pixi definitions fail with `pypi-dependencies`

[crusaderky]

Bug report

Bug description:

Following #142469, I tried using the cpython pixi recipe to build another package from sources:

[workspace]
channels = ["conda-forge"]
platforms = ["linux-64", "osx-arm64"]
preview = ["pixi-build"]

[dependencies]
python = { git = "https://github.com/python/cpython", subdirectory = "Tools/pixi-packages/default" }

[pypi-dependencies]
packagehelloworld = "*"

The above fails with pixi 0.62:

Error: × failed to solve the pypi requirements of environment 'default' for platform 'linux-64'
╰─▶ No Python interpreter found in the dependencies
help: Try: pixi add python

CC @lucascolley

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

[lucascolley]

thanks, this will need a fix in Pixi around https://github.com/prefix-dev/pixi/blob/main/crates/pixi_core/src/lock_file/resolve/pypi.rs#L360-L365

[lucascolley]

fixed by prefix-dev/pixi#5159

[lucascolley]

will be out in next Pixi release, this issue can probably be closed.

In the meantime, you can pixi run install-as tixi on the pixi repo if you want to use it from source @crusaderky