ZipStore.list() fails if store not opened + lack of high-level listing API

[kulvait]

Zarr version

v3.1.6 not fixed in 19a383f

Numcodecs version

v0.16.1

Python Version

3.12

Operating System

Linux

Installation

mamba, bug confirmed in latest Git of the project 19a383f

Description

ZipStore.list() uses _lock and _zf
but does not ensure the store is opened
leads to:
AttributeError: 'ZipStore' object has no attribute '_lock' when underlying store is not opened
I do not know if the behavior affects other types of stores.

Expected behavior

list() should ensure the store is opened (similar to _get()), e.g. by calling _sync_open() if needed.

Question

I’m not sure if this affects other store implementations as well, or only ZipStore.

Enhancement / API suggestion

Currently list() exposes raw storage keys (chunks, metadata), which is often not very useful at user level.

It would be helpful to have a higher-level API that lists logical Zarr objects (groups/arrays), for example:

zarr.list_nodes(store)

Steps to reproduce

import zarr
import zarr, asyncio

store = zarr.storage.ZipStore("data.zip", mode="r")

async def main():
return [k async for k in store.list()]

asyncio.run(main())

Additional output

No response