Merge pull request #2961 from sfinkens/fix-netcdf-devel

Fix CF writer crashing with netcdf development version

satpy/tests/writer_tests/test_cf.py

@@ -528,12 +528,19 @@ def _assert_encoding_as_expected(self, filename, expected):
             assert f["test-array"].dtype == expected["dtype"]
             assert f["test-array"].encoding["complevel"] == expected["complevel"]
 
-    def test_warning_if_backends_dont_match(self, scene, filename, monkeypatch):
+    @pytest.mark.parametrize(
+        "versions",
+        [
+            {"netCDF4": "1.5.0", "libnetcdf": "4.9.1-development"},
+            {"netCDF4": "1.6.0", "libnetcdf": "invalid-version"}
+        ]
+    )
+    def test_warning_if_backends_dont_match(self, scene, filename, monkeypatch, versions):
         """Test warning if backends don't match."""
         import netCDF4
         with monkeypatch.context() as m:
-            m.setattr(netCDF4, "__version__", "1.5.0")
-            m.setattr(netCDF4, "__netcdf4libversion__", "4.9.1")
+            m.setattr(netCDF4, "__version__", versions["netCDF4"])
+            m.setattr(netCDF4, "__netcdf4libversion__", versions["libnetcdf"])
             with pytest.warns(UserWarning, match=r"Backend version mismatch"):
                 scene.save_datasets(filename=filename, writer="cf")
 

satpy/writers/cf_writer.py

@@ -158,7 +158,7 @@
 
 import numpy as np
 import xarray as xr
-from packaging.version import Version
+from packaging.version import InvalidVersion, Version
 
 from satpy.cf.coords import EPOCH  # noqa: F401 (for backward compatibility)
 from satpy.writers import Writer
@@ -390,8 +390,26 @@ def _backend_versions_match():
 
 def _get_backend_versions():
     import netCDF4
+    libnetcdf_version = _parse_libnetcdf_version(
+        netCDF4.__netcdf4libversion__
+    )
     return {
         "netCDF4": Version(netCDF4.__version__),
-        "libnetcdf": Version(netCDF4.__netcdf4libversion__),
+        "libnetcdf": libnetcdf_version,
         "xarray": Version(xr.__version__)
     }
+
+
+def _parse_libnetcdf_version(version_str):
+    # Make libnetcdf development version compatible with PEP440
+    version_str = version_str.replace("development", "dev")
+    try:
+        return Version(version_str)
+    except InvalidVersion:
+        warnings.warn(
+            f"Unable to parse netcdf-c version {version_str}, "
+            f"using 0.0.0 as fallback",
+            UserWarning,
+            stacklevel=3
+        )
+        return Version("0.0.0")