HBTreeFolder2: automatic prune trees that become empty after that an object is deleted

product/HBTreeFolder2/HBTreeFolder2.py

@@ -320,7 +320,9 @@ class HBTreeFolder2Base (Persistent):
         """Remove the named object from the folder.
         """
         htree = self._htree
+        h = []
         for sub_id in self.hashId(id)[:-1]:
+          h.append((htree, sub_id))
           htree = htree.get(sub_id)
           if type(htree) is not OOBTree:
             raise KeyError(id)
@@ -328,6 +330,9 @@ class HBTreeFolder2Base (Persistent):
           raise KeyError(id)
         del htree[id]
         self._count.change(-1)
+        while h and not htree:
+          htree, sub_id = h.pop()
+          del htree[sub_id]
 
     security.declareProtected(view_management_screens, 'getBatchObjectListing')
     def getBatchObjectListing(self, REQUEST=None):

product/HBTreeFolder2/tests/testHBTreeFolder2.py

@@ -53,8 +53,10 @@ class HBTreeFolder2Tests(ERP5TypeTestCase):
           self.assertRaises(KeyError, f._delOb, id)
         self.assertEqual(len(f), 1 + len(ok))
         self.assertEqual(f.getTreeIdList(), [None, "b", "c-a"])
+        self.assertEqual(len(f._htree), 4)
         for id in ok:
           f._delOb(id)
+        self.assertEqual(len(f._htree), 1)
         self.assertEqual(len(f), 1)
         self.assertEqual(f.getTreeIdList(), [None])
         self.assertEqual(ff.getTreeIdList(), [])