[v3] implement / deprecate zarr.tree

src/zarr/api/asynchronous.py

@@ -493,8 +493,33 @@ async def save_group(
     await asyncio.gather(*aws)
 
 
-async def tree(*args: Any, **kwargs: Any) -> None:
-    raise NotImplementedError
+async def tree(grp: AsyncGroup, expand: bool | None = None, level: int | None = None) -> Any:
+    """Provide a rich display of the hierarchy.
+
+    Parameters
+    ----------
+    grp : Group
+        Zarr or h5py group.
+    expand : bool, optional
+        Only relevant for HTML representation. If True, tree will be fully expanded.
+    level : int, optional
+        Maximum depth to descend into hierarchy.
+
+    Returns
+    -------
+    TreeRepr
+        A pretty-printable object displaying the hierarchy.
+
+    .. deprecated:: 3.0.0
+        `zarr.tree()` is deprecated and will be removed in a future release.
+        Use `group.tree()` instead.
+    """
+    warnings.warn(
+        "zarr.tree() is deprecated and will be removed in a future release. Use group.tree() instead.",
+        DeprecationWarning,
+        stacklevel=2,
+    )
+    return await grp.tree(expand=expand, level=level)
 
 
 async def array(

src/zarr/api/synchronous.py

@@ -155,8 +155,8 @@ def save_group(
     )
 
 
-def tree(*args: Any, **kwargs: Any) -> None:
-    return sync(async_api.tree(*args, **kwargs))
+def tree(grp: Group, expand: bool | None = None, level: int | None = None) -> Any:
+    return sync(async_api.tree(grp._async_group, expand=expand, level=level))
 
 
 # TODO: add type annotations for kwargs

src/zarr/core/group.py

@@ -1449,7 +1449,7 @@ async def tree(self, expand: bool | None = None, level: int | None = None) -> An
         from zarr.core._tree import group_tree_async
 
         if expand is not None:
-            raise NotImplementedError("'expanded' is not yet implemented.")
+            raise NotImplementedError("'expand' is not yet implemented.")
         return await group_tree_async(self, max_depth=level)
 
     async def empty(