Remove old index entries when path changes

CHANGES.rst

@@ -26,6 +26,10 @@ Bug fixes
   many indexed objects
   (`#39 <https://github.com/zopefoundation/Products.ZCatalog/issues/39>`_)
 
+- Make sure ``PathIndex._index_object`` removes old index entries
+  when path of object changes
+  (`#61 <https://github.com/zopefoundation/Products.ZCatalog/issues/61>`_)
+
 
 4.4 (2019-03-08)
 ----------------

src/Products/PluginIndexes/PathIndex/PathIndex.py

@@ -123,8 +123,10 @@ def index_object(self, docid, obj, threshold=100):
         if old_value == path:
             return 0
 
-        if old_value is None:
-            self._length.change(1)
+        if old_value:
+            self.unindex_object(docid)
+
+        self._length.change(1)
 
         for i in range(len(comps)):
             self.insertEntry(comps[i], docid, i)

src/Products/PluginIndexes/PathIndex/tests.py

@@ -367,6 +367,21 @@ def test__apply_index_QueryPathReturnedInResult(self):
         lst = list(res[0].keys())
         self.assertEqual(lst, [2, 3, 4])
 
+    def test__apply_index_when_path_changes(self):
+        index = self._makeOne()
+        doc = Dummy('/aa')
+        index.index_object(0, doc)
+        res = index._apply_index(dict(path='aa'))
+        self.assertEqual(list(res[0].keys()), [0])
+
+        doc.path = '/bb'
+        index.index_object(0, doc)
+        res = index._apply_index(dict(path='bb'))
+        self.assertEqual(list(res[0].keys()), [0])
+
+        res = index._apply_index(dict(path='aa'))
+        self.assertEqual(list(res[0].keys()), [])
+
     def test_numObjects_empty(self):
         index = self._makeOne()
         self.assertEqual(index.numObjects(), 0)