Support the new compression argument in netCDF4 > 1.6.0

xarray/backends/netCDF4_.py

@@ -6,6 +6,7 @@
 from contextlib import suppress
 
 import numpy as np
+from packaging.version import Version
 
 from .. import coding
 from ..coding.variables import pop_to
@@ -242,13 +243,21 @@ def _extract_nc4_variable_encoding(
         "shuffle",
         "_FillValue",
         "dtype",
+        "compression",
     }
     if lsd_okay:
         valid_encodings.add("least_significant_digit")
     if h5py_okay:
-        valid_encodings.add("compression")
         valid_encodings.add("compression_opts")
 
+    if backend == "netCDF4" and has_netcdf4:
+        # if using netCDF4 check the versions are updated enough for supporting the new
+        # compression
+        if Version(netCDF4.__version__) < Version("1.6.0") or Version(
+            netCDF4.getlibversion().split(" ")[0]
+        ) < Version("4.9.0"):
+            valid_encodings.remove("compression")
+
     if not raise_on_invalid and encoding.get("chunksizes") is not None:
         # It's possible to get encoded chunksizes larger than a dimension size
         # if the original file had an unlimited dimension. This is problematic

xarray/tests/test_backends.py

@@ -4888,6 +4888,21 @@ def test_extract_nc4_variable_encoding(self):
         encoding = _extract_nc4_variable_encoding(var, unlimited_dims=("x",))
         assert {} == encoding
 
+    @requires_netCDF4
+    def test_extract_nc4_variable_encoding_netcdf4(self, monkeypatch):
+        # New netCDF4 1.6.0 compression argument.
+        var = xr.Variable(("x",), [1, 2, 3], {}, {"compression": "szlib"})
+        _extract_nc4_variable_encoding(var, backend="netCDF4", raise_on_invalid=True)
+        # Check that fails for older versions
+        import netCDF4
+
+        with monkeypatch.context() as m:
+            m.setattr(netCDF4, "__version__", "1.5.0")
+            with pytest.raises(ValueError):
+                _extract_nc4_variable_encoding(
+                    var, backend="netCDF4", raise_on_invalid=True
+                )
+
     def test_extract_h5nc_encoding(self):
         # not supported with h5netcdf (yet)
         var = xr.Variable(("x",), [1, 2, 3], {}, {"least_sigificant_digit": 2})