Zarr version
v3.0.2
Numcodecs version
v.0.15.1
Python Version
3.13
Operating System
Linux
Installation
uv add zarr
Description
When updating attributes via the z.update_attributes function, existing attributes get deleted instead of merged.
This is wrongly stated by the docs.
See code in zarr.core.array.py -> AsyncArray.update_attributes:
...
Notes
-----
- This method is asynchronous and should be awaited.
- The updated attributes will be merged with existing attributes, and any conflicts will be
overwritten by the new values.
"""
# metadata.attributes is "frozen" so we simply clear and update the dict
self.metadata.attributes.clear()
self.metadata.attributes.update(new_attributes)
# Write new metadata
await self._save_metadata(self.metadata)
return selfI think self.metadata.attributes.clear() just delete everything from the dictionary
Steps to reproduce
import zarr
z = zarr.create(10, store="data.zarr", overwrite=True)
z.attrs["a"] = []
z.attrs["b"] = 3
print(dict(z.attrs))
z.update_attributes({"a": [3, 4], "c": 4})
print(dict(z.attrs))Outputs:
$ uv run repro.py
{'a': [], 'b': 3}
{'a': [3, 4], 'c': 4}Additional output
No response
Zarr version
v3.0.2
Numcodecs version
v.0.15.1
Python Version
3.13
Operating System
Linux
Installation
uv add zarr
Description
When updating attributes via the
z.update_attributesfunction, existing attributes get deleted instead of merged.This is wrongly stated by the docs.
See code in zarr.core.array.py -> AsyncArray.update_attributes:
... Notes ----- - This method is asynchronous and should be awaited. - The updated attributes will be merged with existing attributes, and any conflicts will be overwritten by the new values. """ # metadata.attributes is "frozen" so we simply clear and update the dict self.metadata.attributes.clear() self.metadata.attributes.update(new_attributes) # Write new metadata await self._save_metadata(self.metadata) return selfI think
self.metadata.attributes.clear()just delete everything from the dictionarySteps to reproduce
Outputs:
$ uv run repro.py {'a': [], 'b': 3} {'a': [3, 4], 'c': 4}Additional output
No response