pythongh-91051: fix segfault when using all 8 type watchers

carljm · carljm · commit 1980789e13a3 · 2023-08-10T17:30:48.000-07:00
diff --git a/Include/cpython/object.h b/Include/cpython/object.h
@@ -227,7 +227,7 @@ struct _typeobject {
     vectorcallfunc tp_vectorcall;
 
     /* bitset of which type-watchers care about this type */
-    char tp_watched;
+    unsigned char tp_watched;
 };
 
 /* This struct is used by the specializer
diff --git a/Lib/test/test_capi/test_watchers.py b/Lib/test/test_capi/test_watchers.py
@@ -294,6 +294,16 @@ class C2: pass
                 C2.hmm = "baz"
                 self.assert_events([C1, [C2]])
 
+    def test_all_watchers(self):
+        class C: pass
+        with ExitStack() as stack:
+            last_wid = -1
+            while last_wid < self.TYPE_MAX_WATCHERS - 1:
+                last_wid = stack.enter_context(self.watcher())
+            self.watch(last_wid, C)
+            C.foo = "bar"
+            self.assert_events([C])
+
     def test_watch_non_type(self):
         with self.watcher() as wid:
             with self.assertRaisesRegex(ValueError, r"Cannot watch non-type"):
