RuntimError in `tests/test_structure.py::test_ravel_fail` with `dask==2025.3.0`

[GaetanLepage]

Bumping dask to 2025.3.0 leads to tests/test_structure.py::test_ravel_fail to fail with:

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

EDIT: test_persist too.

[lgray]

@GaetanLepage this appears to be some transient error outside of test_ravel_fail. We see it but for different tests in our CI and running again tends to fix.

@martindurant probably has better understand of why this may suddenly be happening?

[lgray]

Ah, this is much more than flaky looking at recent CI runs.

I don't know why we don't run this nightly. Dask changes too quickly these days to feel comfortable without a decent pace of tests.

It also seems acutely related to how testing is done in this package... We don't see problems over in coffea, for instance.

[lgray]

Ah sorry - misread this as dask_awkward==2025.3.0, rather than just dask. Yes dask 2025.3.0 is causing problems. Would recommend pinning < 2025.3.0 for now we'll get it figured out.

Thanks for the catch!

[lgray]

@fjetter just FYI dask-awkward is broken again with dask 2025.3.0.

We should figure out how to coordinate better for the future.

We'll try to get a bisection today so we can point to the relevant PR in dask.

[lgray]

Oddly enough, coffea's tests appear to be completely fine despite all the failed tests here?

[martindurant]

See comments here for more weirdness.

I suspect the "asynchronous Client in a synchronous context" is real and perhaps just more strictness from dask.

[fjetter]

This is almost certainly dask/dask#11790 and it is indeed more strict than before. Are you sure that your test case actually worked before?

See comments #572 (comment) for more weirdness.

this is another error and should only happen on main

[martindurant]

Are you sure that your test case actually worked before

Yes probably: it didn't actually evaluate the graph, only check its keys.

[GaetanLepage]

Thanks for your answers. For context, I am bumping dask to 2025.3.0 in nixpkgs.
You can see in the PR what patches I have made to get everything running:
NixOS/nixpkgs#391973