better error message on failed refer

Signed-off-by: Stuart Halloway <stu@thinkrelevance.com>

2 files changed, 25 insertions, 10 deletions

diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj
index 0a2a39ae..d1b4b8e4 100644
--- a/src/clj/clojure/core.clj
+++ b/src/clj/clojure/core.clj
@@ -3229,6 +3229,15 @@
   [ns]
   (filter-key val (partial instance? Class) (ns-map ns)))
 
+(defn ns-interns
+  "Returns a map of the intern mappings for the namespace."
+  {:added "1.0"}
+  [ns]
+  (let [ns (the-ns ns)]
+    (filter-key val (fn [^clojure.lang.Var v] (and (instance? clojure.lang.Var v)
+                                 (= ns (.ns v))))
+                (ns-map ns))))
+
 (defn refer
   "refers to all public vars of ns, subject to filters.
   filters can include at most one each of:
@@ -3256,7 +3265,10 @@
         (when-not (exclude sym)
           (let [v (nspublics sym)]
             (when-not v
-              (throw (new java.lang.IllegalAccessError (str sym " is not public"))))
+              (throw (new java.lang.IllegalAccessError
+                          (if (get (ns-interns ns) sym)
+                            (str sym " is not public")
+                            (str sym " does not exist")))))
             (. *ns* (refer (or (rename sym) sym) v)))))))
 
 (defn ns-refers
@@ -3268,15 +3280,6 @@
                                  (not= ns (.ns v))))
                 (ns-map ns))))
 
-(defn ns-interns
-  "Returns a map of the intern mappings for the namespace."
-  {:added "1.0"}
-  [ns]
-  (let [ns (the-ns ns)]
-    (filter-key val (fn [^clojure.lang.Var v] (and (instance? clojure.lang.Var v)
-                                 (= ns (.ns v))))
-                (ns-map ns))))
-
 (defn alias
   "Add an alias in the current namespace to another
   namespace. Arguments are two symbols: the alias to be used, and
diff --git a/test/clojure/test_clojure/ns_libs.clj b/test/clojure/test_clojure/ns_libs.clj
index 10844ded..e1217756 100644
--- a/test/clojure/test_clojure/ns_libs.clj
+++ b/test/clojure/test_clojure/ns_libs.clj
@@ -71,3 +71,15 @@
     (is (thrown? IllegalStateException
                  #"Integer already refers to: class java.lang.Integer"
                  (defrecord Integer [])))))
+
+(deftest refer-error-messages
+  (let [temp-ns (gensym)]
+    (binding [*ns* *ns*]
+      (in-ns temp-ns)
+      (eval '(def ^{:private true} hidden-var)))
+    (testing "referring to something that does not exist"
+      (is (thrown-with-msg? IllegalAccessError #"nonexistent-var does not exist"
+            (refer temp-ns :only '(nonexistent-var)))))
+    (testing "referring to something non-public"
+      (is (thrown-with-msg? IllegalAccessError #"hidden-var is not public"
+            (refer temp-ns :only '(hidden-var)))))))