Additionally cache ~/.rustup folder

[alerque]

Doesn't the actions-rs/toolchain action end up installing a toolchain in ~/.rustup and not caching it? Shouldn't / couldn't that be cached by default here as well?

[Swatinem]

The toolchain action should definitely be run before the cache action, and also needs to set the selected toolchain as local override (the cache uses the rustc version hash as one of the keys). I should maybe document that better.

[alerque]

I'm sorry maybe I wasn't clear. I understand the ordering issue (and have my rust-cache action setup to run after my toolchain action), my question was about whether the Rust toolchain was even getting cached at all. The build cache and project specific stuff is being cached, but the toolchain itself doesn't seem to be. The ./.rustup folder where the toolchain action stores the actual Rust installation. Or should that be the job of the toolchain action?

[Swatinem]

Or should that be the job of the toolchain action?

I don’t think they do any caching at all, but ideally yes, the toolchain should be responsible to do that. Also, if you are using stable, and the running is halfway up-to-date, it will be a noop anyway.

Because of the ordering of the two actions, you just can’t restore any kind of rustup cache before the toolchain action runs. And without the toolchain, you don’t have a cache key to begin with.

I’m unsure what the expectation here would be?

[alerque]

Because of the ordering of the two actions, you just can’t restore any kind of rustup cache before the toolchain action runs.

You are correct, I'm following now. I hadn't thought through that end of the stick. I'll mention this on the toolchain repo instead.