flycheck-clojure

https://github.com/clojure-emacs/squiggly-clojure.git

git clone 'git://github.com/clojure-emacs/squiggly-clojure.git'


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squiggly-clojure

Flycheck checker for Clojure, using eastwood, core.typed and kibit via cider.

See this blog post for more.

Warning!

Please read the documentation for each linter. Some of them come with warnings.

Installation

The package is available on Melpa:

M-x package-install flycheck-clojure

Add to your .emacs:

~~~.el (eval-after-load ‘flycheck ’(flycheck-clojure-setup)) (add-hook 'after-init-hook #'global-flycheck-mode) ~~~

Installing flycheck-pos-tip as well is strongly recommended, so that linting and type errors don't clash with cider's eldoc information.

M-x package-install flycheck-pos-tip

And add this to your .emacs:

~~~.el (eval-after-load ‘flycheck ’(setq flycheck-display-errors-function #'flycheck-pos-tip-error-messages)) ~~~

Dependencies in Clojure:

The Clojure code used to invoke the various specific linters is in

~~~.clj [acyclic/squiggly-clojure “0.1.2-SNAPSHOT”] ~~~

You should probably add that to your profiles.clj as part of the :dependencies vector.

It pulls in

~~~.clj [org.clojure/core.typed “0.2.72”] [jonase/eastwood “0.2.1” :exclusions [org.clojure/clojure]] [jonase/kibit “0.0.8”] ~~~

Configuration

See the sample-project subdirectory for examples of the configuration methods described below.

From Emacs

Squiggly Clojure comprises three Flycheck checkers, clojure-cider-typed, clojure-cider-kibit and clojure-cider-eastwood. You may exclude one or more of these by including them in the flycheck-disabled-checkers list. This can be done via the Local Variables: block at the end of a .clj file, e.g.

~~~.clj ;; Local Variables: ;; flycheck-disabled-checkers: (clojure-cider-kibit) ;; End: ~~~

but the following two methods are preferable for such persistent settings.

In project.clj

Add or merge

~~~.clj :plugins [[lein-environ “1.0.0”]] ~~~

and set an :env option map that includes :squiggly , e.g.

~~~.clj {:env {:squiggly {:checkers [:eastwood] :eastwood-exclude-linters [:unlimited-use]}}} ~~~

Here, you specify included checkers, as :eastwood, :kibit or :typed. If you set :eastwood-exclude-linters, it will be passed directly to Eastwood as described in its documentation. This configuration will apply to all source files in the project unless overridden by…

Namespace metadata

E.g.

~~~.clj (ns sample-project.core {:squiggly {:checkers [:eastwood :typed] :eastwood-exclude-linters [:unlimited-use]}} (:require [clojure.core.typed]) (:use [clojure.stacktrace]) ;; warning suppressed by :eastwood-exclude-linters ) ~~~

Precedence

If set in the metadata, the value of :squiggly fully overrides anything set in the project.clj: no fancy merging is performed.

And note that, if a checker is in flycheck-disabled-checkers, it will never be invoked no matter what you set in Clojure code.

Debugging

Many things can go wrong.

• Neither eastwood nor kibit is usually run repeatedly and in the REPL, so we may trigger bugs that don't matter to other people.
• There may be circumstances under which the checkers return output in an unanticipated form, which will then be unparseable in emacs.
• I don't really know Emacs Lisp. Could be an issue.

If, due to one of these or other problems, flycheck does not receive the proper callbacks, it may be stuck in a state where it will never try to check again. To reset (modulo some memory leaks perhaps) try turning flycheck-mode off and then on.

If something mysterious is happening, you may find it helpful to look at the *nrepl-messages* buffer, where CIDER silently logs all traffic between EMACS and Clojure. Among other things, you'll find here the Clojure expressions that were evaluated to initiate the checking, so you can run these directly from the REPL yourself.

TODO:

• Deal better with catastrophic failure of a checker. Currently, we silently ignore exceptions.
• Performance optimizations: throttling and narrowing.