Iterating over ctypes pointer causes hang or segmentation fault

Trying to create iterable (list, tuple, set etc.) from PyCPointer instance leads to hang or segmentation fault.
This code causes hang and memory leak which goes until oom-killer kills python process:

import ctypes
x = ctypes.c_int32(12345)
buf4_p_t = ctypes.POINTER(ctypes.ARRAY(ctypes.c_byte, 4))
buf_p = ctypes.cast(ctypes.byref(x), buf4_p_t)
list(buf_p)

Similar code that causes segmentation fault:

import ctypes
x = ctypes.c_int32(54321)
xp = ctypes.pointer(x)
list(xp)

Iterating over pointer using for statement leads to an infinite loop:
for i in buf_p: print(i)
for i in xp: print(i)
list(for i in buf_p)

Tried on 3.10.3 and 3.11.0a6+, fails at both.

The possible reason is that PyCPointer_Type defines sq_item without defining tp_iter.
Despite I can't imagine any reason why anyone might need to use pointer as iterable/sequence, raising TypeError in such situation would be a better option.

Linked PRs

• gh-126318
• gh-157801

Comece com o comportamento de ctypes PyCPointer mostrado nas duas reproduções e confirme o travamento, o crescimento de memória e o segmentation fault nas versões afetadas do Python. Rastreie como a indexação de ponteiros e a iteração interagem e, em seguida, verifique se o comportamento concluído rejeita a iteração com segurança, sem travar nem causar um crash; as PRs vinculadas gh-126318 e gh-157801 fornecem trabalho existente para inspeção.