[Python] Why doesn't len(obj) go through __getattribute__, and how can I override this...

I've noticed that calling obj.__len__() explicitly goes through obj.__getattribute__("__len__"), but calling len(obj) does not. A quick search suggests that built - in functions like len(), dir(), and repr() optimize their calls by accessing attributes directly via the object's internal structure rather than going through __getattribute__, except when dealing with private attributes.

Even if I clear obj.__dict__, len(obj) still bypasses __getattribute__. I also tried overriding obj.__dir__() and removing all dunder methods it returns, but len(obj) still avoids __getattribute__.

Is there any way to override this behavior and force len(obj) (and the others) to go through __getattribute__("__len__")?

Exaple:

class Custom:
def __getattribute__(self, item):
print(f"Accessing: {item}")
return super().__getattribute__(item)

def __len__(self):
return 50

obj = Custom()

print(obj.__len__()) # Triggers __getattribute__
print(len(obj)) # Bypasses __getattribute__


Output:

Accessing: __len__
50
50 # No `Accessing: __len__` message, meaning __getattribute__ was bypassed

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