python-ide.org 6.5 KB
Installation
LSP mode
First one needs to install the lsp-mode package for Emacs. If your Emacs packages are managed by GNU Guix, you can add emacs-lsp-mode to your manifest file (the manifest.scm file).
(specifications->manifest '(... "emacs-lsp-mode" ... ))
Company
Also consider installing emacs-company to show completions:
(specifications->manifest '(... "emacs-company" ... ))
Python language server
Emacs also needs a Python language server to run, with which it can communicate and from which it can get information about the code you write.
. /bin/activate python3 -m pip install python-language-server[all]
Configuration
UNCLEAR Flycheck
LSP mode will activate flycheck or flymake to help with checking your code.
(add-hook 'after-init-hook #'global-flycheck-mode) (setq-default flycheck-temp-prefix ".flycheck")
lsp-mode without use-package
Load the package
Make sure lsp-mode is installed and loaded:
(require 'lsp-mode)
LSP's own diagnostics
To disable the LSP diagnostics (and instead rely on flake8):
(setq lsp-diagnostics-provider :none)
Add lsp hook for Python
Start lsp when you open a file for each langauge. lsp-mode will start all the other minor modes necessary.
(add-hook 'python-mode-hook #'lsp)
Amount of documentation shown
Change the amount of documentation lsp-mode shows when your cursor rests on a function. Show all documentation.
(setq lsp-eldoc-render-all t)
Disable the pylint plugin of the language server
(We will use flake8, not pylint.)
(setq lsp-pylsp-plugins-pylint-enabled nil)
UNCLEAR Set flake8 as a checker
This step is still unclear, because it might not be needed, since the checker config is also done in the dir-locals.el file.
(setq flycheck-checker 'python-flake8)
Project site configuration
Set Emacs handling of local variables
(setq enable-local-variables t)
This will make Emacs:
Set the safe variables, and query (once) about any unsafe variables.
UNCLEAR dir-locals.el in root directory of project
(Still unclear if all settings are needed.)
Add a dir-locals.el in the root directory of your project and don't forget to add it to =.gitignore=:
((python-mode . ((fill-column . 80) (flycheck--automatically-disabled-checkers . '(python-pylint lsp python-pycompile)) (flycheck--automatically-enabled-checkers . '(python-flake8)) (lsp-clients-pylsp-library-directories . ("/lib/python3.10/site-packages")) (lsp-pylsp-plugins-jedi-completion-enabled . nil)
;; Somehow lsp-pylsp-plugins-flake8-config is ignored ;; or does not work. ;; (lsp-pylsp-plugins-flake8-config . "/.flake8")) ;; Using the general flycheck setting instead. (flycheck-flake8rc . "/home/hans/dev/stackfuel/.flake8")
(lsp-pylsp-plugins-flake8-enabled . t) (lsp-pylsp-plugins-flake8-max-line-length . 80) ;; The Python executable to use for running flake8. (flycheck-python-flake8-executable . "/bin/python3"))))
There might be an alternative to hardcoding the venv directory:
((python-mode . ((eval . (let ((filename (file-name-concat ;; ensures there is a slash at the end (file-name-as-directory (let ((d (dir-locals-find-file "."))) (if (stringp d) d (car d)))) "/bin/python3"))) (cons 'flycheck-python-flake8-executable filename))))))
But I could not get that to work yet.
There is also apparently some flag that needs to be set to allow evaluation of expressions in a dir-locals.el file. This also indicates, that this method might not be the safest.
Notes
- company will provide auto complete suggestions
- flycheck will highlight warnings and errors
- xref can find the definition of a function or variable
- eldoc will show function documentation in the minibuffer
Safe local variables
When opening a Python file which resides in a directory or subdirectory of a directory in which a =.dir-locals.el= file exists, Emacs will ask you about applying the settings within the =.dir-locals.el= file to your buffer. This can be avoided by marking the settings as safe:
(put 'lsp-pylsp-plugins-jedi-completion-enabled 'safe-local-variable (lambda (_) t)) (put 'lsp-pylsp-plugins-flake8-max-line-length 'safe-local-variable (lambda (_) t)) (put 'lsp-pylsp-plugins-flake8-enabled 'safe-local-variable (lambda (_) t)) (put 'lsp-pylsp-plugins-flake8-config 'safe-local-variable #'stringp) (put 'flycheck-add-next-checker 'safe-local-variable (lambda (_) t)) (put 'flycheck--automatically-enabled-checkers 'safe-local-variable (lambda (_) t)) (put 'flycheck--automatically-disabled-checkers 'safe-local-variable (lambda (_) t)) (put 'flycheck-checker 'safe-local-variable (lambda (_) t)) (put 'lsp-pylsp-plugins-flake8-ignore 'safe-local-variable (lambda (_) t))
Possibly using something like:
(add-to-list 'safe-local-variable-values '(lsp-pylsp-plugins-jedi-completion-enabled . nil))
is a better way to set which variables are safe.
Usage
Check configuration
The keyboard shortcut is: C-c ! v.
The procedure name is: flycheck-verify-setup.