Error message when rust-version MAJOR is in the future (2, 2.0 or 2.0.0 or higher)

[peter-lyons-kehl]

Problem

Please, parse rust-version correctly. The current way (on both stable and nightly) is amusing:

❯ grep rust-version Cargo.toml 
rust-version = "2.92.0"

❯ cargo +nightly check --ignore-rust-version
error: failed to parse manifest at `/share/pkehl/GIT/ndd/Cargo.toml`

Caused by:
  rust-version 2.92.0 is older than first version (1.85.0) required by the specified edition (2024)

Applicable to local (path-based) dependencies or GIT-based dependencies, but regardless, the current parsing is incorrect.

[weihanglo]

Thanks for the bug report.

The parsing logic seems correct to me:

cargo/crates/cargo-util-schemas/src/manifest/rust_version.rs

Lines 14 to 25 in a0d9889

	pub fn is_compatible_with(&self, rustc: &PartialVersion) -> bool {
	let msrv = self.0.to_caret_req();
	// Remove any pre-release identifiers for easier comparison
	let rustc = semver::Version {
	major: rustc.major,
	minor: rustc.minor.unwrap_or_default(),
	patch: rustc.patch.unwrap_or_default(),
	pre: Default::default(),
	build: Default::default(),
	};
	msrv.matches(&rustc)
	}

It looks like the error message may need a tweak:

cargo/src/cargo/util/toml/mod.rs

Lines 1312 to 1319 in a0d9889

	if !edition_msrv.is_compatible_with(pkg_msrv.as_partial()) {
	bail!(
	"rust-version {} is older than first version ({}) required by \
	the specified edition ({})",
	pkg_msrv,
	edition_msrv,
	edition,
	)

Perhaps changing "is older" to "is incompatible"?

@rustbot label +S-accepted +E-easy -S-triage +A-diagnostics

[peter-lyons-kehl]

Wow, thank you for such a fast turnaround. I'm updating the issue title respectively.