From 5d4f44599e511b3eea93bcb6317c82bdf7354926 Mon Sep 17 00:00:00 2001
From: Vincent Gao <gaobing1230@gmail.com>
Date: Fri, 26 Jun 2026 15:54:30 +0200
Subject: [PATCH] Fix scalar array save and load

---
 changes/3469.bugfix.md       |  1 +
 src/zarr/api/asynchronous.py |  4 ++--
 tests/test_api.py            | 16 ++++++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 changes/3469.bugfix.md

diff --git a/changes/3469.bugfix.md b/changes/3469.bugfix.md
new file mode 100644
index 0000000000..eb56e87476
--- /dev/null
+++ b/changes/3469.bugfix.md
@@ -0,0 +1 @@
+Fixed `save_array`, `Group.__setitem__`, and `load` for 0-dimensional arrays.
diff --git a/src/zarr/api/asynchronous.py b/src/zarr/api/asynchronous.py
index 7f185535df..1908a1a11e 100644
--- a/src/zarr/api/asynchronous.py
+++ b/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(
diff --git a/tests/test_api.py b/tests/test_api.py
index 503aeee405..1b4414ae63 100644
--- a/tests/test_api.py
+++ b/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