uv build fails to include modules that have symlinks elsewhere in project

[tcjennings]

Summary

As best as I can tell, uv build refuses to add modules to a wheel file when those modules have symlinks elsewhere in the project. These symlinks are not otherwise involved in the package tree. hatch build still works correctly.

Minimal Reproducible Example

• uv 0.5.23

uv init --package youvee-test
cd youvee-test
mkdir -p src/youvee_test/foo/templates
mkdir -p src/youvee_test/foo/settings

touch src/youvee_test/__init__.py
touch src/youvee_test/foo/__init__.py
touch src/youvee_test/foo/settings/__init__.py
touch src/youvee_test/foo/templates/__init__.py
touch src/youvee_test/foo/templates/module.py
touch src/youvee_test/foo/templates/not_py.yaml

pyproject.toml

[project]
name = "youvee-test"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
authors = [
    { name = "...", email = "..." }
]
requires-python = ">=3.12"
dependencies = []

[project.scripts]
youvee-test = "youvee_test:main"

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

uv build creates a correct wheel at this point:

❯ unzip -l dist/youvee_test-0.1.0-py3-none-any.whl
Archive:  dist/youvee_test-0.1.0-py3-none-any.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
       57  02-02-2020 00:00   youvee_test/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/settings/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/templates/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/templates/module.py
        0  02-02-2020 00:00   youvee_test/foo/templates/not_py.yaml
      166  02-02-2020 00:00   youvee_test-0.1.0.dist-info/METADATA
       87  02-02-2020 00:00   youvee_test-0.1.0.dist-info/WHEEL
       49  02-02-2020 00:00   youvee_test-0.1.0.dist-info/entry_points.txt
      834  02-02-2020 00:00   youvee_test-0.1.0.dist-info/RECORD
---------                     -------
     1193                     10 files

Add a symlink farm to the project root.

mkdir ./foo
pushd foo
ln -s ../src/youvee_test/foo/settings .
ln -s ../src/youvee_test/foo/templates .
popd

uv build creates an incorrect wheel now:

❯ unzip -l dist/youvee_test-0.1.0-py3-none-any.whl
Archive:  dist/youvee_test-0.1.0-py3-none-any.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
       57  02-02-2020 00:00   youvee_test/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/__init__.py
      166  02-02-2020 00:00   youvee_test-0.1.0.dist-info/METADATA
       87  02-02-2020 00:00   youvee_test-0.1.0.dist-info/WHEEL
       49  02-02-2020 00:00   youvee_test-0.1.0.dist-info/entry_points.txt
      475  02-02-2020 00:00   youvee_test-0.1.0.dist-info/RECORD
---------                     -------
      834                     6 files

hatch build creates a correct wheel:

❯ unzip -l dist/youvee_test-0.1.0-py3-none-any.whl
Archive:  dist/youvee_test-0.1.0-py3-none-any.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
       57  02-02-2020 00:00   youvee_test/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/settings/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/templates/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/templates/module.py
        0  02-02-2020 00:00   youvee_test/foo/templates/not_py.yaml
      166  02-02-2020 00:00   youvee_test-0.1.0.dist-info/METADATA
       87  02-02-2020 00:00   youvee_test-0.1.0.dist-info/WHEEL
       49  02-02-2020 00:00   youvee_test-0.1.0.dist-info/entry_points.txt
      836  02-02-2020 00:00   youvee_test-0.1.0.dist-info/RECORD
---------                     -------
     1195                     10 files

Remove a symlink from the farm

rm foo/settings

uv build is partially correct: the module that is not symlinked into the farm is now included:

❯ unzip -l dist/youvee_test-0.1.0-py3-none-any.whl
Archive:  dist/youvee_test-0.1.0-py3-none-any.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
       57  02-02-2020 00:00   youvee_test/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/__init__.py
        0  02-02-2020 00:00   youvee_test/foo/settings/__init__.py
      166  02-02-2020 00:00   youvee_test-0.1.0.dist-info/METADATA
       87  02-02-2020 00:00   youvee_test-0.1.0.dist-info/WHEEL
       49  02-02-2020 00:00   youvee_test-0.1.0.dist-info/entry_points.txt
      565  02-02-2020 00:00   youvee_test-0.1.0.dist-info/RECORD
---------                     -------
      924                     7 files

Platform

Darwin 24.1.0 arm64

Version

uv 0.5.23 (ba42467 2025-01-23)

Python version

Python 3.13.0, Python 3.12.7

[charliermarsh]

Does python -m build (using https://github.com/pypa/build) produce the same result?

[tcjennings]

For what it's worth, python -m build (without involving uv at all) has the same behavior.

rm -rf .venv
python -m venv .venv
activate .venv/bin/activate
pip install build
python -m build

[zanieb]

If python -m build has the same behavior as uv build then this is a Hatch-specific problem, I think.

[tcjennings]

I think I found the incantation that works around whatever the problem is: explicitly exclude and skip the symlink farm directory.

pyproject.toml:

[tool.hatch.build]
skip-excluded-dirs = true
exclude = ["/foo"]