Squahs: multi-grouper propagate attrs

Author: dcherian

xarray/core/groupby.py

@@ -426,12 +426,16 @@ def factorize(self) -> EncodedGroups:
         )
         dim_name = "stacked_" + "_".join(str(grouper.name) for grouper in groupers)
 
+        coords = Coordinates.from_pandas_multiindex(midx, dim=dim_name)
+        for grouper in groupers:
+            coords.variables[grouper.name].attrs = grouper.group.attrs
+
         return EncodedGroups(
             codes=first_codes.copy(data=_flatcodes),
             full_index=full_index,
             group_indices=_codes_to_group_indices(_flatcodes.ravel(), len(full_index)),
             unique_coord=Variable(dims=(dim_name,), data=midx.values),
-            coords=Coordinates.from_pandas_multiindex(midx, dim=dim_name),
+            coords=coords,
         )