Working with Multiple Repositories#

The repositories covered by these working practices all interact with and have dependencies on each other. This means that changes that affect multiple repositories need handling with extra care.

To think about how the repositories work together it’s useful to think about them as almost concentric circles. The child repositories such as JULES or UKCA sit in the centre and are mostly independent of anything else. The UM is a parent of those repositories and is dependant on changes in it’s own code base and on those in the children. LFRic Apps is then another layer again and is dependant on both the UM physics and the other child repositories. LFRic Apps also utilises the infrastructure in LFRic Core.

This means that changes to the science code in JULES etc will need testing with both the UM and LFRic Apps to check for any interactions. Likewise, changes to the atmosphere code in the UM will require LFRic Apps testing.

../_images/repo_circles.png

Preparing Linked Tickets#

Every repository in a set of linked changes requires a ticket. Guidance on setting these up can be found in Create a Ticket. These tickets will be treated as a group with the same reviewers and committed at the same time.

Do:

  • Make sure every ticket has a cross reference to the others in the set, e.g. um:#1234

  • Use Commonly-Used Keywords to show which other repositories are involved

  • Get the tickets ready for review at the same time

  • Ask for help testing if you don’t have access to all the codebases involved

Important

Code branches in linked tickets will require branching from compatible revisions to ensure they work together.

If working with branches from a release then all repositories will be tagged with suitable keywords, e.g. for UM vn13.0, other repositories are also tagged with um13.0.

For head of trunk revisions make sure that all branches/revisions being used are at least as recent as the versions listed in the _rev parameter of <lfric_apps_trunk>/dependencies.sh, or <um_trunk>/rose-stem/rose-suite.conf.

If in doubt, please contact the Simulation Systems and Deployment Team for advice.

Multi-Repo Testing#

Please see this page for details on how to test multiple repositories together.