Fix distributed.Client.compute applied to DataArray

Author: Guido Imperiale

doc/whats-new.rst

@@ -55,8 +55,11 @@ Bug fixes
   due to a ``datetime`` issue in NumPy (:issue:`2334`).
   By `Graham Inggs <https://github.com/ginggs>`_.
 - Fixed bug in ``combine_by_coords()`` causing a `ValueError` if the input had
-  an unused dimension with coordinates which were not monotonic (:issue`3150`).
+  an unused dimension with coordinates which were not monotonic (:issue:`3150`).
   By `Tom Nicholas <http://github.com/TomNicholas>`_.
+- Fixed crash when applying ``distributed.Client.compute()`` to a DataArray
+  (:issue:`3171`). By `Guido Imperiale <https://github.com/crusaderky>`_.
+
 
 .. _whats-new.0.12.3:
 

xarray/core/utils.py

@@ -462,12 +462,22 @@ def __repr__(self: Any) -> str:
 class ReprObject:
     """Object that prints as the given value, for use with sentinel values.
     """
+    __slots__ = ('_value', )
+
     def __init__(self, value: str):
         self._value = value
 
     def __repr__(self) -> str:
         return self._value
 
+    def __eq__(self, other) -> bool:
+        if isinstance(other, ReprObject):
+            return self._value == other._value
+        return False
+
+    def __hash__(self) -> int:
+        return hash((ReprObject, self._value))
+
 
 @contextlib.contextmanager
 def close_on_error(f):

xarray/tests/test_utils.py

@@ -181,6 +181,19 @@ def test_repr_object():
     assert repr(obj) == 'foo'
 
 
+def test_repr_object_magic_methods():
+    o1 = utils.ReprObject('foo')
+    o2 = utils.ReprObject('foo')
+    o3 = utils.ReprObject('bar')
+    o4 = 'foo'
+    assert o1 == o2
+    assert o1 != o3
+    assert o1 != o4
+    assert hash(o1) == hash(o2)
+    assert hash(o1) != hash(o3)
+    assert hash(o1) != hash(o4)
+
+
 def test_is_remote_uri():
     assert utils.is_remote_uri('http://example.com')
     assert utils.is_remote_uri('https://example.com')