ci: add test for msrv

[jasonish]

The current MSRV is too new for our project, but thought I'd add a test for the
current MSRV.

In Cargo.toml, set rust-version to the current MSRV of 1.70.

Add a ci test to make sure the build and tests pass with the MSRV.

[Ethiraric]

I do plan on lowering MSRV. I do keep in mind this PR for the CI file. Wouldn't it be easier to use cargo-msrv?

[davvid]

As a point of reference, Alma/Rocky/RHEL 9.2 currently ship with rust/cargo 1.66.1. I'm always a fan of casting a wide compatibility net if it doesn't impede development too much.

[jasonish]

I do plan on lowering MSRV. I do keep in mind this PR for the CI file. Wouldn't it be easier to use cargo-msrv?

IMO, not really. This is a single awk expression to get the MSRV version of Rust right from the start. To use cargo-msrv you first have to install a Rust that meets its requirements, install cargo-msrv which takes about 10x longer to build than yaml-rust2, it will then go pull down the MSRV of Rust, and rebuild. Seems like a lot of overhead vs a single awk expression :)

Glad to hear you are lowering the MSRV. Our project tries to keep the MSRV inline with the major Linux distributions, right now Debian 12 is the hold-back with Rust 1.63.

[Ethiraric]

It will go down from 1.70 to 1.65 though. Going further down is possible but would be painful. 1.65 does only incur minimal changes to the code.

[jasonish]

It will go down from 1.70 to 1.65 though. Going further down is possible but would be painful. 1.65 does only incur minimal changes to the code.

[Edit: read your comment wrong :)]

Anyways, this is more just a comment on how we determine our MSRV. My usage of this crate will factor into our next major release which I hope to have a newer MSRV for anyways.

[Ethiraric]

While searching whether it was possible to have features change the MSRV, I found this: https://doc.rust-lang.org/cargo/guide/continuous-integration.html#verifying-rust-version

Do you have any idea how it fares in terms of CI times?

[jasonish]

While searching whether it was possible to have features change the MSRV, I found this: https://doc.rust-lang.org/cargo/guide/continuous-integration.html#verifying-rust-version

Do you have any idea how it fares in terms of CI times?

I have not tried cargo-hack, but with pre-compiled binaries, it should be faster than cargo-msrv. But IMO, why introduce more into your "supply chain" when a single awk expression will do :) Just my opinion though, my main concern is MSRV validation, not how it's done.

[Ethiraric]

Can this PR be rebased over master and the following changes be made:

• I'd like to ensure MSRV can go down to 1.65.0 with all features disabled. Would it be possible to have an extra key (even if it's commented) in Cargo.toml, like rust-version-no-features that would contain the 1.65.0? This is a temporary ugly hack.
• Can you run cargo check instead of compiling and running all tests? This also removes the git submodule update.

The defaults for yaml-rust2 are wrong on many levels and fixing them is a task for future me.

[jasonish]

Will look in the next few days.

[Ethiraric]

But IMO, why introduce more into your "supply chain" when a single awk expression will do :)

I do get your point. Reading back, I may have sounded like I disregarded your implementation, and I apologize. I mostly wanted to survey options and make the sanest choice.

[jasonish]

No worries. Just glad to see interest in commitment to a MSRV.