Transitive index pinning using uv build / add

[rivershah]

I'm using uv for package management with private, per-project, token-based indices hosted on gitlab. While I can pin direct dependencies to specific indexes in pyproject.toml, I need a way to ensure that all downstream consumers can also resolve pinned indices. Currently, one has to exhaustively list out transitive dependencies and pinned indices in downstream packages.

Could uv build be enhanced to retain pinned index information, so when a downstream consumer uses uv add, the pinned indices are correctly applied?

This is a departure from the python standard but could significantly enhance private index-based builds and installs, which need to rely on fully specified wheel paths or git tags.

Example Scenario:

1. package_a has the following pyproject.toml:

dependencies = ["some_private_package"]

[tool.uv.sources]
some_private_package = { index = "some_private_package_private_index" }

[[tool.uv.index]]
name = "some_private_package_private_index"
url = "https://<token>@gitlab.example.com/api/v4/projects/123/packages/pypi"

package_b adds package_a as a dependency:

uv add package_a

package_b must manually specify the index for some_private_package and its transitive dependencies. Automating this process would streamline dependency management. wheel metadata discards all the pinned index information.

Is this functionality supported in uv build, or are there plans to add it?