std::list leaks memory while std::vector does not

[saraedum]

The following quickly eats through my RAM:

import cppyy
cppyy.cppdef(r"""
#include <list>
std::list<int> f() { return std::list<int>(3); }
""")
while True: _ = list(cppyy.gbl.f())

However, if I replace list with vector, memory consumption is stable.

---

This is with cppyy 3.1.2 from conda-forge on x86_64 Arch Linux.

[saraedum]

Same with a pip installed cppyy 3.1.2.

[wlav]

Fixed in repo (and leak check test added). The reason for the difference between list and vector is that std::vector has its own ("high performance") iterator. The cause was an incorrect lifeline direction (causing a circular dependency) in the generic STL iterator protocol, which was unnecessary anyway b/c the iterator pythonization already added a lifeline.