Merged revisions 72223 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r72223 | antoine.pitrou | 2009-05-02 23:13:23 +0200 (sam., 02 mai 2009) | 5 lines

  Isue #5084: unpickling now interns the attribute names of pickled objects,
  saving memory and avoiding growth in size of subsequent pickles. Proposal
  and original patch by Jake McGuire.
........

2 files changed, 23 insertions, 1 deletions

diff --git a/Lib/pickle.py b/Lib/pickle.py
index 409d4b2..b94b305 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -1195,7 +1195,15 @@ class _Unpickler:
         if isinstance(state, tuple) and len(state) == 2:
             state, slotstate = state
         if state:
-            inst.__dict__.update(state)
+            d = inst.__dict__
+            intern = sys.intern
+            try:
+                for k, v in state.items():
+                    d[intern(k)] = v
+            # keys in state don't have to be strings
+            # don't blow up, but don't go out of our way
+            except TypeError:
+                d.update(state)
         if slotstate:
             for k, v in slotstate.items():
                 setattr(inst, k, v)
diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index e3a929f..1585586 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -932,6 +932,20 @@ class AbstractPickleTests(unittest.TestCase):
                              "Failed protocol %d: %r != %r"
                              % (proto, obj, loaded))
 
+    def test_attribute_name_interning(self):
+        # Test that attribute names of pickled objects are interned when
+        # unpickling.
+        for proto in protocols:
+            x = C()
+            x.foo = 42
+            x.bar = "hello"
+            s = self.dumps(x, proto)
+            y = self.loads(s)
+            x_keys = sorted(x.__dict__)
+            y_keys = sorted(y.__dict__)
+            for x_key, y_key in zip(x_keys, y_keys):
+                self.assertIs(x_key, y_key)
+
 # Test classes for reduce_ex
 
 class REX_one(object):