Hydra 1.2 introduces hydra.sweeper.params. All Hydra Sweepers (BasicSweeper and HPOs) search space will be defined under this config node.

Optuna

For migration, move search space definition from hydra.sweeper.search_space to hydra.sweeper.params. Change the search space definition to be consistent with how you'd override a value from commandline. For example:

Hydra 1.1

hydra:
  sweeper:
    search_space:
      search_space:
        x:
          type: float
          low: -5.5
          high: 5.5
          step: 0.5
        'y':
          type: categorical
          choices:
          - -5
          - 0
          - 5

Hydra 1.2

hydra:
  sweeper:
    params:
      x: range(-5.5, 5.5, step=0.5)
      y: choice(-5, 0, 5)

Check out Optuna Sweeper for more info.