight using metapackage chaining.

Following may not be needed

• ska3-dev has all the Ska3 internal packages supplied by our conda build process. It is like ska3-flight but does not include the ska3-flight-core dependence nor any version numbers. Let it all (mostly) float!! This could be used in major version updates to ska3-flight-core.
• ska3-pinned could be a way to explicitly capture requirements that can never float. So installing ska3-dev ska3-pinned would result in a working environment which meets the pinning requirements.

[jeanconn]

For metapackage recipes, is the underlying version of the dependency enough, or do we also want to try to lock in build string and build number?

[taldcroft]

Let's just go with the version of the dependency.

[jeanconn]

Which is good, because I'm not entirely sure there is a way to add build strings in these requirements anyway.

[jeanconn]

And I think this is all done in #19 . I'm not sure if at some point the metapackages could be moved to noarch, but they are tiny/quick to rebuild for supported platforms anyway.