Should the default `distribution` be bumped from `bionic` to `focal` now?

[andreasabel]

Should the default distribution be bumped from bionic to focal now?

I don't know what the policy is here, but ubuntu-18.04 is discontinued as virtual environment by GHA now, and maybe that points to also upgrade here?

[phadej]

I don't know what the policy is here, but ubuntu-18.04

You are confusing the host environment and the docker image the CI is run in. The host is already ubuntu-20.04. The CI image can stay at 18.04 as long as it's still alive.

Using 20.04 CI would mean dropping support for GHC-7, as bindists are not available at hvr-ppa nor through ghcup for that and newer distributions. That's the reason to stay at 18.04 for as long as possible.

EDIT: As CI tool, I won't push ecosystem to drop support for older GHCs, when there are virtually no users, we can drop the support.

[andreasabel]

You are confusing the host environment and the docker image the CI is run in.

Na, I didn't.

Using 20.04 CI would mean dropping support for GHC-7, as bindists are not available at hvr-ppa

Well, I thought 20.04 was the last version supported by hvr-ppa. Turns out the story is more complicated:

• focal seems to have the major GHC version for 7.0 7.2 7.4 7.10, but misses 7.6 and 7.8: https://launchpad.net/~hvr/+archive/ubuntu/ghc?field.series_filter=focal
• bionic has all the latest GHC 7 major versions: https://launchpad.net/~hvr/+archive/ubuntu/ghc?field.series_filter=bionic
• xenial even has all the minor version: https://launchpad.net/~hvr/+archive/ubuntu/ghc?field.series_filter=xenial

The CI image can stay at 18.04 as long as it's still alive.

I was worried that we would then test against old versions of the system libraries. Packages break when confronted with newer system libraries, and the CI would be oblivious to that. Isn't this a problem?

[phadej]

Isn't this a problem?

I don't know which problem is worse. You can pick your devil. For me it's easier to stick to status quo.

[andreasabel]

Alright, fair enough.

I can easily workaround this by remembering to put distribution: focal/jammy into my cabal.haskell-ci.

[andreasabel]

@phadej wrote:

Using 20.04 CI would mean dropping support for GHC-7, as bindists are not available at hvr-ppa nor through ghcup for that and newer distributions. That's the reason to stay at 18.04 for as long as possible.

Still possible.
Though, let me document that now we are stuck with actions/checkout@v3 because v4 decided to move to node20 which is not supported by bionic as it needs glibc-2.28 but bionic has 2.27.

Refs:

• Update default runtime to node20 actions/checkout#1436
• https://github.com/agda/fix-whitespace/actions/runs/6078025441/job/16488643153 : v4 fails on bionic
• https://repology.org/project/glibc/versions