Produce a warning when acting as plugin but no matching project depen…

…dency

Fixes #45

CHANGES.md

@@ -1,3 +1,10 @@
+## 0.1.28 - 15 Jul 2016 
+
+A warning is now produced when using pretty as a plugin, but it is not a 
+project dependency.
+
+[Closed Issues](https://github.com/AvisoNovate/pretty/issues?q=milestone%3A0.1.28+is%3Aclosed)
+
 ## 0.1.27 - 1 Jul 2016
 
 Qualified keys in exception maps are now printed properly.

project.clj

@@ -1,14 +1,16 @@
-(defproject io.aviso/pretty "0.1.27"
+(defproject io.aviso/pretty "0.1.28"
   :description "Clojure library to help print things, prettily"
   :url "https://github.com/AvisoNovate/pretty"
   :license {:name "Apache Sofware License 2.0"
             :url  "http://www.apache.org/licenses/LICENSE-2.0.html"}
   :dependencies [[org.clojure/clojure "1.5.0"]
                  [org.clojure/tools.logging "0.3.1" :optional true]]
   :plugins [[lein-codox "0.9.3"]]
-  :profiles {:1.7 {:dependencies [[org.clojure/clojure "1.7.0"]]}
-             :1.8 {:dependencies [[org.clojure/clojure "1.8.0"]]}
-             :dev {:dependencies [[criterium "0.4.4"]]}}
+  :profiles {:1.7  {:dependencies [[org.clojure/clojure "1.7.0"]]}
+             :1.8  {:dependencies [[org.clojure/clojure "1.8.0"]]}
+             :1.9  {:dependencies [[org.clojure/clojure "1.9.0-alpha10"]]}
+             :dev  {:dependencies [[criterium "0.4.4"]]}
+             :lein {:dependencies [[leiningen "2.6.1"]]}}
   ;; Part of release is currently manual; copy target/docs to the AvisoNovate/docs/pretty folder
   :aliases {"release" ["do"
                        "clean,"

src/pretty/plugin.clj

@@ -1,19 +1,33 @@
 (ns pretty.plugin
   "A plugin for Leiningen that automatically enables pretty printing."
   {:added "0.1.19"}
-  (:require [io.aviso.repl :as repl]))
+  (:require [io.aviso.repl :as repl]
+            [leiningen.core.main :as main]))
 
 (defn hooks
   "Enables pretty printing of exceptions within Leiningen. This is evaluated in the Leinigen classpath, not the project's
   (if any)."
   []
   (repl/install-pretty-exceptions))
 
+
+(def ^:private warning (atom true))
+
 (defn middleware
   "Automatically adds the :injections that enable Pretty."
   [project]
-  (update-in project [:injections]
-             (fnil into [])
-             ['(require 'io.aviso.repl)
-              '(io.aviso.repl/install-pretty-exceptions)]))
+  (if (contains? (->> project
+                      :dependencies
+                      (map first)
+                      set)
+                 'io.aviso/pretty)
+    (update-in project [:injections]
+               (fnil into [])
+               ['(require 'io.aviso.repl)
+                '(io.aviso.repl/install-pretty-exceptions)])
+    (do
+      ;; Ugly! But necessary since middleware gets invoked more than once for some unknown reason.
+      (when (compare-and-set! warning true false)
+        (main/warn "Unable to enable pretty exception reporting, as io.aviso/pretty is not a project dependency."))
+      project)))