Which Python memory‑leak patterns persist in CPython 3.12?

Goal: Identify the exact memory‑leak scenarios that remain in CPython 3.12 when reference cycles involve objects that define a __del__ method.

Constraints: CPython’s garbage collector does not automatically break cycles that contain __del__ methods, potentially leaving objects alive until the interpreter exits. This behavior is documented but not universally understood.

Uncertainty: It is unclear whether CPython should automatically reclaim such cycles or rely on developers to intervene, for example by using weakref.finalize or removing __del__ entirely.

Specific questions:

• Does CPython currently reclaim memory for reference cycles that contain __del__ methods?
• What is the measurable impact of applying weakref.finalize to break these cycles on overall memory usage?
• Which usage patterns still lead to apparent leaks despite these fixes?