From f26aa001ebc8ae2bd8d4dcf03635931c6fb2a516 Mon Sep 17 00:00:00 2001
From: Nathan Marz <nathan@nathanmarz.com>
Date: Sat, 11 Jun 2016 09:51:28 -0400
Subject: [PATCH] make MAP-VALS work on nil

---
 src/clj/com/rpl/specter/impl.cljx   | 5 +++++
 test/com/rpl/specter/core_test.cljx | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/src/clj/com/rpl/specter/impl.cljx b/src/clj/com/rpl/specter/impl.cljx
index 2bce1a1..f440efa 100644
--- a/src/clj/com/rpl/specter/impl.cljx
+++ b/src/clj/com/rpl/specter/impl.cljx
@@ -907,6 +907,11 @@
     structure))
 
 (extend-protocol MapValsTransformProtocol
+  nil
+  (map-vals-transform [structure next-fn]
+    nil
+    )
+
   #+clj clojure.lang.PersistentArrayMap #+cljs cljs.core/PersistentArrayMap
   (map-vals-transform [structure next-fn]
     (map-vals-non-transient-transform structure {} next-fn)
diff --git a/test/com/rpl/specter/core_test.cljx b/test/com/rpl/specter/core_test.cljx
index 2e7511c..b4cb852 100644
--- a/test/com/rpl/specter/core_test.cljx
+++ b/test/com/rpl/specter/core_test.cljx
@@ -1202,6 +1202,11 @@
   (is (empty? (select s/ALL nil)))
   )
 
+(deftest map-vals-nil
+  (is (= nil (transform s/MAP-VALS inc nil)))
+  (is (empty? (select s/MAP-VALS nil)))
+  )
+
 (defspec dispense-test
   (for-all+
     [k1 gen/int