From: Raymond Hettinger <python@rcn.com>
Date: Thu, 31 Jan 2008 01:38:15 +0000 (+0000)
Subject: Fix defect in __ixor__ which would get the wrong
X-Git-Tag: v2.6a1~334
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e67420d72e26d976af2c8cd8603f2dfe158b6d24;p=python

Fix defect in __ixor__ which would get the wrong
answer if the input iterable had a duplicate element
(two calls to toggle() reverse each other).  Borrow
the correct code from sets.py.
---

diff --git a/Lib/_abcoll.py b/Lib/_abcoll.py
index e1e65106ce..75a8072528 100644
--- a/Lib/_abcoll.py
+++ b/Lib/_abcoll.py
@@ -266,16 +266,6 @@ class MutableSet(Set):
         self.discard(value)
         return value
 
-    def toggle(self, value):
-        """Return True if it was added, False if deleted."""
-        # XXX This implementation is not thread-safe
-        if value in self:
-            self.discard(value)
-            return False
-        else:
-            self.add(value)
-            return True
-
     def clear(self):
         """This is slow (creates N new iterators!) but effective."""
         try:
@@ -296,10 +286,13 @@ class MutableSet(Set):
         return self
 
     def __ixor__(self, it):
-        # This calls toggle(), so if that is overridded, we call the override
+        if not isinstance(it, Set):
+            it = self._from_iterable(it)
         for value in it:
-            self.toggle(it)
-        return self
+            if value in self:
+                self.discard(value)
+            else:
+                self.add(value)
 
     def __isub__(self, it):
         for value in it: