make let-flow wait on all bound values, fix #118

ztellman · ztellman · commit 651594c6b3dd · 2018-05-17T15:51:37.000-07:00
diff --git a/src/manifold/deferred.clj b/src/manifold/deferred.clj
@@ -1306,12 +1306,14 @@
                                       (back-references marker form)))
                                   (range))))
         binding-dep?        (->> gensym->deps vals (apply concat) set)
+
         body-dep?           (->> `(let [~@(interleave
                                             vars'
                                             (repeat nil))]
                                     ~@body)
                               (back-references marker)
                               (map (zipmap vars' gensyms))
+                              (concat (drop (count vars) gensyms))
                               set)
         dep?                (set/union binding-dep? body-dep?)]
     `(let [executor# (manifold.executor/executor)]
diff --git a/test/manifold/deferred_test.clj b/test/manifold/deferred_test.clj
@@ -73,6 +73,15 @@
            (d/catch ArithmeticException (constantly :foo))))))
 
 (deftest test-let-flow
+
+  (let [flag (atom false)]
+    @(let [z (clojure.core/future 1)]
+       (d/let-flow [x (d/future (clojure.core/future z))
+                    _ (d/future (Thread/sleep 1000) (reset! flag true))
+                    y (d/future (+ z x))]
+         (d/future (+ x x y z))))
+    (is (= true @flag)))
+
   (is (= 5
         @(let [z (clojure.core/future 1)]
            (d/let-flow [x (d/future (clojure.core/future z))
