Random package install failures in MacOS CI actions

[mooreryan]

So I know this won't be a very useful issue description, but on multiple actions across multiple repositories, I will randomly get failures on the MacOS.

For example, I will have a step in the action like this...

opam exec -- opam install . --jobs 1 --deps-only --with-doc --with-test

And there will often be a random package install failure e.g.,

┌─ The following actions failed
│ λ build ppxlib 0.24.0
└─ 

Generally it will be a different package that will fail to install each time the action is run. Often, if I rerun the action once or twice it will clear up any problems.

I'm having trouble reproducing this issue as the same action will be totally fine for many commits/runs and then it will randomly fail a couple of times, then be totally fine for the next few runs.

I'm wondering if anyone else has run into this and if so, is there a way to fix it other than just re-running failed actions?

[smorimoto]

Maybe you are enabling the dune cache? The current dune 2 is buggy with the dune cache, which is completely fixed in the upcoming dune 3, and that's why we don't enable the dune cache by default at the moment.

[smorimoto]

Related PRs:

• Add a new implementation of the shared cache and start using it dune#4443
• Remove the old cache library and cache daemon dune#4465
• Update Dune cache documentation dune#4484
• Clean up Dune cache testsuite dune#4498
• [stdune] Remove daemonize dune#4576

[mooreryan]

Thanks, I will take a look at that and report back!

[smorimoto]

Resolved with ocaml/opam-repository#20758.

[mooreryan]

I'm not sure this issue is actually resolved. When using macOS actions, I still get similar problems unless I set dune-cache: false. Note that I'm using the v2 of the setup-ocaml action, and the project is using dune 3.5.

(Edit: just to be clear, when I use dune-cache: false, it does when using macOS, but using dune-cache: true gives the same type of errors.)

Edit 2: Setting dune-cache: false when running on macOS resolves the problem. If dune-cache: true on macOS, then the problem still exists.