Support PEP-735 "dependency-groups" in pyproject.toml

[itcarroll]

Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

PEP 735 is a long-awaited upgrade to the pyproject.toml file specification that adds a table for groups of dependencies. These "dependency-groups" are distinct from "optional-dependencies". In the same way that conda-lock supports optional dependencies with the --extras flag, it would make sense to follow uv and support dependency groups with a --group flag.

Why is this needed?

The pyproject.toml file can now include a table for dependencies that conda-lock does not recognize.

What should happen?

When a dependency-group table exists in a pyproject.toml file, then conda-lock should include the listed dependencies when called to lock, render, and install while allowing for customization. I believe replicating the behavior of --extras will work with a new flag for --group. By default, locking would solve for all dependencies (including all extras and groups) and installing includes only requested dependencies (asked for with --extras and --group). I'm not entirely sure about render...

Additional Context

No response

[maresb]

Thanks a lot @itcarroll for pointing this out!

It seems to me like it would make sense to map dependency groups to categories. I'd be happy to review a PR that attempts this.

[itcarroll]

How would you like to handle name collisions with categories from an environment.yml?

[maresb]

Good question! I think it probably makes most sense to merge them. Can you think of any other plausible options?

Thanks so much for working on this!!! 🙏