Unused fates switch that sets up defaults and influences namelist build

[mvdebolskiy]

Brief summary of bug

Unused fates switch that for some reason is used in namelists.

General bug information

CTSM version you are using: ctsm5.4.039

Does this bug cause significantly incorrect results in the model's science? No

Configurations affected: Fates

Details of bug

For whatever reason, there is still a switch:

CTSM/src/utils/clmfates_interfaceMod.F90

Line 76 in f1e0f23

use clm_varctl , only : use_fates_lupft

That is not used anywhere inside or outside fates apart from in ClmBuildNamelist.pm and piped to controlMod

For whatever reason it is used as an attribute in bunch of namelist_defauls entries for fates switches.

Important details of your setup / configuration so we can reproduce the bug

Important output or errors that show the problem

[mvdebolskiy]

@glemieux @rgknox is this switch still needed?

[glemieux]

This is provided to the user as a convenience namelist option that sets use_fates_nocomp, use_fates_luh and use_fates_fixed_biogeog. It was very briefly used in the clmfates_interfacemod at one point so that line noted above can be removed, but it was never meant to be passed to fates.

[slevis-lmwg]

@mvdebolskiy see bld/namelist_files/namelist_definition_ctsm.xml for some documentation on this namelist option.

[mvdebolskiy]

@slevis-lmwg I understand, but in ClmBldNamelists all the thing that are used as attributes in xml entries to get defaults not used in fortran code are $nl_flags and mostly belong to default_settings category, not appearing in the lnd_in. Wen I see a flag in lnd_in, I assume it actually does something in the code.

[samsrabin]

SE meeting: Unfortunately, whether something appears in lnd_in is more or less completely arbitrary. Our instinct is to leave this in as a useful convenience function. Unless: @mvdebolskiy, does this issue affect your problems with creating a NorESM compset? (And is there an issue filed somewhere about that?) Or is it related to #1617?