Cache ancestors

astroid/nodes/scoped_nodes.py

@@ -43,6 +43,7 @@
 import io
 import itertools
 import typing
+from collections import OrderedDict
 from typing import List, Optional
 
 from astroid import bases
@@ -1962,6 +1963,9 @@ def my_meth(self, arg):
     # a dictionary of class instances attributes
     _astroid_fields = ("decorators", "bases", "keywords", "body")  # name
 
+    all_ancestors = {}
+    direct_ancestors = {}
+
     decorators = None
     """The decorators that are applied to this class.
 
@@ -2331,13 +2335,26 @@ def ancestors(self, recurs=True, context=None):
         :returns: The base classes
         :rtype: iterable(NodeNG)
         """
+        if recurs and context in self.all_ancestors:
+            yield from self.all_ancestors[context].keys()
+        elif not recurs and context in self.direct_ancestors:
+            yield from self.direct_ancestors[context].keys()
+
         # FIXME: should be possible to choose the resolution order
         # FIXME: inference make infinite loops possible here
-        yielded = {self}
+        yielded = OrderedDict()
+        yielded[self] = None
         if context is None:
             context = contextmod.InferenceContext()
         if not self.bases and self.qname() != "builtins.object":
-            yield builtin_lookup("object")[1][0]
+            result = builtin_lookup("object")[1][0]
+            yielded[result] = None
+            del yielded[self]
+            if recurs:
+                self.all_ancestors[context] = yielded
+            else:
+                self.direct_ancestors[context] = yielded
+            yield result
             return
 
         for stmt in self.bases:
@@ -2352,7 +2369,7 @@ def ancestors(self, recurs=True, context=None):
                         if not baseobj.hide:
                             if baseobj in yielded:
                                 continue
-                            yielded.add(baseobj)
+                            yielded[baseobj] = None
                             yield baseobj
                         if not recurs:
                             continue
@@ -2362,11 +2379,17 @@ def ancestors(self, recurs=True, context=None):
                                 break
                             if grandpa in yielded:
                                 continue
-                            yielded.add(grandpa)
+                            yielded[grandpa] = None
                             yield grandpa
                 except InferenceError:
                     continue
 
+        del yielded[self]
+        if recurs:
+            self.all_ancestors[context] = yielded
+        else:
+            self.direct_ancestors[context] = yielded
+
     def local_attr_ancestors(self, name, context=None):
         """Iterate over the parents that define the given name.
 

tests/unittest_scoped_nodes.py

@@ -1040,7 +1040,7 @@ class Past(Present):
         astroid = builder.parse(data)
         past = astroid["Past"]
         attr = past.getattr("attr")
-        self.assertEqual(len(attr), 1)
+        self.assertEqual(len(attr), 1, attr)
         attr1 = attr[0]
         self.assertIsInstance(attr1, nodes.AssignName)
         self.assertEqual(attr1.name, "attr")