failed when `mypy` exists on path

[FelisNivalis]

I'm using pylsp-mypy with coc.nvim and have pyenv installed. When linting, pylsp-mypy detects mypy is on path and tries to execute it, but it's only installed on one of my pyenv venvs, so it fails with

pyenv: mypy: command not found

The `mypy` command exists in these Python versions:
...

[Richardk2n]

When mypy exists on path it is used. This is to assure that common venv use cases work. Therefore, this is intended behavior. mypy should not exist on PATH if you do not intent to use it.

[FelisNivalis]

I understand that. The issue here is that pyenv works in a way that all executables in ALL environments are put in a shims folder so only checking whether mypy is on PATH does not ensure mypy exists in the current virtual env.

I think it would be better either to check mypy exists on the corresponding bin path of VIRTUAL_ENV, or make extra checks for pyenv.

[Richardk2n]

This kind of sounds like pyenv purposely puts broken executables at the front of PATH. I would not encourage changing the checking for venvs as it already is pretty confusing and writing code dependent on venv directory structure might break things (and it might not be applicable to the system-wide installation).

In terms of extra check for pyenv, that might be ok, but I am not too keen on doing it. If you can write a PR that does this without too much clutter I am willing to merge it.

An easy workaround for you would be installing mypy in your active venv.