Support uv/pip's editable_mode configuration

[mdekstrand]

Problem description

Right now, Pixi uses uv's default settings for installing editable dependencies.

However, these defaults cause problems with packages being discovered by Pylance when editing in VS Code. The solution appears to be to install in either strict or compat mode (https://github.com/microsoft/pylance-release/blob/main/TROUBLESHOOTING.md#editable-install-modules-not-found). uv exposes a way to set this through its config-settings (https://docs.astral.sh/uv/reference/settings/#pip_config-settings), but I cannot find a way to set this setting for Pixi's usage of uv.

I might be migrating own packages to a different build backend in part to work around this problem, but it would probably help folks using setuptools to make editable installs statically-discoverable.

[claudius-kienle]

I would support this, as Pylance does not work with standard editable installs except installed with

pip install -e your-package --config-settings editable_mode=compat

I tried to add the editable_mode argument to the PyPiRequirement. However, I am not sure what is missing so I can pass it in the pixi.toml.

My changes can be found at https://github.com/claudius-kienle/pixi/tree/feat-config-settings

[tdejager]

Good idea! Thanks for the issue.