timers: update now within listOnTimeout

Fixes #8133, #8105.

Author: loyd

lib/timers.js

@@ -97,12 +97,12 @@ function listOnTimeout() {
 
   debug('timeout callback %d', msecs);
 
-  var now = Timer.now();
-  debug('now: %s', now);
-
-  var diff, first, hasQueue, threw;
+  var now, diff, first, hasQueue, threw;
   while (first = L.peek(list)) {
+    now = Timer.now();
+    debug('now: %d', now);
     diff = now - first._idleStart;
+
     if (diff < msecs) {
       list.start(msecs - diff, 0);
       debug('%d list wait because diff is %d', msecs, diff);

test/simple/test-timers-busy.js

@@ -0,0 +1,48 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+
+var DELAY = 50;
+var WINDOW = 5;
+
+function nearly(a, b) {
+  if (Math.abs(a-b) > WINDOW)
+    assert.strictEqual(a, b);
+}
+
+function work(ms) {
+  var start = Date.now();
+  while (Date.now() - start < ms);
+}
+
+function test() {
+  var start = Date.now();
+  setTimeout(function() {
+    work(DELAY + 20);
+    setTimeout(function() {
+      nearly(DELAY*3+20, Date.now() - start);
+    }, DELAY);
+  }, DELAY);
+}
+
+test();