Fix save/load for scalar arrays

changes/3469.bugfix.md

@@ -0,0 +1 @@
+Fixed `save_array`, `Group.__setitem__`, and `load` for 0-dimensional arrays.

src/zarr/api/asynchronous.py

@@ -304,7 +304,7 @@ async def load(
 
     obj = await open(store=store, path=path, zarr_format=zarr_format)
     if isinstance(obj, AsyncArray):
-        return await obj.getitem(slice(None))
+        return await obj.getitem(Ellipsis)
     else:
         raise NotImplementedError("loading groups not yet supported")
 
@@ -482,7 +482,7 @@ async def save_array(
         overwrite=overwrite,
         **kwargs,
     )
-    await new.setitem(slice(None), arr)
+    await new.setitem(Ellipsis, arr)
 
 
 async def save_group(

tests/test_api.py

@@ -396,6 +396,22 @@ def test_save(store: Store, n_args: int, n_kwargs: int, path: None | str) -> Non
         assert group.nmembers() == n_args + n_kwargs
 
 
+@pytest.mark.parametrize(
+    "data",
+    [
+        np.array(42, dtype=np.int64),
+        np.array("teststr", dtype=np.bytes_),
+    ],
+)
+@pytest.mark.filterwarnings("ignore::zarr.errors.UnstableSpecificationWarning")
+def test_group_setitem_loads_scalar_arrays(sync_store: Store, data: np.ndarray) -> None:
+    root = zarr.open_group(store=sync_store)
+    root["test"] = data
+
+    assert_array_equal(root["test"][...], data)
+    assert_array_equal(zarr.load(store=sync_store, path="test"), data)
+
+
 def test_save_errors() -> None:
     with pytest.raises(ValueError, match="at least one array must be provided"):
         # no arrays provided