How to catch and exception in a loaded SWF's global$init? - actionscript-3

Question

My Flash program's loading a SWF that contains user code which has been compiled in real time. Because it's user code, it may throw exceptions. Unfortunately, I can't seem to catch the exceptions. This code doesn't work:
this._loader = new Loader();
this._loader.uncaughtErrorEvents.addEventListener(UncaughtErrorEvent.UNCAUGHT_ERROR, onUncaughtError);
this._loader.contentLoaderInfo.addEventListener(Event.COMPLETE, swfCompleteHandler);
this._loader.loadBytes(swfByteArray, loaderContext);
However, the debug player shows this in the unhandled exception dialog:
[Fault] exception, information=Error: Test error message
at global$init() [User_Code:3]
How do I catch an exception in global$init() of a loaded SWF? I've tried adding UNCAUGHT_ERROR event listeners to every loader and loaderInfo I can find... but none of them trigger when the exception is thrown from the loaded SWF's global$init(). Thanks in advance.

Answer 1

In cases where I could, I injected a try/catch into the user's code. For example, if the user code is simply:
trace("Hello");
My program modifies the code string to be:
try {
trace("Hello");
catch (Error error) { DoSomething(); }
However, this doesn't always work. For example, if the users' code is:
function output():void
{
throw new Error("Error!");
}
output();
Then the trick above doesn't work. Instead, I inject code like so:
startUserCode();
function output():void
{
throw new Error("Error!");
}
output();
endUserCode();
If endUserCode() doesn't get hit, I assume that an exception was thrown. I just don't know what exception. A nasty user could insert a random "return" into their code and endUserCode won't get hit but that's an edge case I decided to simply not handle.