michael@0: // One Debugger's onPop handler can remove another Debugger's onPop handler.
michael@0: var g = newGlobal();
michael@0: var dbg1 = new Debugger(g);
michael@0: var dbg2 = new Debugger(g);
michael@0: 
michael@0: var log;
michael@0: var frames = [];
michael@0: var firstPop = true;
michael@0: 
michael@0: function handleEnter(frame) {
michael@0:     log += '(';
michael@0:     frames.push(frame);
michael@0:     frame.onPop = function handlePop(completion) {
michael@0:         log += ')';
michael@0:         assertEq(completion.return, 42);
michael@0:         if (firstPop) {
michael@0:             // We can't say which frame's onPop handler will get called first.
michael@0:             if (this == frames[0])
michael@0:                 frames[1].onPop = undefined;
michael@0:             else
michael@0:                 frames[0].onPop = undefined;
michael@0:             gc();
michael@0:         } else {
michael@0:             assertEq("second pop handler was called",
michael@0:                      "second pop handler should not be called");
michael@0:         }
michael@0:         firstPop = false;
michael@0:     };
michael@0: };
michael@0: 
michael@0: dbg1.onEnterFrame = handleEnter;
michael@0: dbg2.onEnterFrame = handleEnter;
michael@0: 
michael@0: log = '';
michael@0: assertEq(g.eval('40 + 2'), 42);
michael@0: assertEq(log, '(()');