Pass node path to tokenize in open_datatree (#10100)

* pass node path to tokenize

* whats new

---------

Co-authored-by: Deepak Cherian <dcherian@users.noreply.github.com>

Author: slevang

doc/whats-new.rst

@@ -64,7 +64,8 @@ Bug fixes
   Haacker <https://github.com/j-haacker>`_.
 - Fix ``isel`` for multi-coordinate Xarray indexes (:issue:`10063`, :pull:`10066`).
   By `Benoit Bovy <https://github.com/benbovy>`_.
-
+- Fix dask tokenization when opening each node in :py:func:`xarray.open_datatree`
+  (:issue:`10098`, :pull:`10100`). By `Sam Levang <https://github.com/slevang>`_.
 
 Documentation
 ~~~~~~~~~~~~~

xarray/backends/api.py

@@ -455,6 +455,7 @@ def _datatree_from_backend_datatree(
                     inline_array,
                     chunked_array_type,
                     from_array_kwargs,
+                    node=path,
                     **extra_tokens,
                 )
                 for path, [node] in group_subtrees(backend_tree)

xarray/tests/test_backends_datatree.py

@@ -543,6 +543,11 @@ def test_open_datatree_chunks(self, tmpdir, simple_datatree) -> None:
         with open_datatree(filepath, engine="zarr", chunks=chunks) as tree:
             xr.testing.assert_identical(tree, original_tree)
             assert_chunks_equal(tree, original_tree, enforce_dask=True)
+            # https://github.com/pydata/xarray/issues/10098
+            # If the open tasks are not give unique tokens per node, and the
+            # dask graph is computed in one go, data won't be uniquely loaded
+            # from each node.
+            xr.testing.assert_identical(tree.compute(), original_tree)
 
     def test_open_groups(self, unaligned_datatree_zarr) -> None:
         """Test `open_groups` with a zarr store of an unaligned group hierarchy."""