NetCDF 4.10.0: compound type with enum: ncdump cannot read a file generated by ncgen.

[Alexander-Barth]

I am try to implement NetCDF compound data types in the julia package NCDatasets.jl.

I came across a strange issue where ncdump does not accept the NetCDF file generated by ncgen.
ncgen is given the following CDL:

netcdf weather_data {
types:
  byte enum cloud_t {Clear = 0, Cumulonimbus = 1, Stratus = 2, Overcast = 3};

  compound obs_t {
    float temperature;
    int humidity;
    cloud_t sky_condition;  // Nested Enum
  };

dimensions:
  station = 3;

variables:
  obs_t weather_reports(station);

data:
  weather_reports =
    {22.5, 65, Clear},
    {18.0, 90, Cumulonimbus},
    {15.4, 82, Overcast};
}

Note the nested enum. ncgen seem to be work fine

ncgen -o compound_enum_issue.nc compound_enum_issue.cdl

but ncdump compound_enum_issue.nc fails with:

netcdf compound_enum_issue {                                                                                                                                                 
types:                                                                                                                                                                       
  byte enum cloud_t {Clear = 0, Cumulonimbus = 1, Stratus = 2, Overcast = 3} ;                                                                                               
  compound obs_t {                                                                                                                                                           
    float temperature ;                                                                                                                                                      
    int humidity ;                                                                                                                                                           
    cloud_t sky_condition ;                                                                                                                                                  
  }; // obs_t                                                                                                                                                                
dimensions:                                                                                                                                                                  
        station = 3 ;                                                                                                                                                        
variables:                                                                                                                                                                   
        obs_t weather_reports(station) ;                                                                                                                                     
data:                                                                                                                                                                        
                                                                                                                                                                             
NetCDF: Invalid argument
Location: file dumplib.c; fcn ncenum_typ_tostring line 959
weather_reports = {22.5, 65, Clear}, {0, 5915024, Clear},

Only the first value is correct.

I am using netcdf version 4.10.0 distributed by julia on Linux.
I have similar issue with other NetCDF version installed on my system.

Maybe ncgen did not create correctly data in the first place.
Or do you see a problem with my CDL?

[Alexander-Barth]

I have the same issue when I write the data in julia. The first element is fine, but the others are wrong.

If I change byte enum cloud_t into int enum cloud_t the issue disappears, which suggests that this could be an alignment issue.