I am debugging some complicated legacy Python3 code and find myself needing to know, at a particular point in the executing code, all the try blocks that are active in the call stack. Is there a way to introspect and print out the nested tree?

So, for example, we might have this code:

def fn1():
    try:
        fn2()
    except IOError:
        # do something

def fn2():
    try:
        fn3()
    except NameError:
        # do something

def fn3():
    print( **YourAnswerHere** )

The idea is that if I invoke fn1() then the print statement in fn3 would produce something like:

    fn1: try / except IOError
        fn2: try / except NameError

If that’s not possible, I’d be able to get along if it merely printed [fn1 fn2]. Ideally it would handle try / finally blocks as well.

I could find nothing about this using Google. I looked at every occurrence of the word try in the documentation for Python’s inspect and traceback modules but found nothing. The ast module has classes related to try but I don’t have a clue how to use them and it looks like those are for analyzing static code, rather than executing code. Thank you.