schemas: using enumerated `ResolveVersion`

[secona]

Problem

For lockfile versions, the schemas currently use Option<u32>. The problem with this is that it may become ambiguous when the version is null. Unsure if we should use ResolveVersion directly or define our own.

cargo-plumbing/crates/cargo-plumbing-schemas/src/lock_dependencies.rs

Lines 15 to 18 in be943f3

	pub enum LockDependenciesOut {
	Lockfile {
	version: Option<u32>,
	},

In #69, I noticed that resolve_with_previous can output a resolve with version ResolveVersion::V2. However, since ResolveVersion serializes V2 into a None, this results in a null version in the output messages.

I also noticed that using read-lockfile to read old Cargo.lock versions outputs a null as the version. I think this is fine, but what do we think of actually detecting versions to prevent null in the output messages?

cargo-plumbing/tests/testsuite/read_lockfile.rs

Lines 554 to 628 in be943f3

	#[cargo_test]
	fn old_lockfile() {
	let cksum = Package::new("a", "0.1.0").publish();
	let p = project()
	.file("src/lib.rs", "")
	.file(
	"Cargo.toml",
	r#"
	[package]
	name = "foo"
	version = "0.0.1"
	edition = "2015"
	authors = []
	[dependencies]
	a = "0.1.0"
	"#,
	)
	.file(
	"Cargo.lock",
	&format!(
	r#"
	[root]
	name = "foo"
	version = "0.0.1"
	dependencies = [
	"bar 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
	]
	[[package]]
	name = "a"
	version = "0.1.0"
	source = "registry+https://github.com/rust-lang/crates.io-index"
	[metadata]
	"checksum a 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "{cksum}"
	"#,
	),
	)
	.build();
	p.cargo_plumbing("plumbing read-lockfile")
	.arg("--lockfile-path")
	.arg(p.root().join("Cargo.lock"))
	.with_status(0)
	.with_stdout_data(
	str![[r#"
	[
	{
	"reason": "lockfile",
	"version": null
	},
	{
	"reason": "locked-package",
	"id": "registry+https://github.com/rust-lang/crates.io-index#a@0.1.0"
	},
	{
	"reason": "locked-package",
	"id": "foo@0.0.1",
	"dependencies": [
	"registry+https://github.com/rust-lang/crates.io-index#bar@0.1.0"
	]
	},
	{
	"reason": "metadata",
	"checksum a 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)": "3436ae58a84bb2033accec0cb50c6611f312249899579714793e0d0509470cd9"
	}
	]
	"#]]
	.is_json()
	.against_jsonlines(),
	)
	.run();
	}

Tasks

• Change Option<u32> to u32 in output messages (fix: Remove Option from lockfile version out messages #98)
• Use enum instead of u32 for versions

[epage]

We shouldn't literally read the null and turn that into None but should have the same version inference logic as into_resolve

[secona]

To make this consistent with other operations in read-lockfile, we can utilize EncodableResolve::normalize() for the inference logic and store the inferred version in NormalizedResolve.