externs inference test wip

Author: swannodette

src/main/clojure/cljs/analyzer.cljc

@@ -798,10 +798,10 @@
          (not me) false
          :else
          (let [seen' (conj seen x)
-               [x' externs'] me]
-           (if-some [tag (-> x' meta :tag)]
-             (let [pre' (into [] (map symbol)
-                          (string/split (str (alias->type tag tag)) #"\."))]
+               [x' externs'] me
+               xmeta (meta x')]
+           (if (and (= 'Function (:tag xmeta)) (:ctor xmeta))
+             (let [pre' [(:ctor xmeta)]]
                (or (has-extern?* (into pre' (next pre)) top top seen')
                    (has-extern?* (into (conj pre' 'prototype) (next pre)) top top seen')))
              (recur (next pre) externs' top seen'))))))))

src/main/clojure/cljs/externs.clj

@@ -39,7 +39,10 @@
         (if-let [^JSTypeExpression ty (.getType info)]
           {:tag (get-type* ty)}
           (if (or (.isConstructor info) (.isInterface info))
-            {:tag 'Function}
+            (let [qname (symbol (.. node getFirstChild getQualifiedName))]
+              (cond-> {:tag 'Function}
+                (.isConstructor info) (merge {:ctor qname})
+                (.isInterface info) (merge {:iface qname})))
             (if (.hasReturnType info)
               {:tag 'Function
                :ret-tag (get-type* (.getReturnType info))})))))))

src/test/clojure/cljs/analyzer_tests.clj

@@ -619,6 +619,22 @@
                    '(let [y 1] (def y 2))))]
     (is (some? (-> parsed :expr :ret :var-ast)))))
 
+(deftest test-infer-externs-basic
+  (let [externs (externs/externs-map
+                  (closure/load-externs
+                    {:externs ["src/test/externs/test.js"]
+                     :use-only-custom-externs true}))]
+    (is (true? (a/has-extern? '[Foo] externs)))
+    (is (false? (a/has-extern? '[foo] externs)))
+    (is (true? (a/has-extern? '[baz] externs)))
+    (is (false? (a/has-extern? '[Baz] externs)))))
+
+(deftest test-infer-externs-default
+  (let [externs (externs/externs-map)]
+    (is (true? (a/has-extern? '[console] externs)))
+    (is (true? (a/has-extern? '[console log] externs)))
+    (is (true? (a/has-extern? '[Number isNaN] externs)))))
+
 (comment
   (require '[cljs.compiler :as cc])
   (require '[cljs.closure :as closure])
@@ -673,6 +689,12 @@
           (map (comp :externs second)
             (get @test-cenv ::a/namespaces))))))
 
+  (a/has-extern?* '[baz]
+    (externs/externs-map
+      (closure/load-externs
+        {:externs ["src/test/externs/test.js"]
+         :use-only-custom-externs true})))
+
   ;; works, does not generate extern
   (let [test-cenv (atom {::a/externs (externs/externs-map
                                        (closure/load-externs