Fix unescape-unicode edge case with multiple backslashes

Author: chage

src/com/walmartlabs/lacinia/parser/common.clj

@@ -54,8 +54,12 @@
   (-> v
       ;; Because of how parsing works, the string literal includes the enclosing quotes
       (subs 1 (dec (.length v)))
-      (str/replace #"\\([\\\"\/bfnrt])" #(unescape-ascii (second %)))
-      (str/replace #"\\u([A-Fa-f0-9]{4})" #(unescape-unicode (second %)))))
+      (str/replace #"\\(\\|u[A-Fa-f0-9]{4}|[\"\/bfnrt])"
+                   #(let [s (second %)]
+                      (cond
+                        (= s "\\") "\\"
+                        (= (first s) \u) (unescape-unicode (subs s 1))
+                        :else (unescape-ascii s))))))
 
 (defn ^:private indent-of
   [s]

test/com/walmartlabs/lacinia/parser/query_test.clj

@@ -73,7 +73,12 @@
   (testing "unicode"
     (is (= {:id "1138"
             :newHomePlanet "❄ＨＯＴＨ❄"}
-           (args "mutation { changeHeroHomePlanet(id: \"1138\", newHomePlanet: \"\\u2744\\uff28\\uff2f\\uff34\\uff28\\u2744\") {name}}")))))
+           (args "mutation { changeHeroHomePlanet(id: \"1138\", newHomePlanet: \"\\u2744\\uff28\\uff2f\\uff34\\uff28\\u2744\") {name}}"))))
+
+  (testing "not unicode"
+    (is (= {:id "1139"
+            :newHomePlanet "\\u2744\\uff28\\uff2f\\uff34\\uff28\\u2744"}
+           (args "mutation { changeHeroHomePlanet(id: \"1139\", newHomePlanet: \"\\\\u2744\\\\uff28\\\\uff2f\\\\uff34\\\\uff28\\\\u2744\") {name}}")))))
 
 (deftest query-reserved-word
   ;; Use 'query', 'mutation', and 'subscription' in various unusual places.