Don't skip for resampling

Author: dcherian

xarray/core/groupby.py

@@ -414,8 +414,9 @@ def group_as_index(self) -> pd.Index:
 
     @property
     def can_squeeze(self) -> bool:
+        is_resampler = isinstance(self.grouper, TimeResampleGrouper)
         is_dimension = self.group.dims == (self.group.name,)
-        return is_dimension and self.is_unique_and_monotonic
+        return not is_resampler and is_dimension and self.is_unique_and_monotonic
 
 
 @dataclass

xarray/tests/test_groupby.py

@@ -1786,6 +1786,10 @@ def test_resample_first(self):
         times = pd.date_range("2000-01-01", freq="6h", periods=10)
         array = DataArray(np.arange(10), [("time", times)])
 
+        # resample to same frequency
+        actual = array.resample(time="6h").first()
+        assert_identical(array, actual)
+
         actual = array.resample(time="1D").first()
         expected = DataArray([0, 4, 8], [("time", times[::4])])
         assert_identical(expected, actual)