python · colesbury · Apr 29, 2024 · Apr 26, 2024 · Apr 26, 2024 · Apr 27, 2024
@@ -10,6 +10,7 @@
 import threading
 import time
 import random
+import textwrap

 from test import support
 from test.support import script_helper, ALWAYS_EQ
@@ -1009,6 +1010,31 @@ def __del__(self): pass
        del x
        support.gc_collect()

+    @support.cpython_only
+    def test_no_memory_when_clearing(self):
+        # gh-118331: Make sure we do not raise an exception from the destructor
+        # when clearing weakrefs if allocating the intermediate tuple fails.
+        code = textwrap.dedent("""
+        import _testcapi
+        import weakref
+
+        class TestObj:
+            pass
+
+        def callback(obj):
+            pass
+
+        obj = TestObj()
+        # The choice of 50 is arbitrary, but must be large enough to ensure
+        # the allocation won't be serviced by the free list.
+        wrs = [weakref.ref(obj, callback) for _ in range(50)]
+        _testcapi.set_nomemory(0)
+        del obj
+        """).strip()
+        res, _ = script_helper.run_python_until_end("-c", code)
+        stderr = res.err.decode("ascii", "backslashreplace")
+        self.assertNotRegex(stderr, "_Py_Dealloc: Deallocator of type 'TestObj'")
+

 class SubclassableWeakrefTestCase(TestBase):


@@ -1016,7 +1016,9 @@ PyObject_ClearWeakRefs(PyObject *object)
    PyObject *exc = PyErr_GetRaisedException();
    PyObject *tuple = PyTuple_New(num_weakrefs * 2);
    if (tuple == NULL) {
-        _PyErr_ChainExceptions1(exc);
+        _PyWeakref_ClearWeakRefsExceptCallbacks(object);
+        PyErr_WriteUnraisable(NULL);
+        PyErr_SetRaisedException(exc);
        return;
    }