I was learning about other built-in class methods in Python and came across one called __del__(). Like __repr__() and __str__(), I believed it could be overriden and decided to test it.
Here is a basic class I created:
class SomeClass:
def __del__(self):
print("Deleted!")
Just to confirm this code works, here is me testing it in the console:
>>> test = SomeClass()
>>> del test
Deleted!
When running in the console, I tested it with x and y variables:
>>> x = SomeClass()
>>> y = x
>>> del x # This should print "Deleted!"
>>> del y
Deleted!
Strangely, when deleting x, it never outputted anything, but when deleting y, which was assigned to be equal to the x object, it outputted "Deleted!".
I didn't stop there, though. I tested this concept again, but now with a and b variables.
>>> a = SomeClass()
>>> b = a
>>> del a
>>> b # Check if b exists
<__main__.SomeClass instance at 0x7f98a1a67fc8>
>>> del b # Like previously, with 'y', this should print "Deleted!"
>>> globals() # Well, it didn't. Let's check all our global variables to confirm
Deleted!
{'__builtins__': <module '__builtin__' (built-in)>, 'SomeClass': <class __main__.SomeClass at 0x7f98a1a5f668>, '__package__': None, '__name__': '__main__', '__doc__': None}
As you can see, calling the humble globals() method seem to print "Deleted!" then printing the globals which contains no reference of b, so it did delete it.
How comes overriding the __del__ method causes odd issues? I thought of using the method to control what happens when certain objects in a game are deleted, but now it makes me less convinced, as odd bugs may occur when I duplicate objects and delete them.