poetry: Poetry 1.1.x breaks mypy in a project with source dependencies

I am on the latest Poetry version.
I have searched the issues of this repo and believe that this is not a duplicate.
If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

OS version and name: MacOS 10.16.5
Poetry version: 1.1.1
Link of a Gist with the contents of your pyproject.toml file: link

Issue

This is an issue with mypy under .venv created with latest Poetry (v1.1.x) which works just fine if the .venv was created with older version (v1.0.10 or before)

Our project has two source dependencies on other internal projects. After the upgrade (and re-creating the .venv) running poetry run mypy . produces a whole bunch of errors like:

error: Cannot find implementation or library stub for module named 'our_source_project1.something'
error: Cannot find implementation or library stub for module named 'our_source_project2.something_else'

Digging through the logs, diffs and then mypy source code I narrowed it down to this:

Under Poetry v1.0 a .venv/lib/python3.8/site-packages/easy-install.pth file gets created which contains paths to each of our code dependency projects.

Under Poetry v1.1 this file doesn’t get created.

Thing is, mypy reads this specific file to find these source dependencies. (source). Without it it doesn’t know how to find them, hence the errors, and a broken build.

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 5
Comments: 21 (10 by maintainers)

Commits related to this issue

cryptol-remote-api: Upgrade to mypy-0.812 This upgrades `mypy` to version `0.812`. This is primarily motivated by a need to work around python-poetry/poetry#3094, which currently happens if you try t... — committed to GaloisInc/cryptol by RyanGlScott 3 years ago
cryptol-remote-api: Upgrade to mypy-0.812 This upgrades `mypy` to version `0.812`. This is primarily motivated by a need to work around python-poetry/poetry#3094, which currently happens if you try t... — committed to GaloisInc/cryptol by RyanGlScott 3 years ago

Most upvoted comments

I just found this issue today when I started running into the problem. Looks like MyPy v.0.800 was released today, 22 Jan 2021. I’m getting this error with the new 0.800 version.

andrewtemme on Jan 22, 2021

Fair call @abn . Now 🤞 mypy 0.800 gets released soon so I can upgrade :partyparrot:

kkozmic on Oct 13, 2020

The next release of mypy (0.800) will include a fix for this, but I’m not sure when it will come out since 0.790 was just released today

bryanforbes on Oct 9, 2020

Right, so you’re basically saying it’s more of a mypy bug than Poetry (which is fair enough).

Yes. However, if there is anything we can do to keep things compatible, I am happy to look into it. We can, at least for 1.1 play nice and write to easy-install.pth as well if there are no undesired side-effects.

I’d have to put something together from scratch as obviously I can’t use our production code. I’ll look into it over the coming weekend

Awesome. That would make things easier to triage/decide.

abn on Oct 6, 2020

works fine with latest poetry / mypy - dunno which is fixed but this seems good now

dimbleby on Jul 31, 2022

To be completely honest, it seems like too much effort for a temporary workaround. I’ll think on it.

If there are other cases that are important relying on the file, it might be a different story. Right now, I just haven’t found any.

abn on Oct 12, 2020

So I got carried away and created a reproduction @abn

git clone git@github.com:bug-repros/poetry-main.git
cd poetry-main
poetry install
make

This works under Poetry 1.0.10 and fails under 1.1.1 with the error from OP.

kkozmic on Oct 6, 2020