Last time I mentioned
that I helped making it possible for Eglot to use
jdtls, the Python helper
script packaged with Eclipse JDT to start the language server with sane
defaults. The only problem I had during my work on this is that
Python 3.9 or later, why my Ubuntu 20.04 machine comes with the 3.8.10 version.
Since changing the default Python on Ubuntu can bring pain,1 I decided to
have Emacs work with Python 3.9 only for my Java projects.
First, I installed the required Python packages:
$ sudo apt install python3.9 python3-9-venv
Then, in my Java project root directory I ran:
$ python3.9 -m venv env
Finally, I had to tell Emacs how to interact with this new Python environment.
In the root directory of my project I added a
.dir-locals.el file with the
((nil . ((buffer-env-command . ">&2 . \"$0\" && env -0") (buffer-env-script-name . "env/bin/activate") (python-shell-virtualenv-root . "./env"))))
I am using Augusto Stoffel’s buffer-env
to pick up the
activate script and run it automatically for me. Checking the
Python version with M-! /usr/bin/env python3 -V RET told me I was
doing the right thing. Keep in mind that you don’t have to set
buffer-env-command like I do. Here I am setting it back to its default value
because I changed it in my
init.el to specifically deal with
with everything in place Eglot correctly interfaced with
jdtls for a smooth
Java developing experience.
A note to myself: I will probably need to revisit this setup as soon as I move to the new Ubuntu LTS which, I guess, will provide a more recent Python by default.
Trust me on this. ↩