Description:

Previously, the check_attribute_value_r4/r8 subroutines simply returned if the attribute (i.e FillValue, add_offset, scale_factor) in the given netcdf file was a NaN (ret_spvalR4 /= ret_spvalR4)

They did not check that the attribute value in the state was also a NaN and therefore matched, which is the purpose of these subroutines

This PR adds an check to see if the attribute value in the state is also a NaN, and if it isn't, errors out with the appropriate message

Fixes issue

Partial fix for issue #970
Updated fix for old, closed issue #323

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Documentation changes needed?

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

Tests

Please describe any tests you ran to verify your changes.

Ran ROMS_Rutgers with and without debugging flags (gfort and intel)
When output_priorinf_sd.nc has NaN as the FillValue, it errors out in the new error check

 ERROR FROM:
  source : io_filenames_mod.f90
  routine: check_attribute_value_r4
  message:   variable attribute, _FillValue in state   9.99999993E+36  does not match _FillValue   NaN  in output_priorinf_sd.nc

When output_priorinf_sd.nc does not have NaN as the FillValue, runs successfully as expected

Checklist for merging

• Updated changelog entry
• Documentation updated
• Update conf.py

Checklist for release

• Merge into main
• Create release from the main branch with appropriate tag
• Delete feature-branch

Testing Datasets

• Dataset needed for testing available upon request
• Dataset download instructions included
• No dataset needed

3 member test case at /glade/work/masmith/DART11.14.2/DART/models/ROMS_rutgers/bug_test
This dir has output_priorinf_sd.nc.NAN that uses NaN as FillValue