flycheck-clj-kondo

This package integrates clj-kondo with Emacs via flycheck.

Installation

Before installing the Emacs package, make sure the clj-kondo is on your path. For installation instructions, see https://github.com/borkdude/clj-kondo.

MELPA

Install from MELPA:

M-x package-install flycheck-clj-kondo

Then add the following to your init.el:

(require 'flycheck-clj-kondo)

use-package

Install via use-package:

;; First install the package:
(use-package flycheck-clj-kondo
  :ensure t)

;; then install the checker as soon as `clojure-mode' is loaded
(use-package clojure-mode
  :ensure t
  :config
  (require 'flycheck-clj-kondo))

el-get

Install via el-get:

(el-get-bundle flycheck-clj-kondo
  :url "https://raw.githubusercontent.com/borkdude/flycheck-clj-kondo/master/flycheck-clj-kondo.el"
  (require 'flycheck-clj-kondo))

Multiple linters

To set up multiple linters, e.g. in combination with flycheck-joker, add this after you required the linter packages:

(dolist (checker '(clj-kondo-clj clj-kondo-cljs clj-kondo-cljc clj-kondo-edn))
  (setq flycheck-checkers (cons checker (delq checker flycheck-checkers))))

This ensures that the clj-kondo checkers are the first ones in the flycheck-checkers list. This is needed to make the chain work. To create the chain, also add the following code:

(dolist (checkers '((clj-kondo-clj . clojure-joker)
                    (clj-kondo-cljs . clojurescript-joker)
                    (clj-kondo-cljc . clojure-joker)
                    (clj-kondo-edn . edn-joker)))
  (flycheck-add-next-checker (car checkers) (cons 'error (cdr checkers))))

Project Setup

To lint across namespaces in a project, clj-condo needs a directory to store cached data. Create a .clj-kondo directory and lint the entire classpath from the command line.

Testing

Make sure Eldev is installed and run eldev test for testing, eldev lint for linting.

Troubleshooting

clj-kondo is on my PATH but Flycheck still says it's disabled (M-x flycheck-verify-setup)

Check your PATH according to Emacs: M-x shell, then echo $PATH. If there are any differences between that PATH and the one you are able to run clj-kondo from (e.g., your PATH according to Terminal on macOS), add them by including them in your Emacs config. For example, if you needed to include /usr/local/bin, you could add to init.el:

(setenv "PATH" (concat (getenv "PATH") ":/usr/local/bin"))
(setq exec-path (append exec-path '("/usr/local/bin")))

Then, restart Emacs.