coords refactor: preserve attrs

Author: dcherian

xarray/groupers.py

@@ -39,9 +39,11 @@
 def _coordinates_from_variable(variable: Variable) -> Coordinates:
     from xarray.core.indexes import create_default_index_implicit
 
+    (name,) = variable.dims
     new_index, index_vars = create_default_index_implicit(variable)
     indexes = {k: new_index for k in index_vars}
     new_vars = new_index.create_variables()
+    new_vars[name].attrs = variable.attrs
     return Coordinates(new_vars, indexes)