Remove from_root

xarray/core/datatree.py

@@ -1241,31 +1241,25 @@ def isomorphic(
     def _matching(
         self,
         other: DataTree,
-        from_root: bool,
         nodes_match: Callable[[DataTree, DataTree], bool],
     ) -> bool:
-        if not self.isomorphic(other, from_root=from_root, strict_names=True):
+        if not self.isomorphic(other, from_root=True, strict_names=True):
             return False
 
         return all(
             nodes_match(node, other_node)
-            for node, other_node in zip(self.subtree, other.subtree)
+            for node, other_node in zip(self.descendants, other.descendants)
         )
 
-    def equals(self, other: DataTree, from_root: bool = True) -> bool:
+    def equals(self, other: DataTree) -> bool:
         """
         Two DataTrees are equal if they have isomorphic node structures, with matching node names,
         and if they have matching variables and coordinates, all of which are equal.
 
-        By default this method will check the whole tree above the given node.
-
         Parameters
         ----------
         other : DataTree
             The other tree object to compare to.
-        from_root : bool, optional, default is True
-            Whether or not to first traverse to the root of the two trees before checking for isomorphism.
-            If neither tree has a parent then this has no effect.
 
         See Also
         --------
@@ -1275,33 +1269,36 @@ def equals(self, other: DataTree, from_root: bool = True) -> bool:
         """
         to_ds = lambda x: x._to_dataset_view(inherited=True, rebuild_dims=False)
         matcher = lambda x, y: to_ds(x).equals(to_ds(y))
-        return self._matching(other, from_root, nodes_match=matcher)
+        if not matcher(self, other):
+            return False
+        return self._matching(other, nodes_match=matcher)
 
-    def identical(self, other: DataTree, from_root=True) -> bool:
+    def identical(self, other: DataTree) -> bool:
         """
         Like equals, but will also check all dataset attributes and the attributes on
         all variables and coordinates, and requires the coordinates are defined at the
         exact same levels of the DataTree hierarchy.
 
-        By default this method will check the whole tree above the given node.
-
         Parameters
         ----------
         other : DataTree
             The other tree object to compare to.
-        from_root : bool, optional, default is True
-            Whether or not to first traverse to the root of the two trees before checking for isomorphism.
-            If neither tree has a parent then this has no effect.
 
         See Also
         --------
         Dataset.identical
         DataTree.isomorphic
         DataTree.equals
         """
+        # include inherited coordinates only at the root; otherwise require that
+        # everything is also defined at the same level
+        self_view = self._to_dataset_view(inherited=True, rebuild_dims=False)
+        other_view = other._to_dataset_view(inherited=True, rebuild_dims=False)
+        if not self_view.identical(other_view):
+            return False
         to_ds = lambda x: x._to_dataset_view(inherited=False, rebuild_dims=False)
         matcher = lambda x, y: to_ds(x).identical(to_ds(y))
-        return self._matching(other, from_root, nodes_match=matcher)
+        return self._matching(other, nodes_match=matcher)
 
     def filter(self: DataTree, filterfunc: Callable[[DataTree], bool]) -> DataTree:
         """

xarray/testing/assertions.py

@@ -116,7 +116,7 @@ def assert_equal(a: DataTree, b: DataTree, from_root: bool = True): ...
 
 
 @ensure_warnings
-def assert_equal(a, b, from_root=True, check_dim_order: bool = True):
+def assert_equal(a, b, check_dim_order: bool = True):
     """Like :py:func:`numpy.testing.assert_array_equal`, but for xarray
     objects.
 
@@ -135,10 +135,6 @@ def assert_equal(a, b, from_root=True, check_dim_order: bool = True):
         or xarray.core.datatree.DataTree. The first object to compare.
     b : xarray.Dataset, xarray.DataArray, xarray.Variable, xarray.Coordinates
         or xarray.core.datatree.DataTree. The second object to compare.
-    from_root : bool, optional, default is True
-        Only used when comparing DataTree objects. Indicates whether or not to
-        first traverse to the root of the trees before checking for isomorphism.
-        If a & b have no parents then this has no effect.
     check_dim_order : bool, optional, default is True
         Whether dimensions must be in the same order.
 
@@ -159,11 +155,7 @@ def assert_equal(a, b, from_root=True, check_dim_order: bool = True):
     elif isinstance(a, Coordinates):
         assert a.equals(b), formatting.diff_coords_repr(a, b, "equals")
     elif isinstance(a, DataTree):
-        if from_root:
-            a = a.root
-            b = b.root
-
-        assert a.equals(b, from_root=from_root), diff_datatree_repr(a, b, "equals")
+        assert a.equals(b), diff_datatree_repr(a, b, "equals")
     else:
         raise TypeError(f"{type(a)} not supported by assertion comparison")
 
@@ -173,11 +165,11 @@ def assert_identical(a, b): ...
 
 
 @overload
-def assert_identical(a: DataTree, b: DataTree, from_root: bool = True): ...
+def assert_identical(a: DataTree, b: DataTree): ...
 
 
 @ensure_warnings
-def assert_identical(a, b, from_root=True):
+def assert_identical(a, b):
     """Like :py:func:`xarray.testing.assert_equal`, but also matches the
     objects' names and attributes.
 
@@ -193,10 +185,6 @@ def assert_identical(a, b, from_root=True):
         The first object to compare.
     b : xarray.Dataset, xarray.DataArray, xarray.Variable or xarray.Coordinates
         The second object to compare.
-    from_root : bool, optional, default is True
-        Only used when comparing DataTree objects. Indicates whether or not to
-        first traverse to the root of the trees before checking for isomorphism.
-        If a & b have no parents then this has no effect.
     check_dim_order : bool, optional, default is True
         Whether dimensions must be in the same order.
 
@@ -220,13 +208,7 @@ def assert_identical(a, b, from_root=True):
     elif isinstance(a, Coordinates):
         assert a.identical(b), formatting.diff_coords_repr(a, b, "identical")
     elif isinstance(a, DataTree):
-        if from_root:
-            a = a.root
-            b = b.root
-
-        assert a.identical(b, from_root=from_root), diff_datatree_repr(
-            a, b, "identical"
-        )
+        assert a.identical(b), diff_datatree_repr(a, b, "identical")
     else:
         raise TypeError(f"{type(a)} not supported by assertion comparison")
 

xarray/tests/test_datatree_mapping.py

@@ -251,9 +251,9 @@ def test_discard_ancestry(self, create_test_datatree):
         def times_ten(ds):
             return 10.0 * ds
 
-        expected = create_test_datatree(modify=lambda ds: 10.0 * ds)["set1"]
+        expected = create_test_datatree(modify=lambda ds: 10.0 * ds)["set1"].copy()
         result_tree = times_ten(subtree)
-        assert_equal(result_tree, expected, from_root=False)
+        assert_equal(result_tree, expected)
 
     def test_skip_empty_nodes_with_attrs(self, create_test_datatree):
         # inspired by xarray-datatree GH262