[Python-Dev] weak refs in descriptors (http://bugs.python.org/issue17950)

[Terry Jan Reedy]

On 5/13/2013 9:20 AM, Maciej Fijalkowski wrote:

> The strong reference there is a feature. Descriptors keep the class
> alive if somehow the class disappears and the descriptor itself does

Is this feature stated or implied in the reference manual?
3.3.2.1. Implementing Descriptors
3.3.2.2. Invoking Descriptors
???
or is it an implementation detail that people have come to rely on?