Reporting unused third-party dependencies

[guillaumecherel]

Hi,

First, thanks for the work on this tool ! I’ve been using the polylith architecture for a while and only recently started integrating your polylith python tool.

I’d like to check automatically that dependencies declared in the projects pyproject.toml, including bricks and third-party, are actually used in the code. The poly check command reports unused bricks, but not third-party dependencies if I’m correct. Is this by design?

[DavidVujic]

Hi @guillaumecherel, good to hear that you use the polylith architecture! The poly check command should report on missing third-party dependencies too. The check should be pretty accurate about third-party dependencies if you have a lock-file in the project directory or a shared one (such as when using uv workspaces).

If there isn't any lock file, then the tooling will try its best by inspecting the current virtual environment and might miss out on a missing dependency if it is registered in an other project also. But in general, it should find out the missing bricks and third-party libraries.

How does your setup look like? (uv, poetry ... lock-files etc.)

[guillaumecherel]

Hi @DavidVujic, thanks for your answer.

That’s right, poly check does report on missing third-party dependencies, but I meant unused dependencies. I use uv workspaces and reorganized my project following your https://github.com/DavidVujic/python-polylith-example-uv. For example in your uv workspace example, I would expect that after adding a dependency on tqdm to the project my_fastapi_project, poly check would fail, since none of the project’s bricks import tqdm. For example, I one of the last 4 commands below would fail:

git clone git@github.com:DavidVujic/python-polylith-example-uv.git
cd python-polylith-example-uv/
cd projects/my_fastapi_project/
uv add tqdm
cd ../..
uv run poly check
uv run poly check --strict
uv run poly check --directory projects/my_fastapi_project/
uv run poly check --strict --directory projects/my_fastapi_project/

[DavidVujic]

Aha, sorry I misunderstood you. Currently, the poly check command will report on unused bricks but doesn't report on unused third-party dependencies. I had a quick look if uv support this, but they seem to refer to other tools like fawltydeps and such.

To get a visual overview over what's being used you could run poly libs to see the usage of third-party libs, but it won't alert on any unused libraries.

The unused bricks feature is relatively new and described here: #361

[guillaumecherel]

Yes, I noticed I could identify unused deps with poly libs and I figured there was a way to automate the check. I’ll have a look at fawltydeps ! Thanks for the help.