Flag for `--system-site-packages` when initializing venv

[foges]

We need to initialize our virtual environment with --system-site-packages (for torch). I can't seem to find a way to do it with this setup-uv github action. Am I missing something? If not it would be great to add this.

[eifinger]

Hi. I need to rehaul the whole venv activation stuff because it is currently not covering all usecases and a bit tricky to get right. Can you please provide more information on your usecase? A full example of your current workaround would be quite helpful. I am imagining that you can initialize the venv manually in a way like #124 (comment)

[foges]

Hey @eifinger. Yes, I do a similar thing. The use-case is that many machine learning libraries (eg. torch, flash-attn, triton, etc..) need to be installed in system site packages (and are often part of pre-built Nvidia docker images).

The GHA looks like this:

      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: 3.11
      - name: Install PyTorch
        run: pip install torch
      - name: Install uv
        uses: astral-sh/setup-uv@v5
      - name: Set up uv venv and sync packages
        run: |
          uv venv --system-site-packages --python 3.11
          uv sync --all-packages

The top-level pyproject.toml then looks like this

[tool.uv]
package = false
override-dependencies = [
    "torch; sys_platform == 'never'",
    ...
]