Summary

Here's a minimal repro. pyproject.toml at the root of the workspace:

[tool.uv.workspace]
members = ["foo"]

[[tool.uv.sources.numpy]]
path = "/var/tmp/numpy-2.2.0-cp313-cp313-manylinux_2_17_x86_64.manylinux2014_x86_64.whl"

And foo/pyproject.toml:

[project]
name = "foo"
version = "0.1.0"
requires-python = ">=3.13"
dependencies = ["numpy"]

[[tool.uv.sources.numpy]]
path = "/var/tmp/numpy-2.2.0-cp313-cp313-manylinux_2_17_x86_64.manylinux2014_x86_64.whl"
marker = "sys_platform == 'foobarbaz'"

So what we have is both a workspace-level and a project-level source for numpy. However, the project-level source is disabled by a marker that will never be true. Here's what I see when I uv sync:

$ rm -r .venv && uv sync
Using CPython 3.13.2
Creating virtual environment at: .venv
Resolved 3 packages in 60ms
Installed 1 package in 11ms
 + numpy==2.2.0

Contrast that with what I see if I remove the project-level source:

$ rm -r .venv && uv sync
Using CPython 3.13.2
Creating virtual environment at: .venv
Resolved 2 packages in 0.65ms
Installed 1 package in 11ms
 + numpy==2.2.0 (from file:///var/tmp/numpy-2.2.0-cp313-cp313-manylinux_2_17_x86_64.manylinux2014_x86_64.whl)

In this case the workspace-level source is used. The bug(?) is that it should've been used in both cases. I think the cause is structure of the following if statement:

In that code, if there's a project-level source with a matching name, then any workspace-level source is ignored. But this happens before markers are checked.

Platform

linux

Version

uv 0.7.13 (62ed17b 2025-06-12)

Python version

No response