Build-namelist logic to find the finidat file is fragile and needs to be redone

[ekluzek]

In working on #2008 I'm finding that the logic to fine the finidat file is: complex, hard to understand, fragile, and will require a bunch of duplication. This is another reason for doing #585 which is the long term solution. Although there we should make sure the redesign in python has a better method of getting the finidat files.

This is similar to #549, but slightly different and focussed on just the namelist logic and the namelist default settings for: use_init_interp and init_interp_attributes. This is also related to #2149, as we need to have duplicated lnd_tuning_mode options for all the different clm physics options, as well as the cam options. Right now this is going to require a bunch of duplication.

Definition of Done:

• Improve the error message so it at least gives you a clue on what's wrong...
• Add testing for finidat files to the build-namelist unit tester
• Fix case of finidat files with do_transient_pfts=.true. (example 1979 or 2000 files) so that use_init_interp doesn't need to be true
• Reduce the required attributes to specify each file (see below)
• Implement a better solution inside of the current buildnml or build-namelist?
• Long term: Reimplement build-namelist as in Move CLMBuildNamelist.pm perl code into the python buildnml #585

[ekluzek]

What the error looks like when it happens is this:

Create namelist for component clm
   Calling /glade/work/erik/ctsm_worktrees/ctsm5.2.mksurfdata/cime_config/buildnml
ERROR: Command /glade/work/erik/ctsm_worktrees/ctsm5.2.mksurfdata/bld/build-namelist failed rc=255
out=
err=ERROR : CLM build-namelist::CLMBuildNamelist::setup_logic_initial_conditions() : use_init_interp is NOT synchronized with init_interp_attributes

Which just isn't helpful enough.

[ekluzek]

The other error that can happen is:

use_init_interp is set BUT finidat is NOT, need to set both

which can happen because the user explicitly set use_init_interp and didn't set finidat on their own. Or it can happen because the default settings aren't setup correctly. This should be improved as well.

[ekluzek]

Working on this now as part of #2501 I see some improvements that could be made:

• Remove glc_nec and ic_tod (they are all 10 and 0)
• Possibly use one of ic_ymd and sim_year
• Replace bgc (sp, bgc, fates) for use_cn, use_cndv, use_fates) use_cndv can be removed as part of Start removing BGCDV mode #2141
• use one of use_crop and maxpft

This would reduce the number of attributes needed to specify a finidat file from 15 to 9.

Another part is to remove the duplication of the filenames in the XML and make sure that it's only the init_interp_attributes that are duplicated. In general removing duplication in the XML is a good goal and especially in duplicating the full path name to the files.

[ekluzek]

Adding to this: https://github.com/ESCOMP/CTSM/pull/2821/files#r1797496942

so that 1979 and 2000 finidat files will work with do_transient_pfts=.true.