Fix zarr.save for given path and multiple args arrays (zarr-developers#3127)

* test and fix path argument in save_group

* add tests for load_array

* Revert "add tests for load_array" partially

This reverts commit 2d0f6e9 partially.

* document changes

Author: brokkoli71

changes/3127.bugfix.rst

@@ -0,0 +1,2 @@
+When `zarr.save` has an argument `path=some/path/` and multiple arrays in `args`, the path resulted in `some/path/some/path` due to using the `path`
+argument twice while building the array path. This is now fixed.

src/zarr/api/asynchronous.py

@@ -505,13 +505,12 @@ async def save_group(
         raise ValueError("at least one array must be provided")
     aws = []
     for i, arr in enumerate(args):
-        _path = f"{path}/arr_{i}" if path is not None else f"arr_{i}"
         aws.append(
             save_array(
                 store_path,
                 arr,
                 zarr_format=zarr_format,
-                path=_path,
+                path=f"arr_{i}",
                 storage_options=storage_options,
             )
         )

tests/test_api.py

@@ -229,22 +229,23 @@ async def test_open_group_unspecified_version(
 @pytest.mark.parametrize("store", ["local", "memory", "zip"], indirect=["store"])
 @pytest.mark.parametrize("n_args", [10, 1, 0])
 @pytest.mark.parametrize("n_kwargs", [10, 1, 0])
-def test_save(store: Store, n_args: int, n_kwargs: int) -> None:
+@pytest.mark.parametrize("path", [None, "some_path"])
+def test_save(store: Store, n_args: int, n_kwargs: int, path: None | str) -> None:
     data = np.arange(10)
     args = [np.arange(10) for _ in range(n_args)]
     kwargs = {f"arg_{i}": data for i in range(n_kwargs)}
 
     if n_kwargs == 0 and n_args == 0:
         with pytest.raises(ValueError):
-            save(store)
+            save(store, path=path)
     elif n_args == 1 and n_kwargs == 0:
-        save(store, *args)
-        array = zarr.api.synchronous.open(store)
+        save(store, *args, path=path)
+        array = zarr.api.synchronous.open(store, path=path)
         assert isinstance(array, Array)
         assert_array_equal(array[:], data)
     else:
-        save(store, *args, **kwargs)  # type: ignore [arg-type]
-        group = zarr.api.synchronous.open(store)
+        save(store, *args, path=path, **kwargs)  # type: ignore [arg-type]
+        group = zarr.api.synchronous.open(store, path=path)
         assert isinstance(group, Group)
         for array in group.array_values():
             assert_array_equal(array[:], data)
@@ -384,8 +385,8 @@ def test_array_order_warns(order: MemoryOrder | None, zarr_format: ZarrFormat) -
 #     assert "LazyLoader: " in repr(loader)
 
 
-def test_load_array(memory_store: Store) -> None:
-    store = memory_store
+def test_load_array(sync_store: Store) -> None:
+    store = sync_store
     foo = np.arange(100)
     bar = np.arange(100, 0, -1)
     save(store, foo=foo, bar=bar)