Do Not Allow Static Objects to be Deallocated

The runtime currently has many objects that are statically defined. See Include/internal/pycore_global_objects.h. For the singletons, all instances of the type are statically defined. Otherwise only some instances are.

The problem is that if tp_dealloc() for one of the affected types tries to free a static object then it will crash. We've set the refcount for such objects to a really high number to avoid this, but it is still possible. The risk rises a bit for immortal objects (see PEP 683).

For all types with static objects, we need to add a check in tp_dealloc() to either fail or reset the refcount to the really high number. We already have a check like this for the singletons and for str. For the other types we need to identify if the object is static and respond accordingly. The catch is that identifying that can be expensive, which is problematic for types that are deallocated frequently.

從 Include/internal/pycore_global_objects.h 開始，盤點靜態定義的物件，然後檢查受影響型別的 tp_dealloc 實作。確定每個型別如何在不產生不可接受的釋放負擔下識別靜態物件；完成的標準是靜態物件無法被釋放，也不會導致與 refcount 相關的當機。