David Allsopp

Travis caching definitely has one over GHA caching with the automatic detection of changes (as you said in https://github.com/ocaml/setup-ocaml/issues/159#issuecomment-882409583) - the need to generate the cache key _before_ retrieving things...

It's _better_ to use `opam exec` (because it's explicit), but I agree that this would be a useful feature

`--enable-shell-hook` won't work for the Windows shells (yet) - it only works for bash, etc.

Another alternative would simply be to turn off the `opam-pin` feature for the workflow where you're testing the locking and do the full set-up as part of the job commands...

I don't know what version of Visual Studio msvc64c is compiled with in opam-repository-mingw, but if you use the msvc64 variant then it will rebuild OCaml from sources (slower, but...

@voodoos - you need to add the ocaml-beta-repository explicitly, then that should work

I don’t think it should be extended to recognise that version string - the input is it intended to be an opam package version, but access to betas could definitely...

@kit-ty-kate - you're right, it shouldn't be necessary to have to specify either the beta repository or the fact betas are wanted. Saying `4.13.x` gives everything that's needed: the fact...

Agreed. I think is just a case of taking the Action and Usage sections from v1 (see [pre-v2 merge](https://github.com/ocaml/setup-ocaml/tree/25608863085910e9c2683873047587fe0e92099a#set-up-ocaml) and updating them.

Note, just in passing, that [Haskell](https://github.com/actions/starter-workflows/blob/main/ci/haskell.yml) and [Erlang](https://github.com/actions/starter-workflows/blob/main/ci/erlang.yml) got their workflows in before new submissions were frozen last August.