fix: guard against None version in module_available

xarray/namedarray/utils.py

@@ -60,6 +60,9 @@ def module_available(module: str, minversion: str | None = None) -> bool:
     if minversion is not None:
         version = importlib.metadata.version(module)
 
+        if version is None:
+            return False
+
         return Version(version) >= Version(minversion)
 
     return True

xarray/tests/test_namedarray.py

@@ -18,7 +18,7 @@
     _ShapeType_co,
 )
 from xarray.namedarray.core import NamedArray, from_array
-from xarray.namedarray.utils import fake_target_chunksize
+from xarray.namedarray.utils import fake_target_chunksize, module_available
 from xarray.tests import requires_cftime
 
 if TYPE_CHECKING:
@@ -666,3 +666,26 @@ def test_fake_target_chunksize_cftime() -> None:
 
     assert faked_chunksize == 73
     assert dtype == np.float64
+
+
+def test_module_available_version_none() -> None:
+    """module_available should return False gracefully when metadata.version returns None."""
+    import importlib.metadata as _metadata
+
+    original_version = _metadata.version
+
+    def mock_version(name: str) -> str | None:
+        if name == "packaging":
+            return None
+        return original_version(name)
+
+    _metadata.version = mock_version
+    try:
+        assert module_available("packaging", minversion="1.0.0") is False
+    finally:
+        _metadata.version = original_version
+
+
+def test_module_available_valid() -> None:
+    """module_available should return True for an installed module with version check."""
+    assert module_available("packaging", minversion="0.0.1") is True