Add additional tests for STORE_ATTR.

Author: nascheme

Lib/test/test_free_threading/test_races.py

@@ -4,6 +4,7 @@
 import threading
 import time
 import unittest
+import _testinternalcapi
 
 from test.support import threading_helper
 
@@ -235,6 +236,39 @@ def mutate():
 
         do_race(read, mutate)
 
+    def make_shared_key_dict(self):
+        class C:
+            pass
+
+        a = C()
+        a.x = 1
+        return a.__dict__
+
+    def test_racing_store_attr_dict(self):
+        class C:
+            pass
+
+        c = C()
+
+        def set_value():
+            for i in range(20):
+                c.x = i
+
+        def mutate():
+            nonlocal c
+            c.x = 1
+            self.assertTrue(_testinternalcapi.has_inline_values(c))
+            for i in range(30):
+                setattr(c, f"_{i}", None)
+            self.assertFalse(_testinternalcapi.has_inline_values(c.__dict__))
+            c.__dict__ = self.make_shared_key_dict()
+            self.assertTrue(_testinternalcapi.has_split_table(c.__dict__))
+            c.__dict__[1] = None
+            self.assertFalse(_testinternalcapi.has_split_table(c.__dict__))
+            c = C()
+
+        do_race(set_value, mutate)
+
 
 if __name__ == "__main__":
     unittest.main()

Modules/_testinternalcapi.c

@@ -1989,6 +1989,14 @@ has_inline_values(PyObject *self, PyObject *obj)
     Py_RETURN_FALSE;
 }
 
+static PyObject *
+has_split_table(PyObject *self, PyObject *obj)
+{
+    if (PyDict_Check(obj) && _PyDict_HasSplitTable((PyDictObject *)obj)) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
 
 // Circumvents standard version assignment machinery - use with caution and only on
 // short-lived heap types
@@ -2139,6 +2147,7 @@ static PyMethodDef module_functions[] = {
     {"get_rare_event_counters", get_rare_event_counters, METH_NOARGS},
     {"reset_rare_event_counters", reset_rare_event_counters, METH_NOARGS},
     {"has_inline_values", has_inline_values, METH_O},
+    {"has_split_table", has_split_table, METH_O},
     {"type_assign_specific_version_unsafe", type_assign_specific_version_unsafe, METH_VARARGS,
      PyDoc_STR("forcefully assign type->tp_version_tag")},