ZipStore.list() fails if store not opened + lack of high-level listing API #3846

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