While trying to implement uv in my current pipeline I came across an issue regarding dependencies.

To sketch a summary of my setup.

I'm running my pipeline in alpine, which brings some challenges. Some packages cannot be easily compiled (and don't have a wheel available), which is why I use the extra index https://github.com/alpine-wheels/index .

I use that index for packages like mysqlcient and reportlab.

My pipeline also wants to install cryptography==41.0.3, but because cryptography is available in the alpine-wheel index, it tries to install it from there. Though cryptography already has available wheels via pypi, so I don't want it to install via the alpine-wheels repo.

My thought was to first run uv once to only install cryptography, so I dont use the index. And after that I run uv with my normal dependencies via pyproject.toml. But it appears that uv doesn't see the already installed cryptography.

Because I run uv in a pipeline I use the --system flag.

See the output below:

/ # uv pip install --system cryptography==41.0.3
Resolved 3 packages in 114ms
Downloaded 3 packages in 114ms
Installed 3 packages in 6ms
 + cffi==1.16.0
 - cryptography==40.0.2
 + cryptography==41.0.3
 + pycparser==2.21
/ # uv pip install --system --extra-index-url https://alpine-wheels.github.io/index -r pyproject.toml
  x No solution found when resolving dependencies:
  `-> Because there is no version of cryptography==41.0.3 and <my-project> depends on cryptography==41.0.3, we can conclude that the requirements are unsatisfiable.