Buffer class makes unexpected RPC calls

The Buffer class makes unexpected RPC calls.

This is due to the __len__ method being called during boolean tests.

For example, the following code will print 2.

class Example:
    def __len__(self) -> int:
        print(2)
        return 0


example = Example()

if example:
    pass

This is very surprising behaviour, and there is absoutely no way to fix it without breaking backwards compatibility.

But it should be documentated, because this will actually break your code if you are using Buffer class from another thread.

It took me a quite a bit of effort to figure out that an or statement was causing crashes in my plugin.

[blueyed]

It could also implement __bool__ itself (returning True always), couldn’t it? https://docs.python.org/3.8/reference/datamodel.html?highlight=__del__#object.__bool__

[justinmk]

PR welcome. We monkey-patch various things, this is more or less idiomatic in python land.