uv/crates/uv-pep508
Charlie Marsh e4fc875afa
Allow conflicting extras in explicit index assignments (#9160)
## Summary

This PR enables something like the "final boss" of PyTorch setups --
explicit support for CPU vs. GPU-enabled variants via extras:

```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.13.0"
dependencies = []

[project.optional-dependencies]
cpu = [
    "torch==2.5.1+cpu",
]
gpu = [
    "torch==2.5.1",
]

[tool.uv.sources]
torch = [
    { index = "torch-cpu", extra = "cpu" },
    { index = "torch-gpu", extra = "gpu" },
]

[[tool.uv.index]]
name = "torch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true

[[tool.uv.index]]
name = "torch-gpu"
url = "https://download.pytorch.org/whl/cu124"
explicit = true

[tool.uv]
conflicts = [
    [
        { extra = "cpu" },
        { extra = "gpu" },
    ],
]
```

It builds atop the conflicting extras work to allow sources to be marked
as specific to a dedicated extra being enabled or disabled.

As part of this work, sources now have an `extra` field. If a source has
an `extra`, it means that the source is only applied to the requirement
when defined within that optional group. For example, `{ index =
"torch-cpu", extra = "cpu" }` above only applies to
`"torch==2.5.1+cpu"`.

The `extra` field does _not_ mean that the source is "enabled" when the
extra is activated. For example, this wouldn't work:

```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.13.0"
dependencies = ["torch"]

[tool.uv.sources]
torch = [
    { index = "torch-cpu", extra = "cpu" },
    { index = "torch-gpu", extra = "gpu" },
]

[[tool.uv.index]]
name = "torch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true

[[tool.uv.index]]
name = "torch-gpu"
url = "https://download.pytorch.org/whl/cu124"
explicit = true
```

In this case, the sources would effectively be ignored. Extras are
really confusing... but I think this is correct? We don't want enabling
or disabling extras to affect resolution information that's _outside_ of
the relevant optional group.
2024-11-19 01:06:25 +00:00
..
src Allow conflicting extras in explicit index assignments (#9160) 2024-11-19 01:06:25 +00:00
Cargo.toml Fix feature scoping for pep508 wasm32 support for ruff (#8694) 2024-10-30 12:21:23 +00:00
Changelog.md Add `uv-` prefix to all internal crates (#7853) 2024-10-01 20:15:32 -04:00
License-Apache Add `uv-` prefix to all internal crates (#7853) 2024-10-01 20:15:32 -04:00
License-BSD Add `uv-` prefix to all internal crates (#7853) 2024-10-01 20:15:32 -04:00
Readme.md Link to Dependency specifiers instead of PEP 508 (#8411) 2024-10-21 14:43:38 -04:00

Readme.md

Dependency specifiers (PEP 508) in Rust

Crates.io PyPI

A library for dependency specifiers, previously known as PEP 508.

Usage

use std::str::FromStr;
use pep508_rs::Requirement;

let marker = r#"requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8""#;
let dependency_specification = Requirement::from_str(marker).unwrap();
assert_eq!(dependency_specification.name, "requests");
assert_eq!(dependency_specification.extras, Some(vec!["security".to_string(), "tests".to_string()]));

Markers

Markers allow you to install dependencies only in specific environments (python version, operating system, architecture, etc.) or when a specific feature is activated. E.g. you can say importlib-metadata ; python_version < "3.8" or itsdangerous (>=1.1.0) ; extra == 'security'. Unfortunately, the marker grammar has some oversights (e.g. https://github.com/pypa/packaging.python.org/pull/1181) and the design of comparisons (PEP 440 comparisons with lexicographic fallback) leads to confusing outcomes. This implementation tries to carefully validate everything and emit warnings whenever bogus comparisons with unintended semantics are made.