Support `UV_ONLY_BINARY` and `UV_NO_BINARY` environment variables

[njzjz]

This is useful with cibuildwheel or some other complicated tools in the CI environment.

pip has similiar PIP_NO_BINARY and PIP_ONLY_BINARY: https://pip.pypa.io/en/latest/cli/pip_install/#cmdoption-no-binary

[zanieb]

I think we've avoided this because we're not interested in supporting the pip syntax outside of the pip interface. Maybe we could namespace them e.g. UV_PIP_NO_BINARY in the meantime?

[henryiii]

Some of them are available, though, like UV_CONSTRAINT, UV_INDEX_URL, UV_EXTRA_INDEX_URL, and UV_BREAK_SYSTEM_PACKAGES. I don't really care what it's called, but it would be nice to have, as you can't pass flags through inside cibuildwheel to every command.

[sanmai-NL]

@zanieb Please consider that other package managers also support this, since it's a genuinely useful feature for containerized builds, and not just a Pip feature.

• PDM
• Poetry (no env var, but functionally somewhat equivalent persistent config).

[zanieb]

@sanmai-NL we do support this via persistent configuration, e.g.,

• https://docs.astral.sh/uv/reference/settings/#no-binary
• https://docs.astral.sh/uv/reference/settings/#no-binary-package
• https://docs.astral.sh/uv/reference/settings/#no-build
• https://docs.astral.sh/uv/reference/settings/#no-build-package

Since our top-level settings differ from pip (we don't use :all:, we have a dedicated flag instead), I'm not sure how best to introduce environment variables for this.

I guess:

UV_NO_BINARY=1
UV_NO_BINARY_PACKAGE="foo bar"

And uv pip users would need to use the new syntax too?