On Mon, Sep 5, 2016 at 11:48 AM, Ben Finney <ben+pyt...@benfinney.id.au> wrote: > The larger point which remains true: Don't think of ‘__init__’ as a > constructor, all it does is work on an *already-constructed* instance. > > The ‘__new__’ method is the constructor. The instance doesn't exist > before that method is called; if successful, the instance is constructed > and returned. > > The ‘__init__’ method is the initialiser. It receives the > already-constructed instance, and returns ‘None’. That doesn't affect > existing references to the instance.
It doesn't really matter, though. Here's the outside view of constructing a class: instance = Class() Doesn't matter how it's implemented; you call something and you either get an instance back, or catch an exception. While it's technically true that __init__ raising an exception won't affect existing references to that instance, it's almost immaterial. You generally won't implement __new__ to retain refs, and you generally won't call __init__ again after the instance has been fully constructed. Generally, you can assume that an exception in __init__ means you can safely dispose of the object. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
