Unexpected error when using uv_build with namespace=true and no-editable install

[hmvp]

Summary

Our project uses the layout that needs

[tool.uv.build-backend]
namespace = true

When changing the build backend from setuptools to:

[build-system]
requires = ["uv_build>=0.7.19,<0.8.0"]
build-backend = "uv_build"

a normal uv sync works as expected. But uv sync --no-editable errors with:

$ uv sync --no-editable
Resolved 135 packages in 1ms
  × Failed to build `test_project @ file:////home/user/git/repo_folder`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `uv_build.build_wheel` failed (exit status: 1)

      [stderr]
      Error: Failed to walk source tree: ``

      Caused by:
          0: IO error for operation on /home/user/git/repo_folder/src/test_project: No such file or directory (os error 2)
          1: No such file or directory (os error 2)

      hint: This usually indicates a problem with the package or the build environment.

in our src dir we don't have a folder named test_project but a number of folders named after specific "components" like this:

src
    ├─ api
    |   ├── __init__.py
    |   └── ...
    ├─ common
    |   ├── __init__.py
    |   └── ...
    └── ...

Platform

Linux 6.15.3-200.fc42.x86_64 x86_64 GNU/Linux

Version

uv 0.7.13 (uv_build 0.7.19)

Python version

Python 3.13.5

[konstin]

For this layout, you currently need to set module-name = ""; the build backend currently mainly assumes a single root module.