Is there way to break out of a series of function calls in python

Question

Not too sure if I am following best practices. In my class I have a __call__ that runs multiple class functions when called. In one of the functions, if an exception is met, I want to break out of the call such that the other functions do not run.

    def __call__(self,event):
        self.f1(event)
        self.f2()
        self.f3()
        self.f4()
        self.f5()
        self.f6()

in one of the functions I have some logic

def f2(self):
    try:
        somelogic
    except otherlogic as error:
        doSomeOtherStuff

when an exception is caught in f2, I do not want to continue the call to f3,f4, etc.

If I am not using object calls correctly I am open to alternatives

Answer 1

I think the easiest way is to re-raise the exception in f2, ie

def f2(self):
    try:
        somelogic
    except otherlogic as error:
        doSomeOtherStuff
        raise

You may then want to handle this _ call _ ie

def __call__(self,event):
    try
        self.f1(event)
        self.f2()
        self.f3()
        self.f4()
        self.f5()
        self.f6()
    except:
        do_something

Answer 2

There's a couple of options.

1. Have each function raise an exception if "an exception is met".
2. Have the functions return a successful bit.

For the first option, you'd wrap the entire call list in a try/except block like this:

try:
    self.f1(event)
    self.f2
    ...
except MyCustomException:
    pass

For the second option you'd call them like:

if not self.f1(event):
    return
if not self.f2():
    return
...

Answer 3

I think an easier route is storing all your functions in a list and then running through a for loop. If you run into an exception, you break from the for loop.

I would also recommend not messing around with the dunder method __call__ unless you have a good reason. Calling 6 functions when calling an object is not necessarily intuitive and may lead to other developers not understanding what's happening when working with your code. As an alternative, call a function directly instead. In my example here, I am calling it start_process .

from typing import Callable, List


def start_process() -> None:
    list_of_functions: List[Callable] = [f1, f2, f3, f4, f5, f6]

    for fn in list_of_functions:
        try:
            fn()
        except Exception:
            break
    
    # do other logic