feat: use range when adding requirement

[baszalmstra]

Implements the behavior described in #285 .

When running pixi add python we would previously look at all platforms, add the requirement, and solve the environment. We would then take the lowest version between all platforms and pin that. So currently for python that would result in the requirement:

python = "3.12.0.*"

This is a very strict requirement. And would also fail to resolve if this version (or a higher version) is not available for all platforms (see #526 ).

This PR changes the behavior by instead adding a range requirement that allows change in the last segment of the version. And allowing for multiple versions if a version is not available for all platforms.

For python this would become:

python = ">=3.12.0,<3.13"

For the issue described in #526, this becomes:

ros-humble-rosbridge-server = ">=1.2.0,<1.4"

Note that 1.4 is selected instead of 1.3. This is because 1.2 is not available for all platforms.

Fix #526
Fix #285

[ruben-arts]

While testing this i got this situation. Not sure if this has anything to do with this pr yet. Just putting it here.

I get this error:

❯ pixi add python --build -p linux-64
  × Cannot solve the request because of: The following packages are incompatible
  │ |-- ros-humble-rosbridge-server >=1.2.0,<1.4 can be installed with any of the following options:
  │     |-- ros-humble-rosbridge-server 1.2.0 | 1.2.0 would require
  │         |-- python_abi 3.9.*, which can be installed with any of the following options:
  │             |-- python_abi 3.9
  │             |-- python_abi 3.9
  │ |-- python >=3.12.0,<3.13 cannot be installed because there are no viable options:
  │     |-- python 3.12.0 would constrain
  │         |-- python_abi 3.12.* *_cp312 , which conflicts with any installable versions previously reported
  │ 

On this initial pixi.toml file:

[project]
name = "range"
channels = ["conda-forge", "robostack-humble"]
platforms = ["linux-64", "osx-arm64", "osx-64"]

[tasks]

[dependencies]
ros-humble-rosbridge-server = ">=1.2.0,<1.4"
python = ">=3.9.15,<3.10"

It does add the following part to the pixi.toml but then fails the solve. Which is a known issue.

[target.linux-64.build-dependencies]
python = ">=3.12.0,<3.13"

But the version seems weird as that will not match with the ros-humble requirement

[ruben-arts]

Found it, this has nothing to do with this PR. But sits in the way we deal with the --build and --host in the fn add_specs_to_project:

let current_specs = match spec_type {
            SpecType::Host => project.host_dependencies(platform)?,
            SpecType::Build => project.build_dependencies(platform)?,
            SpecType::Run => project.dependencies(platform)?,
        };

This should not be done as we are solving them together. Will make a different PR to fix this.

[ruben-arts]

Awesome, works for me!