Adding upstream repo to my fork question

[Mark Richardson (MarkUoLeeds)]

Hello, I am following the getting started for lfric_apps (from lfric_core.). In the section "Maintaining forks" it shows how to add an upstream repo to my existing clone. I have done this while the branch I am developing is live. Does it matter and , if not, could that reassurance be added to the page? It might be that I do not need the upstream for this exercise but in the long run I'd like to understand the processes.

Page I am reading is https://metoffice.github.io/simulation-systems/WorkingPractices/maintaining_forks.html

[Pierre Siddall (Pierre-siddall)]

Hi Mark Richardson (@MarkUoLeeds),

Thanks for your question, adding an upstream repository while developing on a live branch of your fork is fine
as the addition of a remote repository only serves as a reference for git to know where it should be running
commands (e.g. whether it should be running a pull command from MarkUoLeeds/lfric_apps or MetOffice/lfric_apps).
So providing the upstream keyword to a git command will target the running of a command to the link you provided
during setup. I hope this helps.

Best,
Pierre

[Mark Richardson (MarkUoLeeds)]

Hi Pierre, sort of helpful. I have now looked at ".git/config" and see it has the same entries no matter which branch I switch to (main, stable, develop) in this clone of my fork of lfric_apps.
Thank you for the quick reply.
Mark

[Yaswant Pradhan (yaswant)]

Hi Mark Richardson (@MarkUoLeeds)

The short answer is: Adding an upstream remote (MetOffice/{repo}) to your local clone while you're actively developing on a branch is safe. It only records another repository URL in your local Git config; it does not touch your working tree, index, or current branch. Nothing changes until you explicitly fetch from that remote and then merge or rebase those fetched commits.

For the Simulation Systems workflow specifically, syncing your fork is done per branch, and it's common to sync both stable and main around a release. The web UI's Sync fork button updates the remote fork, while Git commands update your local clone; you can use either depending on what you intend to update.

If you decide you don't need the upstream remote, you can remove or rename it:

git remote remove upstream     # remove
# or
git remote rename upstream metoffice-upstream   # rename for clarity

In summary, adding the upstream remote while your branch is live doesn’t affect your development branch. The only time your branch changes is when you choose to merge or rebase with content fetched from upstream.

Hope that helps.