Active attributes

[AndersJensen-NOAA]

@grantfirl @dustinswales

These active attributes (see example below) are no fun for developers since they will cause a segmentation fault if the variable is allocated and called for in a microphysics scheme, but not active for that scheme. The resulting segmentation fault provides little help or information finding the issue. Additionally, these variables are activated using the scheme long names, which makes them hard to find when searching code. Given optional arguments, are the active attributes even needed?

Example:

fv3atm/ccpp/data/CCPP_typedefs.meta

Line 1131 in 2c902a6

active = (control_for_microphysics_scheme == identifier_for_gfdl_microphysics_scheme .or. control_for_microphysics_scheme == identifier_for_thompson_microphysics_scheme .or. control_for_microphysics_scheme == identifier_for_nssl_microphysics_scheme)

I suggest one of the following changes:

1. Activate variables using the imp_physics number for easy code searches
2. Remove these active attributes since they are redundant with optional arguments
3. Make it obviously clear to developers that they need to check meta data files for active attributes