Allow scalar data for zero-dim CoordManager and propagate CoordManager dims in PatchAttrs.update

dascore/core/attrs.py

@@ -239,8 +239,12 @@ def update(self, **kwargs) -> Self:
         new_coords = dict(out.get("coords", {}))
         if isinstance(passed_in_coords, dc.CoordManager):
             new_coords = passed_in_coords.model_dump(exclude_unset=True)
+            out["dims"] = passed_in_coords.dims
 
-        coord_info, attr_info = separate_coord_info(kwargs, dims=self.dim_tuple)
+        dims = out.get("dims", self.dim_tuple)
+        if isinstance(dims, str):
+            dims = tuple(dims.split(",")) if dims else tuple()
+        coord_info, attr_info = separate_coord_info(kwargs, dims=tuple(dims))
         out.update(attr_info)
         # Iterate the coordinate information and update.
         for name, coord_dict in coord_info.items():

dascore/core/coordmanager.py

@@ -818,7 +818,9 @@ def ndim(self):
 
     def validate_data(self, data):
         """Ensure data conforms to coordinates."""
-        data = np.asarray([]) if data is None else data
+        data = np.asarray([]) if data is None else np.asarray(data)
+        if not self.dims and data.shape == ():
+            return data
         if self.shape != data.shape:
             msg = (
                 f"Data array has a shape of {data.shape} which doesnt match "

tests/test_core/test_coordmanager.py

@@ -169,6 +169,19 @@ def test_init_list_range(self):
         out = get_coord_manager(input_dict, dims=list(input_dict))
         assert set(out.dims) == set(input_dict)
 
+    def test_scalar_data_ok_for_no_dims(self):
+        """Ensure scalar data validates for coordinate managers with no dims."""
+        cm = get_coord_manager()
+        out = cm.validate_data(np.array(1.0))
+        assert out.shape == ()
+
+    def test_python_scalar_data_ok_for_no_dims(self):
+        """Ensure python scalars are converted and validate with no dims."""
+        cm = get_coord_manager()
+        out = cm.validate_data(1.0)
+        assert isinstance(out, np.ndarray)
+        assert out.shape == ()
+
     def test_bad_datashape_raises(self, cm_basic):
         """Ensure a bad datashape raises."""
         match = "match the coordinate manager shape"

tests/test_proc/test_proc_coords.py

@@ -673,6 +673,14 @@ def test_coord_summary(self, flat_patch):
         if coords:
             assert set(coords) == set(patch.coords.coord_map)
 
+    def test_squeeze_all_dims_len_one(self, random_patch):
+        """Squeezing a (1, 1) patch should produce scalar patch with no dims."""
+        patch = random_patch.aggregate(dim=None, method="mean", dim_reduce="empty")
+        out = patch.squeeze()
+        assert out.data.shape == ()
+        assert out.dims == ()
+        assert out.attrs.dim_tuple == ()
+
 
 class TestGetCoord:
     """Tests for the get_coord convenience function."""