Preserve all attrs with GroupBy by default. (#7022)

Author: dcherian

doc/whats-new.rst

@@ -65,6 +65,9 @@ Bug fixes
   By `András Gunyhó <https://github.com/mgunyho>`_.
 - Avoid use of random numbers in `test_weighted.test_weighted_operations_nonequal_coords` (:issue:`6504`, :pull:`6961`).
   By `Luke Conibear <https://github.com/lukeconibear>`_.
+- Use ``keep_attrs=True`` in grouping and resampling operations by default (:issue:`7012`).
+  This means :py:attr:`Dataset.attrs` and :py:attr:`DataArray.attrs` are now preserved by default.
+  By `Deepak Cherian <https://github.com/dcherian>`_.
 - ``Dataset.encoding['source']`` now exists when reading from a Path object (:issue:`5888`, :pull:`6974`)
   By `Thomas Coleman <https://github.com/ColemanTom>`_.
 

xarray/core/groupby.py

@@ -662,7 +662,7 @@ def _flox_reduce(self, dim, keep_attrs=None, **kwargs):
         obj = self._original_obj
 
         if keep_attrs is None:
-            keep_attrs = _get_keep_attrs(default=False)
+            keep_attrs = _get_keep_attrs(default=True)
 
         # preserve current strategy (approximately) for dask groupby.
         # We want to control the default anyway to prevent surprises
@@ -1173,6 +1173,9 @@ def reduce(
         if dim is None:
             dim = self._group_dim
 
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=True)
+
         def reduce_array(ar: DataArray) -> DataArray:
             return ar.reduce(
                 func=func,
@@ -1323,6 +1326,9 @@ def reduce(
         if dim is None:
             dim = self._group_dim
 
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=True)
+
         def reduce_dataset(ds: Dataset) -> Dataset:
             return ds.reduce(
                 func=func,

xarray/tests/test_groupby.py

@@ -30,7 +30,7 @@ def dataset():
             "foo": (("x", "y", "z"), np.random.randn(3, 4, 2)),
             "baz": ("x", ["e", "f", "g"]),
         },
-        {"x": ["a", "b", "c"], "y": [1, 2, 3, 4], "z": [1, 2]},
+        {"x": ("x", ["a", "b", "c"], {"name": "x"}), "y": [1, 2, 3, 4], "z": [1, 2]},
     )
     ds["boo"] = (("z", "y"), [["f", "g", "h", "j"]] * 2)