Help modernizing Hydra's Ax Sweeper plugin #5202

Hi Ax team,

I have resumed maintenance of Hydra and am working on bringing the Hydra Ax Sweeper plugin back up to date.

Hydra's Ax Sweeper had been pinned to an old Ax 0.1.x-era dependency for a long time. I now have a PR that updates the plugin to Ax 1.2.4, moves from the deprecated AxClient service API to ax.api.Client, and updates the plugin's supported Python range to 3.11 through 3.14:

• Hydra PR: Modernize Ax Sweeper for Ax 1.2 hydra-ecosystem/hydra#3178
• Tracking issue: Upgrade and modernize Ax Sweeper hydra-ecosystem/hydra#3176

I would appreciate help from Ax maintainers or contributors in reviewing the Hydra PR, especially for any compatibility concerns or Ax-specific behavior I may have missed while modernizing the integration.

I also opened a follow-up issue to collect feedback on which newer Ax features would be useful to expose through Hydra config:

• Feature catch-up discussion: Consider supporting newer Ax features in Ax Sweeper hydra-ecosystem/hydra#3177

Some possibilities I am considering include multi-objective/scalarized objectives, stepped ranges, hierarchical parameters, persistence/resume, generation strategy knobs, tracking metrics, and Ax-native early stopping.

Specific feedback that would be useful:

• Please comment on the Hydra feature catch-up issue with which newer Ax features you think are most worth exposing in Hydra.
• Would anyone from the Ax side be willing to review the Hydra PR?
• Would anyone from the Ax side like to lead the Ax Sweeper plugin modernization? I can help with Hydra-specific integration, config, packaging, and release issues.

Thanks!