Fix sorted map sentinel reference count

Author: hanke0

src/rbtree.c

@@ -568,20 +568,14 @@ static void RBTree_RemoveNode(CtsRBTree *tree, CtsRBTreeNode *node) {
   assert(root != sentinel);
   assert(node != sentinel);
   if (root == node && tree->length == 1) {
-    Py_INCREF(sentinel);
     tree->root = sentinel;
   } else {
     rbtree_delete(tree, node);
   }
 
+  Py_DECREF(sentinel);
   Py_DECREF(node->key);
   Py_DECREF(node->value);
-  if (node->left == tree->sentinel) {
-    Py_DECREF(tree->sentinel);
-  }
-  if (node->right == tree->sentinel) {
-    Py_DECREF(tree->sentinel);
-  }
   node->left = NULL;
   node->right = NULL;
   node->key = NULL;

tests/test_sortedmap.py

@@ -34,6 +34,9 @@ class TestSortedMap(unittest.TestCase):
     def assert_ref(self, o1, o2, msg=None):
         self.assertEqual(sys.getrefcount(o1), sys.getrefcount(o2), msg=msg)
 
+    def _create_sorted_map(self, cmp=None):
+        return ctools.SortedMap(cmp)
+
     def _build_v(self, seq):
         sorted_map = ctools.SortedMap()
         mapping = dict()
@@ -133,11 +136,6 @@ def test_contains(self):
             self.assertTrue(key2 in mapping)
             self.assert_ref(key2, key1)
 
-    def test_len(self):
-        seq = list(range(1024))
-        keys1, keys2, sorted_map, mapping = self._build_v(seq)
-        self.assertEqual(len(keys1), len(sorted_map))
-
     def _test_iter(self, name):
         seq = list(range(1024))
         random.shuffle(seq)
@@ -439,6 +437,29 @@ def test_max_min(self):
             k2 = keys2[i]
             self.assert_ref(k2, k1)
 
+    def test_len(self):
+        seq = list(range(1024))
+        s = self._create_sorted_map()
+        for i, v in enumerate(seq):
+            s[v] = v
+            self.assertEqual(i + 1, len(s))
+
+        total = len(seq)
+        for i, v in enumerate(seq):
+            del s[v]
+            self.assertEqual(total - i - 1, len(s))
+
+    def test_sentinel(self):
+        seq = list(range(1024))
+        s = self._create_sorted_map()
+        sentinel = _ctools.SortedMapSentinel
+        ref_count = sys.getrefcount(sentinel)
+        for i, v in enumerate(seq):
+            s[v] = v
+        for i, v in enumerate(seq):
+            del s[v]
+        self.assertEqual(ref_count, sys.getrefcount(sentinel))
+
 
 if __name__ == "__main__":
     unittest.main()