Bug 70605 – First stack frame when evaluating a script is missing

• Component: WebCore JavaScript
• Status: UNCONFIRMED

[Michael Schneider]

To reproduce
1) Open Safari on http://poshnet.ch/stack_test.html. It contains the script
   
   function foo()  {
     console.trace();
   }
   console.trace();
   foo();

2) Open the console

observe: the output is
 console.trace()
   (anonymous function)
 console.trace()
  foo

Note that the second trace is missing the bottom frame, the anonymous evaluate script. This is very confusing as it looks as if the browser invoked foo directly. Chrome shows the (anonymous function) stack frame in both cases.

This seems to be due to ScriptCallStackFactory.cpp:73

        if (function)
            functionName = asFunction(function)->name(exec);
        else {
            // Caller is unknown, but if frames is empty we should still add the frame, because
            // something called us, and gave us arguments.
            if (!frames.isEmpty())
                break;
        }

where anonymous frames (such as the script eval) are dropped if other stack frames are on top of it. What is the exact purpose of that "if"? If we can change that, ie. drop the else, I'm more than happy to provide a patch.