Debugging spaghetti code

As a programmer, sometimes you find yourself dealing with this nasty badly written code and your task is to fix some even nastier and ugly looking bugs.

Whether is code you wrote yourself some years ago or someone else's (which makes it even worse) as it's your task to dig into the code, you will need help, help to understand where in heaven one of the dozens of public methods in that class is being called.

Yeah, in that code, almost all the methods in all the classes (including the main one) are public and of course is highly coupled making it almost impossible to read or to maintain.

Spaghetti code, hundreds of messy lines of 'code' (?) in each messy class... oh the joy...
After hours of work, after cursing everyone around you, you find the function which is causing the issue but... where is it being called? who's calling it? why?
Here it comes Stack Trace to the rescue! woohoo!
And the line of actionscript 3 that has saved me from cursing even the ones that are not around me is:

trace(new Error().getStackTrace());

That line will output in the flashlog the path (including class names, and code lines) that the thread takes before throwing the error (you will need flash player debugger to see the error). Now we now where the function is being called, time to continue debugging...

*Image taken from SpreadShirt.co.uk.