"*" is not equal to any()

[dtolnay]

I would expect the following program to print * * true. Instead it prints * * false.

extern crate semver;
use semver::VersionReq;

fn main() {
    let any = VersionReq::any();
    let star = VersionReq::parse("*").unwrap();
    println!("{} {} {}", any, star, any == star);
}

[KodrAus]

Looks like we might need to implement equality traits manually by calling matches instead of deriving them?

[connorkuehl]

I don't think there's anything wrong with the equality traits. It looks like VersionReq derives it all the way down.

I added:

println!("{:?}\n{:?}", any, star);

to @dtolnay's test program.

The output is interesting:

* * false
VersionReq { predicates: [] }
VersionReq { predicates: [Predicate { op: Wildcard(Major), major: 0, minor: None, patch: None, pre: [] }] }

Definitely not the same 😨, but it should be.

I've spent some time trying to debug this but rust-lldb is going to give me an actual heart palpation. I'm having a horrible time setting breakpoints. That's a rant for some place else, though.

I wonder if it could be something to do with the crate boundary between semver and semver_parser? From::from() for semver::VersionReq and semver_parser::VersionReq? That code looks fairly standard, though.

VersionReq::parse("*") should lead to a call to semver_parser::range::parse(input) which should return a VersionReq with an empty predicates vec (one that must be translated from a sever_parser::VersionReq into a semver::VersionReq. I'm inclined to believe we have a stowaway predicate somewhere around here. Unfortunately without my debugger actually being able to break on any of these I can't find exactly where that weird predicate is being inserted.

tl;dr -- VersionReq::parse("*") is producing an VersionReq with a phantom predicate; the "any" VersionReqs being considered here are not consistent with each other.

[agalakhov]

It's even worse: the star does not work as expected.

let req = VersionReq::parse("*").unwrap();
let vers = Version::parse("0.1.0-beta");
assert!(req.matches(&vers)); // ??? !!!

[udoprog]

Hey,

The original equality issue is addressed in #151, and is also partly the motivation for why #159 was introduced.

Edit: original bug report filed in #150 which mentions this problem.

[matklad]

So, as pointed out by @agalakhov , * and any are indeed different, and to me it looks like this might be intentional?

The * is used for, at least in Cargo, "give me the latest version of a crate", where "latest" does not include prereleases. any is used internally to mean "I really don't care about version requirements at all, and prereleases are fine with me".

[dtolnay]

This is fixed in 1.0.0. "Any" is no longer a thing, because there is no SemVer syntax that behaves that way. "Star" is a different thing and is exposed as https://docs.rs/semver/1.0.0-rc.1/semver/struct.VersionReq.html#associatedconstant.STAR. If someone needs the semantics of sometimes always matching everything, then they should use Option<VersionReq>, and .map_or(true, |req| req.matches(version)).