Don't panic from WorkspaceDefaultMembers?

[sourcefrog]

Hi, https://docs.rs/cargo_metadata/0.18.1/cargo_metadata/struct.WorkspaceDefaultMembers.html documents that it will panic on cargo <1.70, and it does.

For cargo-mutants, I'd like to use this but also support older versions of cargo, so it would be really nice if this was a runtime error rather than a panic. Or at least, if there was a documented version field that I could check before looking at it. Possibly I am missing some subtlety about why that's not feasible.

Thanks for a really helpful crate.

[jplatte]

As a workaround, you can use std::panic::catch_unwind to resume operation in case of a panic (unless you're compiling without unwinding).

[oli-obk]

You can use the https://crates.io/crates/rustc_version crate to check whether your rust is new enough for this field

[sourcefrog]

Also, just to confirm, this hinges on the version of cargo that's being invoked as cargo metadata, not on the version used to build the program, right?

[oli-obk]

yes

[clechasseur]

I ran into this issue also. Would it be acceptable to add a method to the WorkspaceDefaultMembers type to be able to check if it's available or not? If so, I can volunteer to work on a PR for this.

[Shnatsel]

I'm also interested in this for cargo auditable and I'm happy to contribute a PR.