gh-118331: Fix a couple of issues when list allocation fails

Lib/test/test_list.py

@@ -1,6 +1,9 @@
 import sys
-from test import list_tests
+import textwrap
+from test import list_tests, support
 from test.support import cpython_only
+from test.support.import_helper import import_module
+from test.support.script_helper import assert_python_failure
 import pickle
 import unittest
 
@@ -309,5 +312,20 @@ def test_tier2_invalidates_iterator(self):
             a.append(4)
             self.assertEqual(list(it), [])
 
+    @support.cpython_only
+    def test_no_memory(self):
+        # gh-118331: Make sure we don't crash if list allocation fails
+        import_module("_testcapi")
+        code = textwrap.dedent("""
+        import _testcapi, sys
+        # Prime the freelist
+        l = [None]
+        del l
+        _testcapi.set_nomemory(0)
+        l = [None]
+        """)
+        _, _, err = assert_python_failure("-c", code)
+        self.assertIn("MemoryError", err.decode("utf-8"))
+
 if __name__ == "__main__":
     unittest.main()

Objects/listobject.c

@@ -533,6 +533,7 @@ list_dealloc(PyObject *self)
             Py_XDECREF(op->ob_item[i]);
         }
         free_list_items(op->ob_item, false);
+        op->ob_item = NULL;
     }
     if (PyList_CheckExact(op)) {
         _Py_FREELIST_FREE(lists, op, PyObject_GC_Del);

Tools/cases_generator/analyzer.py

@@ -632,7 +632,6 @@ def has_error_without_pop(op: parser.CodeDef) -> bool:
     "_PyGen_GetGeneratorFromFrame",
     "_PyInterpreterState_GET",
     "_PyList_AppendTakeRef",
-    "_PyList_FromStackRefStealOnSuccess",
     "_PyList_ITEMS",
     "_PyLong_CompactValue",
     "_PyLong_DigitCount",