fix/unbreak chunks initialized

changes/2862.bugfix.rst

@@ -0,0 +1 @@
+Fix a bug that prevented the number of initialized chunks being counted properly.

docs/user-guide/groups.rst

@@ -140,7 +140,7 @@ property. E.g.::
    No. bytes          : 8000000 (7.6M)
    No. bytes stored   : 1614
    Storage ratio      : 4956.6
-   Chunks Initialized : 0
+   Chunks Initialized : 10
    >>> baz.info
    Type               : Array
    Zarr format        : 3

src/zarr/core/array.py

@@ -117,6 +117,7 @@
     get_pipeline_class,
 )
 from zarr.storage._common import StorePath, ensure_no_existing_node, make_store_path
+from zarr.storage._utils import _relativize_path
 
 if TYPE_CHECKING:
     from collections.abc import Iterator, Sequence
@@ -3737,7 +3738,12 @@ async def chunks_initialized(
     store_contents = [
         x async for x in array.store_path.store.list_prefix(prefix=array.store_path.path)
     ]
-    return tuple(chunk_key for chunk_key in array._iter_chunk_keys() if chunk_key in store_contents)
+    store_contents_relative = [
+        _relativize_path(key, array.store_path.path) for key in store_contents
+    ]
+    return tuple(
+        chunk_key for chunk_key in array._iter_chunk_keys() if chunk_key in store_contents_relative
+    )
 
 
 def _build_parents(

src/zarr/storage/_utils.py

@@ -74,11 +74,60 @@
     """
     Filter out instances of '' and join the remaining strings with '/'.
 
-    Because the root node of a zarr hierarchy is represented by an empty string,
+    Parameters
+    ----------
+    paths : Iterable[str]
+
+    Returns
+    -------
+    str
+
+    Examples
+    --------
+    >>> _join_paths(["", "a", "b"])
+    'a/b'
+    >>> _join_paths(["a", "b", "c"])
+    'a/b/c'
     """
     return "/".join(filter(lambda v: v != "", paths))
 
 
+def _relativize_path(path: str, prefix: str) -> str:
+    """
+    Make a "\"-delimited path relative to some prefix. If the prefix is '', then the path is
+    returned as-is. Otherwise, the prefix is removed from the path as well as the separator
+    string "\".
+
+    If ``prefix`` is not the empty string and ``path`` does not start with ``prefix``
+    followed by a "/" character, then an error is raised.
+
+    Parameters
+    ----------
+    path : str
+        The path to make relative to the prefix.
+    prefix : str
+        The prefix to make relative to.
+
+    Returns
+    -------
+    str
+
+    Examples
+    --------
+    >>> _relativize_paths("", "a/b")
+    'a/b'
+    >>> _relativize_paths("a/b", "a/b/c")
+    'c'
+    """
+    if prefix == "":
+        return path
+    else:
+        _prefix = prefix + "/"
+        if not path.startswith(_prefix):
+            raise ValueError(f"The first component of {path} does not start with {prefix}.")
+        return path.removeprefix(f"{prefix}/")
+
+
 def _normalize_paths(paths: Iterable[str]) -> tuple[str, ...]:
     """
     Normalize the input paths according to the normalization scheme used for zarr node paths.

tests/test_array.py

@@ -387,12 +387,13 @@ async def test_nchunks_initialized(test_cls: type[Array] | type[AsyncArray[Any]]
         assert observed == expected
 
 
-async def test_chunks_initialized() -> None:
+@pytest.mark.parametrize("path", ["", "foo"])
+async def test_chunks_initialized(path: str) -> None:
     """
     Test that chunks_initialized accurately returns the keys of stored chunks.
     """
     store = MemoryStore()
-    arr = zarr.create_array(store, shape=(100,), chunks=(10,), dtype="i4")
+    arr = zarr.create_array(store, name=path, shape=(100,), chunks=(10,), dtype="i4")
 
     chunks_accumulated = tuple(
         accumulate(tuple(tuple(v.split(" ")) for v in arr._iter_chunk_keys()))