[Truffle] Make sure to really poll once.

* Even if timeout allowed is short or there are many interrupts.
jruby · Jul 25, 2015 · c9a1f69 · c9a1f69
1 parent 64a4164
commit c9a1f69
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/core/QueueNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/core/QueueNodes.java
@@ -159,7 +159,13 @@ public Object block() throws InterruptedException {
                     long now = System.currentTimeMillis();
                     long waited = now - start;
                     if (waited >= durationInMillis) {
-                        return false;
+                        // Try again to make sure we at least tried once
+                        final Object result = queue.poll();
+                        if (result == null) {
+                            return false;
+                        } else {
+                            return result;
+                        }
                     }
 
                     final Object result = queue.poll(durationInMillis, TimeUnit.MILLISECONDS);