[Announcement] Release Progress Update

[Jenny Hickson (jennyhickson)]

UM and LFRic Releases

The review process for all the repositories is complete or almost complete, and we are now moving on to migrating them all to GitHub. Once the last review has happened the trunk of each repository will be frozen to enable this process and the upcoming releases will be completed on GitHub. Branches can still be worked on throughout this time, and we will provide guidelines for developers to migrate these after the release.

The repositories we are migrating at this time includes:

• LFRic Apps
• LFRic Core
• UM
• JULES
• UKCA
• SOCRATES
• CASIM
• GCOM
• MOCI

We anticipate the migration process will take another few weeks, thank you for your patience.

Jenny, on behalf of the SSD team

[Paul Leopardi (penguian)]

Thanks for the announcement.

Which software versions are being migrated to GitHub (e.g.) only UM 13.9 or all of UM version 13? How do these versions correspond to science configurations (e.g.) RAL3.2?

Where can I find the documentation on the build process for code that has been migrated to GitHub? How is FCM being used with cloned GitHub repositories?

Are there any GitHub repositories that ACCESS-NRI can use to test and refine the Spack packages that it is using to build (e.g.) the UM? Right now, for ACCESS-AM3, the Spack package recipe uses GitHub for UM and Jules, and MOSRS Subversion for everything else. For all other UM-based models, the Spack package recipe uses only the MOSRS Subversion repository.

[Jenny Hickson (jennyhickson)]

Thanks for the questions.

We are migrating the trunk of each repository which includes the complete MOSRS history, including commits and tags, so the source code will be available at all versions since UM vn9.2. The changes to rose-stem to extract the code from git instead of MOSRS will only be available at the latest release (the upcoming vn14.0 for the UM).

The build system is remaining the same, but source extraction will necessarily change. With rose-stem we are adding an extract step to clone all required GitHub repositories and pointing FCM to compile based on those. The example suites that we maintain will also use this approach, and there will be some documentation available before go live on GitHub. If you are already working with GitHub for some repositories I imagine you'll find very little needs changing.

The MOSRS repositories will continue to exist (with frozen trunks) for some time after the migration, so there will be plenty of time to migrate and test across the systems once the code has been moved.

Hope that helps.

[iboutle]

To answer the top question - there is (deliberately) no correspondence between code versions and science configurations. Each science configuration can be run at multiple code versions, and one code version will support multiple science configurations.

[Paul Leopardi (penguian)]

Thanks for your replies. At ACCESS-NRI we are using Spack to build UM and related executables.

The Spack package recipe for UM currently uses FCM Make but does not use Rose or Cylc. It instead uses a Rose app config file for each supported model (e.g. ACCESS-AM3), but uses configparser to read it directly. Right now for the ACCESS-AM3 model it uses a _dynamic_resource member function to associate a ref variant to a GitHub URL and clone the corresponding repository.

To fully support multiple extract_location{diff} sources, this mechanism would need to be extended, and some way of specifying each cloned repository location would need to be provided, most likely via the

[file:blah]
source=git:https://github.com/ACCESS-NRI/blah

syntax that Ben Fitzpatrick and Mateusz Wojcieszyk describe in their "Future of Workflows Under Git" presentation of 2025-07-02.

[Paul Leopardi (penguian)]

See ACCESS-NRI/access-spack-packages#347