Intermediate changes

commit_hash:134fe147a2593cd4e39895d6b77ac876aa724f8b

1 files changed, 8 insertions, 0 deletions

diff --git a/contrib/python/fonttools/fontTools/misc/visitor.py b/contrib/python/fonttools/fontTools/misc/visitor.py
index 6de432ef934..65f305632de 100644
--- a/contrib/python/fonttools/fontTools/misc/visitor.py
+++ b/contrib/python/fonttools/fontTools/misc/visitor.py
@@ -1,11 +1,19 @@
 """Generic visitor pattern implementation for Python objects."""
 
 import enum
+import weakref
 
 
 class Visitor(object):
     defaultStop = False
 
+    _visitors = {
+        # By default we skip visiting weak references to avoid recursion
+        # issues. Users can override this by registering a visit
+        # function for weakref.ProxyType.
+        weakref.ProxyType: {None: lambda self, obj, *args, **kwargs: False}
+    }
+
     @classmethod
     def _register(celf, clazzes_attrs):
         assert celf != Visitor, "Subclass Visitor instead."