Preserve metadata on fn and action macros

Because they're macros, rx/fn and rx/action would lose metadata attached
to them, in particular type hints which are slightly important to
disambiguate overloaded Observable methods. Fixed.

Author: daveray

language-adaptors/rxjava-clojure/build.gradle

@@ -13,6 +13,7 @@ dependencies {
 
 tasks.compileExamplesClojure.classpath = files(tasks.compileClojure.destinationDir) + tasks.compileClojure.classpath
 
+clojureTest.dependsOn compileTestJava
 /*
  * Clojure
  */

language-adaptors/rxjava-clojure/src/main/clojure/rx/lang/clojure/interop.clj

@@ -66,11 +66,13 @@
 
   "
   [& fn-form]
+  ; preserve metadata so type hints work
   ; have to qualify fn*. Otherwise bad things happen with the fn* special form in clojure
-  `(rx.lang.clojure.interop/fn* (clojure.core/fn ~@fn-form)))
+  (with-meta `(rx.lang.clojure.interop/fn* (clojure.core/fn ~@fn-form))
+             (meta &form)))
 
 (defn action*
-  "Given function f, returns an object that implements rx.util.functions.Action0-9
+  "Given function f, returns an object that implements rx.util.functions.Action0-3
   by delegating to the given function.
 
   Example:
@@ -93,6 +95,8 @@
 
   "
   [& fn-form]
-  `(action* (clojure.core/fn ~@fn-form)))
+  ; preserve metadata so type hints work
+  (with-meta `(action* (clojure.core/fn ~@fn-form))
+             (meta &form)))
 
 ;################################################################################

language-adaptors/rxjava-clojure/src/test/clojure/rx/lang/clojure/interop_test.clj

@@ -3,7 +3,7 @@
             [clojure.test :refer [deftest testing is]])
   (:import [rx Observable]
            [rx.observables BlockingObservable]
-           ))
+           [rx.lang.clojure.interop DummyObservable]))
 
 (deftest test-fn*
   (testing "implements Func0-9"
@@ -27,12 +27,38 @@
       (is (= [1 2 3 4 5 6]       (.call f 1 2 3 4 5 6)))
       (is (= [1 2 3 4 5 6 7]     (.call f 1 2 3 4 5 6 7)))
       (is (= [1 2 3 4 5 6 7 8]   (.call f 1 2 3 4 5 6 7 8)))
-      (is (= [1 2 3 4 5 6 7 8 9] (.call f 1 2 3 4 5 6 7 8 9))))))
+      (is (= [1 2 3 4 5 6 7 8 9] (.call f 1 2 3 4 5 6 7 8 9)))))
+
+  (let [dummy (DummyObservable.)]
+    (testing "preserves metadata applied to form"
+      ; No type hint, picks Object overload
+      (is (= "Object"
+             (.call dummy (rx/fn* +))))
+      (is (= "rx.util.functions.Func1"
+             (.call dummy
+                    ^rx.util.functions.Func1 (rx/fn* +))))
+      (is (= "rx.util.functions.Func2"
+             (.call dummy
+                    ^rx.util.functions.Func2 (rx/fn* *)))))))
 
 (deftest test-fn
   (testing "makes appropriate Func*"
     (let [f (rx/fn [a b c] (println "test-fn") (+ a b c))]
-      (is (= 6 (.call f 1 2 3))))))
+      (is (= 6 (.call f 1 2 3)))))
+
+  (let [dummy (DummyObservable.)]
+    (testing "preserves metadata applied to form"
+      ; No type hint, picks Object overload
+      (is (= "Object"
+             (.call dummy
+                    (rx/fn [a] a))))
+      (is (= "rx.util.functions.Func1"
+             (.call dummy
+                    ^rx.util.functions.Func1 (rx/fn [a] a))))
+      (is (= "rx.util.functions.Func2"
+             (.call dummy
+                    ^rx.util.functions.Func2 (rx/fn [a b] (* a b))))))))
+
 
 (deftest test-fnN*
   (testing "implements FuncN"
@@ -51,14 +77,39 @@
       (.call a 1)
       (.call a 1 2)
       (.call a 1 2 3)
-      (is (= [[] [1] [1 2] [1 2 3]])))))
+      (is (= [[] [1] [1 2] [1 2 3]]))))
+  (let [dummy (DummyObservable.)]
+    (testing "preserves metadata applied to form"
+      ; no meta, picks Object overload
+      (is (= "Object"
+             (.call dummy
+                    (rx/action* println))))
+      (is (= "rx.util.functions.Action1"
+             (.call dummy
+                    ^rx.util.functions.Action1 (rx/action* println))))
+      (is (= "rx.util.functions.Action2"
+             (.call dummy
+                    ^rx.util.functions.Action2 (rx/action* prn)))))))
 
 (deftest test-action
   (testing "makes appropriate Action*"
     (let [called (atom nil)
           a (rx/action [a b] (reset! called [a b]))]
       (.call a 9 10)
-      (is (= [9 10] @called)))))
+      (is (= [9 10] @called))))
+
+  (let [dummy (DummyObservable.)]
+    (testing "preserves metadata applied to form"
+      ; no meta, picks Object overload
+      (is (= "Object"
+             (.call dummy
+                    (rx/action [a] a))))
+      (is (= "rx.util.functions.Action1"
+             (.call dummy
+                    ^rx.util.functions.Action1 (rx/action [a] a))))
+      (is (= "rx.util.functions.Action2"
+             (.call dummy
+                    ^rx.util.functions.Action2 (rx/action [a b] (* a b))))))))
 
 (deftest test-basic-usage
 

language-adaptors/rxjava-clojure/src/test/java/rx/lang/clojure/interop/DummyObservable.java

@@ -0,0 +1,42 @@
+/**
+ * Copyright 2013 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package rx.lang.clojure.interop;
+
+// Dummy class with some overloads to make sure that type hinting works
+// correctly with the fn and action macros. Used only for testing.
+public class DummyObservable {
+
+    public String call(Object f) {
+        return "Object";
+    }
+
+    public String call(rx.util.functions.Func1 f) {
+        return "rx.util.functions.Func1";
+    }
+
+    public String call(rx.util.functions.Func2 f) {
+        return "rx.util.functions.Func2";
+    }
+
+    public String call(rx.util.functions.Action1 f) {
+        return "rx.util.functions.Action1";
+    }
+
+    public String call(rx.util.functions.Action2 f) {
+        return "rx.util.functions.Action2";
+    }
+
+}