Crash report

What happened?

When usingctypes with a function which returns aPyObject *, usingrestypectypes.py_object, and the function returnsNULL, there's aPy_DECREF of the result, leading to a segfault:

importctypesPyErr_Occurred=ctypes.pythonapi.PyErr_OccurredPyErr_Occurred.argtypes= []PyErr_Occurred.restype=ctypes.py_objectPyErr_Occurred()

The issue lies inGetResult: whenO_get is the result handler, it callsPy_DECREF on the result value, even though that can beNULL.O_get handles theNULL case correctly, setting an exception if none was set, and passing on theNULL. Code after thePy_DECREF inGetResult also handles theNULL case correctly, so changing thePy_DECREF into aPy_XDECREF makes things work.

Pull request incoming.

CPython versions tested on:

CPython 3.10, CPython 3.13, CPython main branch

Operating systems tested on:

Linux

Output from running 'python -VV' on the command line:

Python 3.14.0a7+ (heads/main-dirty:deda47d6e18, Apr 11 2025, 20:18:59) [GCC 14.2.1 20240912 (Red Hat 14.2.1-3)]

Linked PRs

• GH-132417: ctypes: Fix potential Py_DECREF(NULL) in py_object handling #132418
• [3.13] GH-132417: ctypes: Fix potentialPy_DECREF(NULL) when handling functions returningPyObject * (GH-132418) #132425