git extended version for leiningen

project.clj

(use '[clojure.java.shell :only [sh]])

(def version "0.1.1")

(defn clean? []
  (empty? (:out (sh "git" "diff-index" "HEAD"))))

(defn tagged? [version]
  (let [tag (.trim (:out (sh "git" "describe" "--tags" "--exact-match") ""))]
    (= tag version)))

(defn get-branch []
  "Returns branch name if not master"
  (let [ref (:out (sh "git" "symbolic-ref" "HEAD") "")
        [[_ branch]] (re-seq #"refs/heads/(.*)" ref)
        ;; if detatched head on ci server check environment variable
        branch (if branch branch (System/getenv "BRANCH")) ]
    (if-not (= branch "master") branch)))

(defn get-hash []
  (.substring (:out (sh "git" "rev-parse" "HEAD")) 0 6))

;; if version is tagged and working copy is clean use unmodified version
;; otherwise append branch (when not master)
;; and hash if clean, or -"SNAPSHOT" when dirty
(def version+
  (let [clean (clean?)]
    (if (and clean (tagged? version)) version
        (str version
             (if-let [branch (get-branch)] (str "-" branch))
             "-" (if clean (get-hash) "SNAPSHOT")))))

(defproject cherry-pitter version+
...