Allow :dev-dependencies without :dependencies.

src/leiningen/deps.clj

@@ -65,11 +65,14 @@
       (.addDependency deps-task (make-dependency dep)))
     deps-task))
 
+(defn use-dev-deps? [project skip-dev]
+  (and (not skip-dev) (seq (:dev-dependencies project))))
+
 (defn deps
   "Download and install all :dependencies listed in project.clj.
 With an argument it will skip development dependencies."
   ([project skip-dev deps-set]
-     (when (seq (project deps-set))
+     (when (or (seq (project deps-set)) (use-dev-deps? project skip-dev))
        (when-not (:disable-implicit-clean project)
          (delete-file-recursively (:library-path project) true))
        (let [deps-task (make-deps-task project deps-set)
@@ -80,7 +83,7 @@ With an argument it will skip development dependencies."
          (copy-dependencies (:jar-behavior project)
                             (:library-path project)
                             true fileset)
-         (when (and (not skip-dev) (seq (:dev-dependencies project)))
+         (when (use-dev-deps? project skip-dev)
            (deps (assoc project :library-path (str (:root project) "/lib/dev"))
                  true :dev-dependencies))
          fileset)))

test/test_deps.clj

@@ -14,3 +14,15 @@
                        (.listFiles (file (:root test-project) "lib"))))]
     (doseq [j ["jdom-1.0.jar" "tagsoup-1.2.jar" "rome-0.9.jar"]]
       (is (jars j)))))
+
+(def dev-deps-only-project
+  (read-project "test_projects/dev-deps-only/project.clj"))
+
+(deftest test-dev-deps-only
+  (delete-file-recursively (file (:root dev-deps-only-project) "lib") true)
+  (deps dev-deps-only-project)
+  (let [jars (set (map #(.getName %)
+                       (.listFiles (file (:root dev-deps-only-project) "lib" "dev"))))]
+    (doseq [j ["clojure-1.2.0.jar"]]
+      (is (jars j)))))
+

test_projects/dev-deps-only/.gitignore

@@ -0,0 +1,4 @@
+pom.xml
+*jar
+lib
+classes

test_projects/dev-deps-only/project.clj

@@ -0,0 +1,2 @@
+(defproject dev-deps-only "1.0.0-SNAPSHOT"
+  :dev-dependencies [[org.clojure/clojure "1.2.0"]])

test_projects/dev-deps-only/src/dev_deps_only/core.clj

@@ -0,0 +1 @@
+(ns dev-deps-only.core)