Set object codec for object arrays

cubed/storage/backend.py

@@ -30,6 +30,16 @@ def open_backend_array(
         from cubed.storage.backends.zarr_python import open_zarr_array
 
         open_func = open_zarr_array
+
+        import numpy as np
+
+        if np.dtype(dtype).hasobject:
+            import numcodecs
+
+            object_codec = numcodecs.Pickle()
+            if "object_codec" not in kwargs:
+                kwargs["object_codec"] = object_codec
+
     elif storage_name == "zarr-python-v3":
         from cubed.storage.backends.zarr_python_v3 import open_zarr_v3_array
 

cubed/tests/test_types.py

@@ -1,5 +1,6 @@
 from numpy.testing import assert_array_equal
 
+import cubed
 import cubed.array_api as xp
 
 
@@ -8,3 +9,8 @@ def test_prod_sum_bool():
     a = xp.ones((2,), dtype=xp.bool)
     assert_array_equal(xp.prod(a).compute(), xp.asarray([1], dtype=xp.int64))
     assert_array_equal(xp.sum(a).compute(), xp.asarray([2], dtype=xp.int64))
+
+
+def test_object_dtype():
+    a = xp.asarray(["a", "b"], dtype=object, chunks=2)
+    cubed.to_zarr(a, store=None)