Add specifiers for virtual packages to the project toml file.

[ruben-arts]

Allow users to define virtual packages in the project configuration.

[ruben-arts]

Im having a hard disscussion with myself on how we shoudl specify the virtual packages.
But from a user perspective it could be as simple as adding them to the dependencies right?

[dependencies]
pytorch = "1.0"
__glibc = "2.17"
__aarchspec = { version = "1", build_string = "arm64"}

[wolfv]

Hmm, well, the problem is that these virtual dependencies specify a lower boundary on the system. E.g. with __glibc==2.17 one would only be guaranteed to be able to use the environment with a Linux that has glibc >=2.17 installed.

For that reason I think they are different enough to have their own section.

We could also call the section [system-requirements] for example, and then say something like

[system-requirements.linux]
glibc = ">=2.17"

[system-requirements.osx-arm64]
macos = ">=12"

etc.

[baszalmstra]

I like @wolfv s approach!

[ruben-arts]

I like it too! will continue with that!

[baszalmstra]

Although for the “selector” (e.g. linux) we need a seperate system still. Ill create an issue tomorrow so we can discuss.

[ruben-arts]

Right now virtual packages in the solve are specified like:

pub virtual_packages: Vec<GenericVirtualPackage>

This expects a version, not a match spec. Should that be changed?

[baszalmstra]

No that is correct. It describes the availabe virtual packages available on the system. So its an explicit version not a matchspec. You can see it as the “installed” virtual packages.

When we specify this in our project file it describes the minimum available virtual packages that should be present on the system for the lock file to be valid.

Packages (and thus also dependencies) can also specify dependencies on virtual packages. These should go in the normal dependencies section. (just like you mentioned earlier) However there they are no different from any other dependency and therefor dont need special treatment.

[baszalmstra]

[system_requirements]
windows = true
unix = true
cuda = "12.2"
macos = "10.15"
libc = { family = "glibc", version = "2.12" }

[target.osx-arm64.system_requirements]
cuda = "12.1"

[target.'not(osx-arm64)'.system_requirements]
cuda = "12.3"

So depending on the key the value is specific..