RuntimeError: Attempting to use an asynchronous Client in a synchronous context of `dask.compute`

[GaetanLepage]

Describe the issue:

When bumping dask to 2025.3.0, almost all tests in those files

tests/model_selection/test_incremental.py
tests/model_selection/test_successive_halving.py
tests/model_selection/test_hyperband.py

sarted failing with:

RuntimeError: Attempting to use an asynchronous Client in a synchronous context of `dask.compute`

Minimal Complete Verifiable Example:

$ pytest

Anything else we need to know?:

Environment:

• Dask version: 2025.3.0
• Python version: 3.12
• Operating System: NixOS
• Install method (conda, pip, source): nix

[TomAugspurger]

@stsievert any chance you could take a look at this?

The immediate error is from us using dask.persist(...) instead of client.persist(...) in hyperband. That's relatively easy to fix.

However, there's been some changes in distributed to disallow persisting collections of Futures, so client.persist({0: Future}) doesn't work anymore. I haven't been able to spot an easy fix yet :/