Staging an installation of a project that uses project-mode=false

[rossburton]

I have a project that uses poetry to build some python tools. It sets package-mode = false and then defines some tools like:

[tool.poetry.dependencies]
foobar = {path = "tools/foobar, develop = true}

The pattern here is that the project does poetry install and the tools are then available in a venv.

However for reasons I'm trying to build a distribution package of the tools, so I don't want poetry to install into a venv but instead into a staging prefix of my choosing.

For example, if I was using pypa/build and pypa/installer I'd just python3 -minstaller foo.whl --destdir=/my/staging/dir and I'd have /my/staging/dir/usr/lib/python3.14/site-packages/... populated.

However I can't build a wheel when poetry is not in package mode, and poetry install doesn't have a dest/root dir mode. Is there a solution to this that I can't see?

[delcenjo]

With package-mode = false the root project is intentionally not a package, so Poetry won't build a wheel for it and poetry install only targets the project's virtualenv — there is no --root / --destdir equivalent. For a staged install into a prefix you have two clean paths.

1. Export the locked dependencies and let pip do the staged install

pip supports prefix / root / target installs, which Poetry does not:

# resolve + pin everything Poetry manages
poetry export --without-hashes -f requirements.txt -o requirements.txt

# stage into your prefix (pip understands --prefix / --root / --target)
python -m pip install --prefix /my/staging/dir -r requirements.txt

(poetry export is provided by the poetry-plugin-export plugin on Poetry 2.x.)

That populates /my/staging/dir/lib/python3.x/site-packages/..., the same result as your installer --destdir example.

2. Build and stage your own path tools as wheels

Your tools/foobar entries are packages (path dependencies), so build each one and install it into the prefix with the installer:

python -m build tools/foobar       # produces tools/foobar/dist/foobar-*.whl
python -m installer --destdir /my/staging/dir tools/foobar/dist/foobar-*.whl

So: keep Poetry for dependency resolution, but do the staged install with pip (--prefix / --root) for the dependency set, and build + installer for your own path packages. The non-package root project itself has nothing to install beyond pulling those in.