Feature or enhancement

When an object like socket.socket is used in with statement, NotImplementedError should be risen.

Pitch

The standard library has some classes that implement thin low-level wrappers but look and feel like manageable resources. For example, socket.socket has the same semantics as a file stream so a library user can conclude that an ability to use a file in with means that every openable I/O stream may be used in such a way.

However, it leads to hard to track bugs. A default behavior of __exit__ is to do nothing so we get untraceable resource leaks or stream deadlocks. For example, a server thread needs to close all of its sockets if an exception occurs (otherwise there will be a lonely server socket with a hanged client and a leaked owner thread).

According to documentation, the issue is solved by wrapping such an object into contextlib.closing but it comes in a hard postfactum way.

Anectotally, I was backlashed by this mismatch of a mental model trying to hunt down unstable tests in gh-92475 for some fruitless weeks.