Dont write _ARRAY_DIMENSIONS to icechunk (#286)

* dont write _ARRAY_DIMENSIONS

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* release note

* change test

* add xarray 2024.10.0 dependency to icechunk CI

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/releases.rst

@@ -59,6 +59,8 @@ Bug fixes
 - Fixed regression in `fill_value` handling for datetime dtypes making virtual
   Zarr stores unreadable (:pull:`206`)
   By `Timothy Hodson <https://github.com/thodson-usgs>`_
+- Fixed bug with writing of `dimension_names` into zarr metadata.
+  (:pull:`286`) By `Tom Nicholas <https://github.com/TomNicholas>`_.
 
 Documentation
 ~~~~~~~~~~~~~

virtualizarr/tests/test_writers/test_icechunk.py

@@ -68,7 +68,7 @@ def test_write_new_virtual_variable(
     # assert dict(arr.attrs) == {"units": "km"}
 
     # check dimensions
-    assert arr.attrs["_ARRAY_DIMENSIONS"] == ["x", "y"]
+    assert arr.metadata.dimension_names == ("x", "y")
 
 
 def test_set_single_virtual_ref_without_encoding(

virtualizarr/writers/icechunk.py

@@ -144,7 +144,6 @@ def write_virtual_variable_to_icechunk(
     # TODO it would be nice if we could assign directly to the .attrs property
     for k, v in var.attrs.items():
         arr.attrs[k] = encode_zarr_attr_value(v)
-    arr.attrs["_ARRAY_DIMENSIONS"] = encode_zarr_attr_value(var.dims)
 
     _encoding_keys = {"_FillValue", "missing_value", "scale_factor", "add_offset"}
     for k, v in var.encoding.items():