From a84f265c36d61c06c3f480f66e106a8864ab4fd4 Mon Sep 17 00:00:00 2001
From: Mark Dickinson <dickinsm@gmail.com>
Date: Thu, 12 Feb 2009 18:05:07 +0000
Subject: [PATCH] Merged revisions 68813,69546 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r68813 | raymond.hettinger | 2009-01-20 20:34:19 +0000 (Tue, 20 Jan 2009) | 3 lines

  Issue 4998:  __slots__ on Fractions was useless.
........
  r69546 | mark.dickinson | 2009-02-12 17:55:42 +0000 (Thu, 12 Feb 2009) | 2 lines

  Typo fix.
........
---
 Lib/numbers.py             | 9 +++++++++
 Lib/test/test_fractions.py | 5 +++++
 Misc/NEWS                  | 4 ++++
 3 files changed, 18 insertions(+)

diff --git a/Lib/numbers.py b/Lib/numbers.py
index fa59fd8e7de..540e7d59107 100644
--- a/Lib/numbers.py
+++ b/Lib/numbers.py
@@ -17,6 +17,7 @@ class Number(object):
     caring what kind, use isinstance(x, Number).
     """
     __metaclass__ = ABCMeta
+    __slots__ = ()
 
     # Concrete numeric types must provide their own hash implementation
     __hash__ = None
@@ -41,6 +42,8 @@ class Complex(Number):
     type as described below.
     """
 
+    __slots__ = ()
+
     @abstractmethod
     def __complex__(self):
         """Return a builtin complex instance. Called for complex(self)."""
@@ -172,6 +175,8 @@ class Real(Complex):
     Real also provides defaults for the derived operations.
     """
 
+    __slots__ = ()
+
     @abstractmethod
     def __float__(self):
         """Any Real can be converted to a native float object.
@@ -265,6 +270,8 @@ Real.register(float)
 class Rational(Real):
     """.numerator and .denominator should be in lowest terms."""
 
+    __slots__ = ()
+
     @abstractproperty
     def numerator(self):
         raise NotImplementedError
@@ -288,6 +295,8 @@ class Rational(Real):
 class Integral(Rational):
     """Integral adds a conversion to long and the bit-string operations."""
 
+    __slots__ = ()
+
     @abstractmethod
     def __long__(self):
         """long(self)"""
diff --git a/Lib/test/test_fractions.py b/Lib/test/test_fractions.py
index a6c3c32cb09..0509f92ccbc 100644
--- a/Lib/test/test_fractions.py
+++ b/Lib/test/test_fractions.py
@@ -394,6 +394,11 @@ class FractionTest(unittest.TestCase):
         self.assertEqual(id(r), id(copy(r)))
         self.assertEqual(id(r), id(deepcopy(r)))
 
+    def test_slots(self):
+        # Issue 4998
+        r = F(13, 7)
+        self.assertRaises(AttributeError, setattr, r, 'a', 10)
+
 def test_main():
     run_unittest(FractionTest, GcdTest)
 
diff --git a/Misc/NEWS b/Misc/NEWS
index 9176b6c807f..de3f6be4e26 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -80,6 +80,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #4998: The memory saving effect of __slots__ had been lost on Fractions
+  which inherited from numbers.py which did not have __slots__ defined.  The
+  numbers hierarchy now has its own __slots__ declarations.
+
 - Issue #5203: Fixed ctypes segfaults when passing a unicode string to a
   function without argtypes (only occurs if HAVE_USABLE_WCHAR_T is false).