Silence hypothesis complex warning

src/zarr/core/buffer/core.py

@@ -457,7 +457,10 @@ def __repr__(self) -> str:
         return f"<NDBuffer shape={self.shape} dtype={self.dtype} {self._data!r}>"
 
     def all_equal(self, other: Any) -> bool:
-        return bool((self._data == other).all())
+        # use array_equal to obtain equal_nan=True functionality
+        data, other = np.broadcast_arrays(self._data, other)
+        result = np.array_equal(self._data, other, equal_nan=True)
+        return result
 
     def fill(self, value: Any) -> None:
         self._data.fill(value)

tests/v3/test_array.py

@@ -135,3 +135,22 @@ def test_array_v3_fill_value(store: MemoryStore, fill_value: int, dtype_str: str
 
     assert arr.fill_value == np.dtype(dtype_str).type(fill_value)
     assert arr.fill_value.dtype == arr.dtype
+
+
+@pytest.mark.parametrize("store", ["memory"], indirect=True)
+async def test_array_v3_nan_fill_value(store: MemoryStore) -> None:
+    shape = (10,)
+    arr = Array.create(
+        store=store,
+        shape=shape,
+        dtype=np.float64,
+        zarr_format=3,
+        chunk_shape=shape,
+        fill_value=np.nan,
+    )
+    arr[:] = np.nan
+
+    assert np.isnan(arr.fill_value)
+    assert arr.fill_value.dtype == arr.dtype
+    # all fill value chunk is an empty chunk, and should not be written
+    assert not [a async for a in store.list_prefix("/")]