ncdump error message when unknown filter is used in 4.8.0 could be better...

[edwardhartnett]

When I do an ncdump on a file with an unknown filter, I get an error message in the middle of the ncdump:

netcdf tst_gfs_data_1_zstd_20 {
dimensions:
	grid_xt = 8 ;
	grid_yt = 4 ;
	pfull = 4 ;
	phalf = 5 ;
	time = 1 ;
variables:
	double grid_xt(grid_xt) ;
		grid_xt:cartesian_axis = "X" ;
		grid_xt:long_name = "T-cell longitude" ;
		grid_xt:units = "degrees_E" ;
		grid_xt:_Storage = "contiguous" ;
		grid_xt:_Endianness = "little" ;
		grid_xt:_NoFill = "true" ;
	double lon(grid_xt, grid_yt) ;
		lon:long_name = "T-cell longitude" ;
		lon:units = "degrees_E" ;
		lon:_Storage = "contiguous" ;
		lon:_Endianness = "little" ;
		lon:_NoFill = "true" ;
	double grid_yt(grid_yt) ;
		grid_yt:cartesian_axis = "Y" ;
		grid_yt:long_name = "T-cell latiitude" ;
		grid_yt:units = "degrees_N" ;
		grid_yt:_Storage = "contiguous" ;
		grid_yt:_Endianness = "little" ;
		grid_yt:_NoFill = "true" ;
	double lat(grid_xt, grid_yt) ;
		lat:long_name = "T-cell latitude" ;
		lat:units = "degrees_N" ;
		lat:_Storage = "contiguous" ;
		lat:_Endianness = "little" ;
		lat:_NoFill = "true" ;
	float pfull(pfull) ;
		pfull:_Storage = "contiguous" ;
		pfull:_Endianness = "little" ;
		pfull:_NoFill = "true" ;
	float phalf(phalf) ;
		phalf:_Storage = "contiguous" ;
		phalf:_Endianness = "little" ;
		phalf:_NoFill = "true" ;
	double time(time) ;
		time:_Storage = "contiguous" ;
		time:_Endianness = "little" ;
		time:_NoFill = "true" ;
	float var_0(time, pfull, grid_yt, grid_xt) ;
		var_0:max_abs_compression_error = 42.22f ;
		var_0:nbits = 5 ;
		var_0:_Storage = "chunked" ;
		var_0:_ChunkSizes = 1, 4, 4, 8 ;
		var_0:_Filter = "32015,20" ;
		var_0:_Endianness = "little" ;
		var_0:_NoFill = "true" ;

// global attributes:
		:_NCProperties = "version=2,netcdf=4.8.0,hdf5=1.10.7" ;
		:_SuperblockVersion = 2 ;
		:_IsNetcdf4 = 1 ;
		:_Format = "netCDF-4" ;
NetCDF: HDF error
Location: file vardata.c; line 478
data:

 grid_xt = 0, 1, 100, 101, 200, 201, 300, 301 ;

 lon =
  0, 1, 200, 201,
  2, 3, 202, 203,
  1, 2, 201, 202,
  3, 4, 203, 204,
  100, 101, 300, 301,
  102, 103, 302, 303,
  101, 102, 301, 302,
  103, 104, 303, 304 ;

 grid_yt = 0, 100, 200, 300 ;

 lat =
  0, 1, 200, 201,
  2, 3, 202, 203,
  1, 2, 201, 202,
  3, 4, 203, 204,
  100, 101, 300, 301,
  102, 103, 302, 303,
  101, 102, 301, 302,
  103, 104, 303, 304 ;

 pfull = 0, 100, 200, 300 ;

 phalf = 0, 100, 200, 300, 301 ;

 time = 2 ;

 var_0 =

This is because I am using the zstd filter, and ncdump knows nothing of it since it is not currently installed.

But shouldn't the error message be better? How about something like:
"Unknown HDF5 filter encountered, cannot display data for variable var_0"

[WardF]

Tagging @DennisHeimbigner

[DennisHeimbigner]

We have an NC_ENOFILTER err code that I can use. Or were you referring to a log message?

[DennisHeimbigner]

See PR #2000