Sort dependencies in project.clj

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Context

Our lein-template adds ;; Please keep the dependencies sorted a-z. before the :dependencies-key in project.clj.

There's benefits for sorting this list (friction-free merges, improves readability, ..)

Task

We need a formatter to sort the dependency list

Acceptance criteria

dependency sorting:

(defproject corpus "unreleased"
  :dependencies [[c]
                 [a]])

should be formatted to

(defproject corpus "unreleased"
  :dependencies [[a]
                 [c]])

:exclusion sorting

(defproject corpus "unreleased"
  :dependencies [[a
                  :exclusions [c b]])

should be formatted to

(defproject corpus "unreleased"
  :dependencies [[a
                  :exclusions [b 
                               c]])

note the formatted newlines

Additional resources

inspiration for replacement of the :dependencies can be found here:

formatting-stack/src/formatting_stack/util/ns.clj

Line 59 in 2b7f0e5

(speced/defn replace-ns-form!

sorting might be something like:

(let [deps '[[c] 
             [a :exclusions [c b]]]]
  (->> deps
       (mapv (fn [clause]
               (let [exclusion-index (.indexOf clause :exclusions)]
                 (if (> 0 exclusion-index)
                   clause
                   (update clause (inc exclusion-index) (comp vec sort))))))
       (sort-by first)
       (vec)))
=> [[a :exclusions [b c]] [c]]

[vemv]

formatting-stack/src/formatting_stack/util/ns.clj

Line 59 in 2b7f0e5

(speced/defn replace-ns-form!

...is quite reliable in part because ns forms are a quite limited "DSL" without a lot of room for variations, significant whitespace, metadata, comments, quoting/unquoting etc

For most other Clojure code I wouldn't be too trigger-happy with code rewriting, as we currently don't directly use rewrite-clj, so it's not a technique we master.

Eventually we might have some rewrite-clj helpers/abstraction, allowing us to implement small formatters easily and reliably.

---

If I polished my old https://github.com/reducecombine/autonewline, some of that code might serve as the mentioned abstraction. Also worth studying cljfmt of course

Also important to find the right rewrite-clj version - there's rewrite-clj, rewrite-cljs, and clj-kondo's vendored rewrite-clj which might be interesting

[vemv]

https://github.com/kkinnear/zprint/blob/1.2.3/doc/reference.md#sort-dependencies does this

(I'll add optional zprint support soonish)