The Tor Browser / file revision

 // A frame's onPop handler is called only once, even if it is for a function

 // called from a loop.

 var g = newGlobal();

 var dbg = new Debugger(g);

 var log;

 var count;

 dbg.onDebuggerStatement = function handleDebug(frame) {

     log += 'd';

     assertEq(frame.type, "call");

     count++;

     if (count == 10) {

         frame.onPop = function handlePop(c) {

             log += ')' + this.arguments[0];

             assertEq(c.return, "snifter");

         };

     }

 };

 g.eval("function f(n) { debugger; return 'snifter'; }");

 log = '';

 count = 0;

 g.eval("for (i = 0; i < 20; i++) f(i);");

 assertEq(count, 20);

 assertEq(log, "dddddddddd)9dddddddddd");