Where can I (should I) add a temp logical in LFRic? #604

^{Originally posted by MichaelWhitall March 18, 2026}
Hi all,

I have a minor bug-fix that I want to lodge in lfric_apps, affecting the PC2 cloud-scheme (the final item in the bullet-list on this issue page: MetOffice/lfric_apps#243). I think in the past it would've been said, if it clearly fixes a bug, just change the code without using any switches as noone will mind a KGO-change for that. But as we get ever-closer to having a frozen and highly-tuned LFRic GC6, I'm guessing that's no-longer the case? In the UM I always ended up having to lodge cloud-scheme bug-fixes under "temporary logicals", because they usually cause a small change in cloud radiative forcing (which is something that has to be finely tuned in the climate model and so mustn't be changed in a frozen configuration).

What's the process for lodging this sort of bug-fix in lfric_apps? I've found the old UM science_fixes_mod still exists in lfric_apps, but could be retired as currently um_physics_init just sets the relevant logicals to true; none of them are in a namelist. Should I just add a switch to toggle on/off the bug in the LFRic cloud namelist? Or does lfric_apps have its own equivalent to temp logicals somewhere that I've missed?

Cheers!
Mike