Pandas deprecation warning when deserializing AxClient JSON

[parrangoiz]

Hi! I'm a new user of Ax and I'm loving the framework, thanks for making this open to everyone! I've been using the Service API to run experiments and save intermediate snapshots to JSON. When deserializing, I get a deprecation warning (emitted by Pandas I believe). I'm using Ax 0.3.7. Here's a simple repro:

from ax.service.ax_client import AxClient
from ax.service.utils.instantiation import ObjectiveProperties

ax_client = AxClient(verbose_logging=False)
ax_client.create_experiment(
    name="test",
    parameters=[{"name": "x", "type": "range", "bounds": [0.0, 1.0]}],
    objectives={"f": ObjectiveProperties(minimize=True)},
)

for i in range(5):
    parameters, trial_index = ax_client.get_next_trial()
    data = {"f": parameters["x"] ** 2}
    ax_client.complete_trial(trial_index=trial_index, raw_data=data)

ax_client.save_to_json_file("test.json")
restored_client = AxClient.load_from_json_file("test.json")

Output:

[Standard information messages]
.../ax/core/data.py:203: FutureWarning: Passing literal json to 'read_json' is deprecated and will be removed in a future version. To read from a literal string, wrap it in a 'StringIO' object.

Seems fairly straightforward, I'd be happy to attempt to fix it unless this is already in the works. I'm not familiar with the codebase yet though, so not sure if there are other places this would have to change other than the offending line in core.data.

[Cesar-Cardoso]

Hello there! Thanks for flagging this. This is a known issue that's been addressed in #2346. It'll go away with the next release of Ax.

[parrangoiz]

Oops, missed that. Thanks!