CLJS-1721: 3-arity get-in fails on types which do not implement ILookup

Author: dnolen

src/main/cljs/cljs/core.cljs

@@ -4798,13 +4798,11 @@ reduces them without incurring seq initialization"
      (loop [sentinel lookup-sentinel
             m m
             ks (seq ks)]
-       (if ks
-         (if (not (satisfies? ILookup m))
-           not-found
-           (let [m (get m (first ks) sentinel)]
-             (if (identical? sentinel m)
-               not-found
-               (recur sentinel m (next ks)))))
+       (if-not (nil? ks)
+         (let [m (get m (first ks) sentinel)]
+           (if (identical? sentinel m)
+             not-found
+             (recur sentinel m (next ks))))
          m))))
 
 (defn assoc-in

src/test/cljs/cljs/core_test.cljs

@@ -3210,6 +3210,12 @@
   (is (zero? (hash-string nil)))
   (is (not (zero? (hash-string "null")))))
 
+(deftest test-cljs-1721
+  (is (= 1          (get-in {:a (array 1 2 3 4)} [:a 0] :not-found)))
+  (is (= :not-found (get-in {:a (array 1 2 3 4)} [:a 4] :not-found)))
+  (is (= "d"        (get-in {:a "data"} [:a 0] :not-found)))
+  (is (= :not-found (get-in {:a "data"} [:a 4] :not-found))))
+
 (comment
   ;; ObjMap
   ;; (let [ks (map (partial str "foo") (range 500))