add test

python · zooba · Jun 11, 2024 · Jun 6, 2024 · Jun 6, 2024 · Jun 7, 2024
commit bda9545ac413922c49b91fad870e12990258ffac
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
@@ -400,8 +400,11 @@ PyAPI_FUNC(PyStatus) _PyInterpreterState_New(
 
 #define RARE_EVENT_INTERP_INC(interp, name) \
     do { \
-        /* saturating add */ \
-        if (interp->rare_events.name < UINT8_MAX) interp->rare_events.name++; \
+        /* saturating add */                \
+        int val = FT_ATOMIC_LOAD_UINT8_RELAXED(interp->rare_events.name); \
+        if (val < UINT8_MAX) { \
+            FT_ATOMIC_STORE_UINT8_RELAXED(interp->rare_events.name, val+1); \
+        } \
         RARE_EVENT_STAT_INC(name); \
     } while (0); \
 

diff --git a/Lib/test/test_free_threading/test_type.py b/Lib/test/test_free_threading/test_type.py
@@ -1,3 +1,4 @@
+import threading
 import unittest
 
 from concurrent.futures import ThreadPoolExecutor
@@ -95,6 +96,32 @@ def reader_func():
 
         self.run_one(writer_func, reader_func)
 
+    def test___class___modification(self):
+        class Foo:
+            pass
+
+        class Bar:
+            pass
+
+        thing = Foo()
+        def work():
+            foo = thing
+            for _ in range(10000):
+                foo.__class__ = Bar
+                type(foo)
+                foo.__class__ = Foo
+                type(foo)
+
+
+        threads = []
+        for i in range(NTHREADS):
+            thread = threading.Thread(target=work)
+            thread.start()
+            threads.append(thread)
+
+        for thread in threads:
+            thread.join()
+
     def run_one(self, writer_func, reader_func):
         writer = Thread(target=writer_func)
         readers = []