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Array.read_only incorrect #2949
Description
import zarr
import zarr.storage
store = zarr.storage.MemoryStore()
zarr.create((100,), store=store, zarr_format=2, path="a")
arr = zarr.open_array(store=store, path="a", zarr_format=2, mode="r")
print(arr.read_only)
# FalseGiven the mode is "r", I think .read_only should return True?
Activity
d-v-b commentedon Apr 3, 2025
In zarr-python 3, arrays and groups don't have their own read / write permission model, instead all of that is handled by the storage layer.
Thus the
read_onlyproperty was added for backwards compatibility with v2, and it doesn't do what you would expect -- it reports whether the array is backed by a read-only store.. So in your example, because you are re-using a store instance, it keeps its original mode (which is probablya). I agree that this is confusing.dstansby commentedon Apr 3, 2025
Hmm, in that case should passing a mode to
open_arrayraise an exception, when the passed mode is different to the mode the store is open with?d-v-b commentedon Apr 3, 2025
i believe
open_arrayhas amodeparameter for backwards compatibility reasons. Since we are controlling access modes with the storage layer, IMO it doesn't make sense to pretend that it's also controlled by the array / group layer, and we should deprecate themodekeyword argument.dstansby commentedon Apr 3, 2025
👍 - I think it's pretty bad that it silently does nothing at the moment!