Looks good to me, thanks!

I don't think that rust/cargo ensures that the crate actually compiles with the specified rust-version. For example, try using a method such as https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.extract_if which was stabilized in 1.88. No errors or warnings happen for me.

So it's probably good to keep the rust-toolchain.toml in place, in addition to specifying the rust-version.

I don't think that rust/cargo ensures that the crate actually compiles with the specified rust-version. For example, try using a method such as https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.extract_if which was stabilized in 1.88. No errors or warnings happen for me.

So it's probably good to keep the rust-toolchain.toml in place, in addition to specifying the rust-version.

Or can we use github ci to make sure the minimum version of rust can be compiled normally?

I'm also fine with that. What do you think, @haixuanTao ?

I didn't know that this did not work as expected.

what does it do then?

I was under the impression that it could be neat to be able to switch between rust version between nodes.

I found a discussion about this:
dani-garcia/vaultwarden#3907

According to the official document (https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file):

Some projects find themselves ‘pinned’ to a specific release of Rust and want this information reflected in their source repository. This is most often the case for nightly-only software that pins to a revision from the release archives.

I tend to remove rust-toolchain.toml, and then we can change the test version in github actions to the minimum version supported by dora. Under normal circumstances, if the minimum version passes the test, all rust versions higher than this version should pass.

I also looked at the official rust project,
https://github.com/rust-lang/cargo It does not add rust-toolchain.toml, and sets the minimum supported version through rust-version.
https://github.com/rust-lang/crates.io/ It adds rust-toolchain.toml without setting rust-version in Cargo.toml.

Sounds good to me! We can reuse cargo's msvr CI job: https://github.com/rust-lang/cargo/blob/6833aa715d724437dc1247d0166afe314ab6854e/.github/workflows/main.yml#L291

It uses https://github.com/taiki-e/cargo-hack?tab=readme-ov-file#--rust-version . Something like this might also work for us.

I opened #1094 to add a msvr CI job