🐞 `Pytest.test` wrongly assumes `"/opt/venv/bin/python"` is present in the user-provided container

[danielgafni]

What is the issue?

The current installation may easily fail if the user-provided container does not satisfy the assumptions of this installation process.

More specifically, in order of severance:

1. It hardcodes --python to an arbitrary location ("--python", "/opt/venv/bin/python") which may not be available. I think you wanna set UV_SYSTEM_PYTHON=true instead.
2. it performs a uv sync which will uninstall extras and non-default groups; if you wanna do it at least pass --inexact.
3. Is there a reason it sets a cache buster?
4. I also find it weird that it installs a specific Python version by default

I think both steps may belong to the optional container setup path here, but a user-provided container should be considered prepared to just run uv pip install over the module-provided pytest_otel.

Even more, I'd make this step optional as well, because users may want to cache this part before copying their source code into the container to avoid rebuilding this error on every source code change.

Dagger version

dagger v0.21.0 (image://registry.dagger.io/engine:v0.21.0) darwin/arm64/v8

Steps to reproduce

No response

Log output

  │ ✘ withExec uv pip install --python /opt/venv/bin/python /opt/pytest_otel 0.1s ERROR
  │ ┃ error: No virtual environment or system Python installation found for path `/opt/venv/bin/python
  │ ┃ uv venv` to create an environment
  │ ! exit code: 2

[danielgafni]

I was able to use the source code of pytest_otel from this repo here: typesafe-ai/daggerverse#42

It works with the tweaks described above:

• I am setting UV_SYSTEM_PYTHON=true
• I am simply running uv pip install <pytest_otel>

Ideally I'd just do uv add --group ci pytest-otel-<?dagger> to install this dependency before copying my Python source code into the container. It would be great it was published!

[danielgafni]

cc @vito