Live linting with clj-kondo

clj-kondo is a linter that can be called from flycheck, providing live static code analysis on your Clojure code as you type. Simple open any Clojure file (.clj, .cljs, .cljc, .edn) and start typing.

clj-kondo does not need a running Clojure REPL to work.

When errors are detected by the lint tool, a mark appears in the margin showing the line. A wavy underscore shows where on the line the issue is. Moving the cursor to the underscore will show a pop-up describing the error.

The total number of errors and warnings are show in in the Space bar.

Navigating linting errors

SPC e L opens a window with a buffer containing the list of linting errors for the current file. Navigate between linting errors using j and k. RET to select an error, focusing the cursor in the other buffer on that error

SPC b x to close the buffer and window when you have finished.

Keeping the flycheck buffer open will update as you move to linting errors in the source code buffer.

Configure Spacemacs Clojure layer with clj-kondo

Requirements for using clj-kondo as a live linter:

1. syntax-checking layer is present in dotspacemacs-configuration-layers, which provides flycheck.
2. clj-kondo is available on PATH (see clj-kondo install instructions).
3. Spacemacs develop branch as of September 2019 or later

Add a variable called clojure-enable-linters to the clojure with the value 'clj-kondo.

    (clojure :variables
             clojure-enable-linters 'clj-kondo)

SPC q r to restart Spacemacs (or simply SPC f e R to reload the configuration)