!rm -r ~/.gmt/server/earth/earth_relief/earth_relief_15s_p  # Make sure files are not downloaded
from pygmt import which
which(fname=["@N30W120.earth_relief_15s_p.nc", "@N00E000.earth_relief_15s_p.nc"], download="a")

File ~/OSS/gmt/pygmt/pygmt/src/which.py:67, in which(fname, **kwargs)
     62     with lib.virtualfile_out(kind="dataset") as vouttbl:
     63         lib.call_module(
     64             module="which",
     65             args=build_arg_string(kwargs, infile=fname, outfile=vouttbl),
     66         )
---> 67         paths = lib.virtualfile_to_dataset(vfname=vouttbl, output_type="strings")
     69 match paths.size:
     70     case 0:

File ~/OSS/gmt/pygmt/pygmt/clib/session.py:1940, in Session.virtualfile_to_dataset(self, vfname, output_type, column_names, dtype, index_col)
   1937 result = self.read_virtualfile(vfname, kind="dataset").contents
   1939 if output_type == "strings":  # strings output
-> 1940     return result.to_strings()
   1942 result = result.to_dataframe(
   1943     column_names=column_names, dtype=dtype, index_col=index_col
   1944 )
   1945 if output_type == "numpy":  # numpy.ndarray output

File ~/OSS/gmt/pygmt/pygmt/datatypes/dataset.py:156, in _GMT_DATASET.to_strings(self)
    154         if segment.contents.text:
    155             textvector.extend(segment.contents.text[: segment.contents.n_rows])
--> 156 return np.char.decode(textvector) if textvector else np.array([], dtype=str)

File ~/opt/miniconda/envs/pygmt/lib/python3.12/site-packages/numpy/core/defchararray.py:615, in decode(a, encoding, errors)
    572 @array_function_dispatch(_code_dispatcher)
    573 def decode(a, encoding=None, errors=None):
    574     r"""
    575     Calls ``bytes.decode`` element-wise.
    576
   (...)
    612
    613     """
    614     return _to_bytes_or_str_array(
--> 615         _vec_string(a, object_, 'decode', _clean_args(encoding, errors)))

TypeError: string operation on non-string array