Backport of _abccoll.py by Benjamin Arangueren, issue 1383.

With some changes of my own thrown in (e.g. backport of r58107).

Lib/_abcoll.py

@@ -0,0 +1,544 @@
+# Copyright 2007 Google, Inc. All Rights Reserved.
+# Licensed to PSF under a Contributor Agreement.
+
+"""Abstract Base Classes (ABCs) for collections, according to PEP 3119.
+
+DON'T USE THIS MODULE DIRECTLY!  The classes here should be imported
+via collections; they are defined here only to alleviate certain
+bootstrapping issues.  Unit tests are in test_collections.
+"""
+
+from abc import ABCMeta, abstractmethod
+
+__all__ = ["Hashable", "Iterable", "Iterator",
+           "Sized", "Container", "Callable",
+           "Set", "MutableSet",
+           "Mapping", "MutableMapping",
+           "MappingView", "KeysView", "ItemsView", "ValuesView",
+           "Sequence", "MutableSequence",
+           ]
+
+### ONE-TRICK PONIES ###
+
+class Hashable:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __hash__(self):
+        return 0
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Hashable:
+            for B in C.__mro__:
+                if "__hash__" in B.__dict__:
+                    if B.__dict__["__hash__"]:
+                        return True
+                    break
+        return NotImplemented
+
+
+class Iterable:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __iter__(self):
+        while False:
+            yield None
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Iterable:
+            if any("__iter__" in B.__dict__ for B in C.__mro__):
+                return True
+        return NotImplemented
+
+Iterable.register(str)
+
+
+class Iterator:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __next__(self):
+        raise StopIteration
+
+    def __iter__(self):
+        return self
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Iterator:
+            if any("next" in B.__dict__ for B in C.__mro__):
+                return True
+        return NotImplemented
+
+
+class Sized:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __len__(self):
+        return 0
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Sized:
+            if any("__len__" in B.__dict__ for B in C.__mro__):
+                return True
+        return NotImplemented
+
+
+class Container:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __contains__(self, x):
+        return False
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Container:
+            if any("__contains__" in B.__dict__ for B in C.__mro__):
+                return True
+        return NotImplemented
+
+
+class Callable:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __contains__(self, x):
+        return False
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Callable:
+            if any("__call__" in B.__dict__ for B in C.__mro__):
+                return True
+        return NotImplemented
+
+
+### SETS ###
+
+
+class Set:
+    __metaclass__ = ABCMeta
+
+    """A set is a finite, iterable container.
+
+    This class provides concrete generic implementations of all
+    methods except for __contains__, __iter__ and __len__.
+
+    To override the comparisons (presumably for speed, as the
+    semantics are fixed), all you have to do is redefine __le__ and
+    then the other operations will automatically follow suit.
+    """
+
+    @abstractmethod
+    def __contains__(self, value):
+        return False
+
+    @abstractmethod
+    def __iter__(self):
+        while False:
+            yield None
+
+    @abstractmethod
+    def __len__(self):
+        return 0
+
+    def __le__(self, other):
+        if not isinstance(other, Set):
+            return NotImplemented
+        if len(self) > len(other):
+            return False
+        for elem in self:
+            if elem not in other:
+                return False
+        return True
+
+    def __lt__(self, other):
+        if not isinstance(other, Set):
+            return NotImplemented
+        return len(self) < len(other) and self.__le__(other)
+
+    def __eq__(self, other):
+        if not isinstance(other, Set):
+            return NotImplemented
+        return len(self) == len(other) and self.__le__(other)
+
+    @classmethod
+    def _from_iterable(cls, it):
+        return frozenset(it)
+
+    def __and__(self, other):
+        if not isinstance(other, Iterable):
+            return NotImplemented
+        return self._from_iterable(value for value in other if value in self)
+
+    def __or__(self, other):
+        if not isinstance(other, Iterable):
+            return NotImplemented
+        return self._from_iterable(itertools.chain(self, other))
+
+    def __sub__(self, other):
+        if not isinstance(other, Set):
+            if not isinstance(other, Iterable):
+                return NotImplemented
+            other = self._from_iterable(other)
+        return self._from_iterable(value for value in self
+                                   if value not in other)
+
+    def __xor__(self, other):
+        if not isinstance(other, Set):
+            if not isinstance(other, Iterable):
+                return NotImplemented
+            other = self._from_iterable(other)
+        return (self - other) | (other - self)
+
+    def _hash(self):
+        """Compute the hash value of a set.
+
+        Note that we don't define __hash__: not all sets are hashable.
+        But if you define a hashable set type, its __hash__ should
+        call this function.
+
+        This must be compatible __eq__.
+
+        All sets ought to compare equal if they contain the same
+        elements, regardless of how they are implemented, and
+        regardless of the order of the elements; so there's not much
+        freedom for __eq__ or __hash__.  We match the algorithm used
+        by the built-in frozenset type.
+        """
+        MAX = sys.maxint
+        MASK = 2 * MAX + 1
+        n = len(self)
+        h = 1927868237 * (n + 1)
+        h &= MASK
+        for x in self:
+            hx = hash(x)
+            h ^= (hx ^ (hx << 16) ^ 89869747)  * 3644798167
+            h &= MASK
+        h = h * 69069 + 907133923
+        h &= MASK
+        if h > MAX:
+            h -= MASK + 1
+        if h == -1:
+            h = 590923713
+        return h
+
+Set.register(frozenset)
+
+
+class MutableSet(Set):
+
+    @abstractmethod
+    def add(self, value):
+        """Return True if it was added, False if already there."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def discard(self, value):
+        """Return True if it was deleted, False if not there."""
+        raise NotImplementedError
+
+    def pop(self):
+        """Return the popped value.  Raise KeyError if empty."""
+        it = iter(self)
+        try:
+            value = it.__next__()
+        except StopIteration:
+            raise KeyError
+        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:
+            while True:
+                self.pop()
+        except KeyError:
+            pass
+
+    def __ior__(self, it):
+        for value in it:
+            self.add(value)
+        return self
+
+    def __iand__(self, c):
+        for value in self:
+            if value not in c:
+                self.discard(value)
+        return self
+
+    def __ixor__(self, it):
+        # This calls toggle(), so if that is overridded, we call the override
+        for value in it:
+            self.toggle(it)
+        return self
+
+    def __isub__(self, it):
+        for value in it:
+            self.discard(value)
+        return self
+
+MutableSet.register(set)
+
+
+### MAPPINGS ###
+
+
+class Mapping:
+    __metaclass__ = ABCMeta
+
+    @abstractmethod
+    def __getitem__(self, key):
+        raise KeyError
+
+    def get(self, key, default=None):
+        try:
+            return self[key]
+        except KeyError:
+            return default
+
+    def __contains__(self, key):
+        try:
+            self[key]
+        except KeyError:
+            return False
+        else:
+            return True
+
+    @abstractmethod
+    def __len__(self):
+        return 0
+
+    @abstractmethod
+    def __iter__(self):
+        while False:
+            yield None
+
+    def keys(self):
+        return KeysView(self)
+
+    def items(self):
+        return ItemsView(self)
+
+    def values(self):
+        return ValuesView(self)
+
+
+class MappingView:
+    __metaclass__ = ABCMeta
+
+    def __init__(self, mapping):
+        self._mapping = mapping
+
+    def __len__(self):
+        return len(self._mapping)
+
+
+class KeysView(MappingView, Set):
+
+    def __contains__(self, key):
+        return key in self._mapping
+
+    def __iter__(self):
+        for key in self._mapping:
+            yield key
+
+KeysView.register(type({}.keys()))
+
+
+class ItemsView(MappingView, Set):
+
+    def __contains__(self, item):
+        key, value = item
+        try:
+            v = self._mapping[key]
+        except KeyError:
+            return False
+        else:
+            return v == value
+
+    def __iter__(self):
+        for key in self._mapping:
+            yield (key, self._mapping[key])
+
+ItemsView.register(type({}.items()))
+
+
+class ValuesView(MappingView):
+
+    def __contains__(self, value):
+        for key in self._mapping:
+            if value == self._mapping[key]:
+                return True
+        return False
+
+    def __iter__(self):
+        for key in self._mapping:
+            yield self._mapping[key]
+
+ValuesView.register(type({}.values()))
+
+
+class MutableMapping(Mapping):
+
+    @abstractmethod
+    def __setitem__(self, key, value):
+        raise KeyError
+
+    @abstractmethod
+    def __delitem__(self, key):
+        raise KeyError
+
+    __marker = object()
+
+    def pop(self, key, default=__marker):
+        try:
+            value = self[key]
+        except KeyError:
+            if default is self.__marker:
+                raise
+            return default
+        else:
+            del self[key]
+            return value
+
+    def popitem(self):
+        try:
+            key = next(iter(self))
+        except StopIteration:
+            raise KeyError
+        value = self[key]
+        del self[key]
+        return key, value
+
+    def clear(self):
+        try:
+            while True:
+                self.popitem()
+        except KeyError:
+            pass
+
+    def update(self, other=(), **kwds):
+        if isinstance(other, Mapping):
+            for key in other:
+                self[key] = other[key]
+        elif hasattr(other, "keys"):
+            for key in other.keys():
+                self[key] = other[key]
+        else:
+            for key, value in other:
+                self[key] = value
+        for key, value in kwds.items():
+            self[key] = value
+
+MutableMapping.register(dict)
+
+
+### SEQUENCES ###
+
+
+class Sequence:
+    __metaclass__ = ABCMeta
+
+    """All the operations on a read-only sequence.
+
+    Concrete subclasses must override __new__ or __init__,
+    __getitem__, and __len__.
+    """
+
+    @abstractmethod
+    def __getitem__(self, index):
+        raise IndexError
+
+    @abstractmethod
+    def __len__(self):
+        return 0
+
+    def __iter__(self):
+        i = 0
+        while True:
+            try:
+                v = self[i]
+            except IndexError:
+                break
+            yield v
+            i += 1
+
+    def __contains__(self, value):
+        for v in self:
+            if v == value:
+                return True
+        return False
+
+    def __reversed__(self):
+        for i in reversed(range(len(self))):
+            yield self[i]
+
+    def index(self, value):
+        for i, v in enumerate(self):
+            if v == value:
+                return i
+        raise ValueError
+
+    def count(self, value):
+        return sum(1 for v in self if v == value)
+
+Sequence.register(tuple)
+Sequence.register(basestring)
+Sequence.register(buffer)
+
+
+class MutableSequence(Sequence):
+
+    @abstractmethod
+    def __setitem__(self, index, value):
+        raise IndexError
+
+    @abstractmethod
+    def __delitem__(self, index):
+        raise IndexError
+
+    @abstractmethod
+    def insert(self, index, value):
+        raise IndexError
+
+    def append(self, value):
+        self.insert(len(self), value)
+
+    def reverse(self):
+        n = len(self)
+        for i in range(n//2):
+            self[i], self[n-i-1] = self[n-i-1], self[i]
+
+    def extend(self, values):
+        for v in values:
+            self.append(v)
+
+    def pop(self, index=-1):
+        v = self[index]
+        del self[index]
+        return v
+
+    def remove(self, value):
+        del self[self.index(value)]
+
+    def __iadd__(self, values):
+        self.extend(values)
+
+MutableSequence.register(list)

Lib/abc.py

@@ -69,7 +69,7 @@ class _Abstract(object):
         if (args or kwds) and cls.__init__ is object.__init__:
             raise TypeError("Can't pass arguments to __new__ "
                             "without overriding __init__")
-        return object.__new__(cls)
+        return super(_Abstract, cls).__new__(cls)
 
     @classmethod
     def __subclasshook__(cls, subclass):

Lib/collections.py

@@ -5,6 +5,12 @@ from operator import itemgetter as _itemgetter
 from keyword import iskeyword as _iskeyword
 import sys as _sys
 
+# For bootstrapping reasons, the collection ABCs are defined in _abcoll.py.
+# They should however be considered an integral part of collections.py.
+from _abcoll import *
+import _abcoll
+__all__ += _abcoll.__all__
+
 def namedtuple(typename, field_names, verbose=False):
     """Returns a new subclass of tuple with named fields.
 

Lib/test/mapping_tests.py

@@ -557,6 +557,8 @@ class TestHashMappingProtocol(TestMappingProtocol):
         class BadEq(object):
             def __eq__(self, other):
                 raise Exc()
+            def __hash__(self):
+                return 24
 
         d = self._empty_mapping()
         d[BadEq()] = 42
@@ -642,6 +644,8 @@ class TestHashMappingProtocol(TestMappingProtocol):
         class BadCmp(object):
             def __eq__(self, other):
                 raise Exc()
+            def __hash__(self):
+                return 42
 
         d1 = self._full_mapping({BadCmp(): 1})
         d2 = self._full_mapping({1: 1})

Lib/test/regrtest.py

@@ -648,7 +648,7 @@ def cleanup_test_droppings(testname, verbose):
 
 def dash_R(the_module, test, indirect_test, huntrleaks):
     # This code is hackish and inelegant, but it seems to do the job.
-    import copy_reg
+    import copy_reg, _abcoll
 
     if not hasattr(sys, 'gettotalrefcount'):
         raise Exception("Tracking reference leaks requires a debug build "
@@ -658,6 +658,12 @@ def dash_R(the_module, test, indirect_test, huntrleaks):
     fs = warnings.filters[:]
     ps = copy_reg.dispatch_table.copy()
     pic = sys.path_importer_cache.copy()
+    abcs = {}
+    for abc in [getattr(_abcoll, a) for a in _abcoll.__all__]:
+        for obj in abc.__subclasses__() + [abc]:
+            abcs[obj] = obj._abc_registry.copy()
+
+    print >> sys.stderr, abcs
 
     if indirect_test:
         def run_the_test():
@@ -671,12 +677,12 @@ def dash_R(the_module, test, indirect_test, huntrleaks):
     repcount = nwarmup + ntracked
     print >> sys.stderr, "beginning", repcount, "repetitions"
     print >> sys.stderr, ("1234567890"*(repcount//10 + 1))[:repcount]
-    dash_R_cleanup(fs, ps, pic)
+    dash_R_cleanup(fs, ps, pic, abcs)
     for i in range(repcount):
         rc = sys.gettotalrefcount()
         run_the_test()
         sys.stderr.write('.')
-        dash_R_cleanup(fs, ps, pic)
+        dash_R_cleanup(fs, ps, pic, abcs)
         if i >= nwarmup:
             deltas.append(sys.gettotalrefcount() - rc - 2)
     print >> sys.stderr
@@ -687,11 +693,11 @@ def dash_R(the_module, test, indirect_test, huntrleaks):
         print >> refrep, msg
         refrep.close()
 
-def dash_R_cleanup(fs, ps, pic):
+def dash_R_cleanup(fs, ps, pic, abcs):
     import gc, copy_reg
     import _strptime, linecache, dircache
     import urlparse, urllib, urllib2, mimetypes, doctest
-    import struct, filecmp
+    import struct, filecmp, _abcoll
     from distutils.dir_util import _path_created
 
     # Restore some original values.
@@ -701,6 +707,13 @@ def dash_R_cleanup(fs, ps, pic):
     sys.path_importer_cache.clear()
     sys.path_importer_cache.update(pic)
 
+    # Clear ABC registries, restoring previously saved ABC registries.
+    for abc in [getattr(_abcoll, a) for a in _abcoll.__all__]:
+        for obj in abc.__subclasses__() + [abc]:
+            obj._abc_registry = abcs.get(obj, {}).copy()
+            obj._abc_cache.clear()
+            obj._abc_negative_cache.clear()
+
     # Clear assorted module caches.
     _path_created.clear()
     re.purge()

Lib/test/test_abc.py

@@ -133,6 +133,20 @@ class TestABC(unittest.TestCase):
         self.failUnless(issubclass(MyInt, A))
         self.failUnless(isinstance(42, A))
 
+    def test_all_new_methods_are_called(self):
+        class A:
+            __metaclass__ = abc.ABCMeta
+        class B:
+            counter = 0
+            def __new__(cls):
+                B.counter += 1
+                return super(B, cls).__new__(cls)
+        class C(A, B):
+            pass
+        self.assertEqual(B.counter, 0)
+        C()
+        self.assertEqual(B.counter, 1)
+
 
 def test_main():
     test_support.run_unittest(TestABC)

Lib/test/test_collections.py

@@ -1,6 +1,12 @@
 import unittest
 from test import test_support
 from collections import namedtuple
+from collections import Hashable, Iterable, Iterator
+from collections import Sized, Container, Callable
+from collections import Set, MutableSet
+from collections import Mapping, MutableMapping
+from collections import Sequence, MutableSequence
+
 
 class TestNamedTuple(unittest.TestCase):
 
@@ -86,9 +92,187 @@ class TestNamedTuple(unittest.TestCase):
         Dot = namedtuple('Dot', 'd')
         self.assertEqual(Dot(1), (1,))
 
+
+class TestOneTrickPonyABCs(unittest.TestCase):
+
+    def test_Hashable(self):
+        # Check some non-hashables
+        non_samples = [list(), set(), dict()]
+        for x in non_samples:
+            self.failIf(isinstance(x, Hashable), repr(x))
+            self.failIf(issubclass(type(x), Hashable), repr(type(x)))
+        # Check some hashables
+        samples = [None,
+                   int(), float(), complex(),
+                   str(),
+                   tuple(), frozenset(),
+                   int, list, object, type,
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Hashable), repr(x))
+            self.failUnless(issubclass(type(x), Hashable), repr(type(x)))
+        self.assertRaises(TypeError, Hashable)
+        # Check direct subclassing
+        class H(Hashable):
+            def __hash__(self):
+                return super(H, self).__hash__()
+        self.assertEqual(hash(H()), 0)
+        self.failIf(issubclass(int, H))
+
+    def test_Iterable(self):
+        # Check some non-iterables
+        non_samples = [None, 42, 3.14, 1j]
+        for x in non_samples:
+            self.failIf(isinstance(x, Iterable), repr(x))
+            self.failIf(issubclass(type(x), Iterable), repr(type(x)))
+        # Check some iterables
+        samples = [str(),
+                   tuple(), list(), set(), frozenset(), dict(),
+                   dict().keys(), dict().items(), dict().values(),
+                   (lambda: (yield))(),
+                   (x for x in []),
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Iterable), repr(x))
+            self.failUnless(issubclass(type(x), Iterable), repr(type(x)))
+        # Check direct subclassing
+        class I(Iterable):
+            def __iter__(self):
+                return super(I, self).__iter__()
+        self.assertEqual(list(I()), [])
+        self.failIf(issubclass(str, I))
+
+    def test_Iterator(self):
+        non_samples = [None, 42, 3.14, 1j, "".encode('ascii'), "", (), [],
+            {}, set()]
+        for x in non_samples:
+            self.failIf(isinstance(x, Iterator), repr(x))
+            self.failIf(issubclass(type(x), Iterator), repr(type(x)))
+        samples = [iter(str()),
+                   iter(tuple()), iter(list()), iter(dict()),
+                   iter(set()), iter(frozenset()),
+                   iter(dict().keys()), iter(dict().items()),
+                   iter(dict().values()),
+                   (lambda: (yield))(),
+                   (x for x in []),
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Iterator), repr(x))
+            self.failUnless(issubclass(type(x), Iterator), repr(type(x)))
+
+    def test_Sized(self):
+        non_samples = [None, 42, 3.14, 1j,
+                       (lambda: (yield))(),
+                       (x for x in []),
+                       ]
+        for x in non_samples:
+            self.failIf(isinstance(x, Sized), repr(x))
+            self.failIf(issubclass(type(x), Sized), repr(type(x)))
+        samples = [str(),
+                   tuple(), list(), set(), frozenset(), dict(),
+                   dict().keys(), dict().items(), dict().values(),
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Sized), repr(x))
+            self.failUnless(issubclass(type(x), Sized), repr(type(x)))
+
+    def test_Container(self):
+        non_samples = [None, 42, 3.14, 1j,
+                       (lambda: (yield))(),
+                       (x for x in []),
+                       ]
+        for x in non_samples:
+            self.failIf(isinstance(x, Container), repr(x))
+            self.failIf(issubclass(type(x), Container), repr(type(x)))
+        samples = [str(),
+                   tuple(), list(), set(), frozenset(), dict(),
+                   dict().keys(), dict().items(),
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Container), repr(x))
+            self.failUnless(issubclass(type(x), Container), repr(type(x)))
+
+    def test_Callable(self):
+        non_samples = [None, 42, 3.14, 1j,
+                       "", "".encode('ascii'), (), [], {}, set(),
+                       (lambda: (yield))(),
+                       (x for x in []),
+                       ]
+        for x in non_samples:
+            self.failIf(isinstance(x, Callable), repr(x))
+            self.failIf(issubclass(type(x), Callable), repr(type(x)))
+        samples = [lambda: None,
+                   type, int, object,
+                   len,
+                   list.append, [].append,
+                   ]
+        for x in samples:
+            self.failUnless(isinstance(x, Callable), repr(x))
+            self.failUnless(issubclass(type(x), Callable), repr(type(x)))
+
+    def test_direct_subclassing(self):
+        for B in Hashable, Iterable, Iterator, Sized, Container, Callable:
+            class C(B):
+                pass
+            self.failUnless(issubclass(C, B))
+            self.failIf(issubclass(int, C))
+
+    def test_registration(self):
+        for B in Hashable, Iterable, Iterator, Sized, Container, Callable:
+            class C:
+                __metaclass__ = type
+                __hash__ = None  # Make sure it isn't hashable by default
+            self.failIf(issubclass(C, B), B.__name__)
+            B.register(C)
+            self.failUnless(issubclass(C, B))
+
+
+class TestCollectionABCs(unittest.TestCase):
+
+    # XXX For now, we only test some virtual inheritance properties.
+    # We should also test the proper behavior of the collection ABCs
+    # as real base classes or mix-in classes.
+
+    def test_Set(self):
+        for sample in [set, frozenset]:
+            self.failUnless(isinstance(sample(), Set))
+            self.failUnless(issubclass(sample, Set))
+
+    def test_MutableSet(self):
+        self.failUnless(isinstance(set(), MutableSet))
+        self.failUnless(issubclass(set, MutableSet))
+        self.failIf(isinstance(frozenset(), MutableSet))
+        self.failIf(issubclass(frozenset, MutableSet))
+
+    def test_Mapping(self):
+        for sample in [dict]:
+            self.failUnless(isinstance(sample(), Mapping))
+            self.failUnless(issubclass(sample, Mapping))
+
+    def test_MutableMapping(self):
+        for sample in [dict]:
+            self.failUnless(isinstance(sample(), MutableMapping))
+            self.failUnless(issubclass(sample, MutableMapping))
+
+    def test_Sequence(self):
+        for sample in [tuple, list, str]:
+            self.failUnless(isinstance(sample(), Sequence))
+            self.failUnless(issubclass(sample, Sequence))
+        self.failUnless(issubclass(basestring, Sequence))
+
+    def test_MutableSequence(self):
+        for sample in [tuple, str]:
+            self.failIf(isinstance(sample(), MutableSequence))
+            self.failIf(issubclass(sample, MutableSequence))
+        for sample in [list]:
+            self.failUnless(isinstance(sample(), MutableSequence))
+            self.failUnless(issubclass(sample, MutableSequence))
+        self.failIf(issubclass(basestring, MutableSequence))
+
+
 def test_main(verbose=None):
     import collections as CollectionsModule
-    test_classes = [TestNamedTuple]
+    test_classes = [TestNamedTuple, TestOneTrickPonyABCs, TestCollectionABCs]
     test_support.run_unittest(*test_classes)
     test_support.run_doctest(CollectionsModule, verbose)
 

Lib/test/test_dict.py

@@ -86,6 +86,8 @@ class DictTest(unittest.TestCase):
         class BadEq(object):
             def __eq__(self, other):
                 raise Exc()
+            def __hash__(self):
+                return 24
 
         d = {}
         d[BadEq()] = 42
@@ -397,6 +399,8 @@ class DictTest(unittest.TestCase):
         class BadCmp(object):
             def __eq__(self, other):
                 raise Exc()
+            def __hash__(self):
+                return 42
 
         d1 = {BadCmp(): 1}
         d2 = {1: 1}

Objects/dictobject.c

@@ -2127,13 +2127,6 @@ dict_init(PyObject *self, PyObject *args, PyObject *kwds)
 	return dict_update_common(self, args, kwds, "dict");
 }
 
-static long
-dict_nohash(PyObject *self)
-{
-	PyErr_SetString(PyExc_TypeError, "dict objects are unhashable");
-	return -1;
-}
-
 static PyObject *
 dict_iter(PyDictObject *dict)
 {
@@ -2165,7 +2158,7 @@ PyTypeObject PyDict_Type = {
 	0,					/* tp_as_number */
 	&dict_as_sequence,			/* tp_as_sequence */
 	&dict_as_mapping,			/* tp_as_mapping */
-	dict_nohash,				/* tp_hash */
+	0,					/* tp_hash */
 	0,					/* tp_call */
 	0,					/* tp_str */
 	PyObject_GenericGetAttr,		/* tp_getattro */

Objects/listobject.c

@@ -2393,13 +2393,6 @@ list_init(PyListObject *self, PyObject *args, PyObject *kw)
 	return 0;
 }
 
-static long
-list_nohash(PyObject *self)
-{
-	PyErr_SetString(PyExc_TypeError, "list objects are unhashable");
-	return -1;
-}
-
 static PyObject *list_iter(PyObject *seq);
 static PyObject *list_reversed(PyListObject* seq, PyObject* unused);
 
@@ -2694,7 +2687,7 @@ PyTypeObject PyList_Type = {
 	0,					/* tp_as_number */
 	&list_as_sequence,			/* tp_as_sequence */
 	&list_as_mapping,			/* tp_as_mapping */
-	list_nohash,				/* tp_hash */
+	0,					/* tp_hash */
 	0,					/* tp_call */
 	0,					/* tp_str */
 	PyObject_GenericGetAttr,		/* tp_getattro */
@@ -2959,4 +2952,3 @@ listreviter_len(listreviterobject *it)
 		return 0;
 	return len;
 }
-

Objects/object.c

@@ -1902,7 +1902,7 @@ static PyTypeObject PyNone_Type = {
 	0,		/*tp_as_number*/
 	0,		/*tp_as_sequence*/
 	0,		/*tp_as_mapping*/
-	0,		/*tp_hash */
+	(hashfunc)_Py_HashPointer, /*tp_hash */
 };
 
 PyObject _Py_NoneStruct = {

Objects/setobject.c

@@ -789,13 +789,6 @@ frozenset_hash(PyObject *self)
 	return hash;
 }
 
-static long
-set_nohash(PyObject *self)
-{
-	PyErr_SetString(PyExc_TypeError, "set objects are unhashable");
-	return -1;
-}
-
 /***** Set iterator type ***********************************************/
 
 typedef struct {
@@ -2012,7 +2005,7 @@ PyTypeObject PySet_Type = {
 	&set_as_number,			/* tp_as_number */
 	&set_as_sequence,		/* tp_as_sequence */
 	0,				/* tp_as_mapping */
-	set_nohash,			/* tp_hash */
+	0,				/* tp_hash */
 	0,				/* tp_call */
 	0,				/* tp_str */
 	PyObject_GenericGetAttr,	/* tp_getattro */

Objects/typeobject.c

@@ -2590,12 +2590,6 @@ object_str(PyObject *self)
 	return f(self);
 }
 
-static long
-object_hash(PyObject *self)
-{
-	return _Py_HashPointer(self);
-}
-
 static PyObject *
 object_get_class(PyObject *self, void *closure)
 {
@@ -3030,7 +3024,7 @@ PyTypeObject PyBaseObject_Type = {
 	0,					/* tp_as_number */
 	0,					/* tp_as_sequence */
 	0,					/* tp_as_mapping */
-	object_hash,				/* tp_hash */
+	(hashfunc)_Py_HashPointer,		/* tp_hash */
 	0,					/* tp_call */
 	object_str,				/* tp_str */
 	PyObject_GenericGetAttr,		/* tp_getattro */
@@ -3236,6 +3230,33 @@ inherit_special(PyTypeObject *type, PyTypeObject *base)
 		type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
 }
 
+/* Map rich comparison operators to their __xx__ namesakes */
+static char *name_op[] = {
+    "__lt__",
+    "__le__",
+    "__eq__",
+    "__ne__",
+    "__gt__",
+    "__ge__",
+    "__cmp__",
+ 	/* These are only for overrides_hash(): */
+    "__hash__",
+};
+
+static int
+overrides_hash(PyTypeObject *type)
+{
+	int i;
+	PyObject *dict = type->tp_dict;
+
+	assert(dict != NULL);
+	for (i = 0; i < 8; i++) {
+		if (PyDict_GetItemString(dict, name_op[i]) != NULL)
+			return 1;
+	}
+	return 0;
+}
+
 static void
 inherit_slots(PyTypeObject *type, PyTypeObject *base)
 {
@@ -3367,7 +3388,8 @@ inherit_slots(PyTypeObject *type, PyTypeObject *base)
 	if (type->tp_flags & base->tp_flags & Py_TPFLAGS_HAVE_RICHCOMPARE) {
 		if (type->tp_compare == NULL &&
 		    type->tp_richcompare == NULL &&
-		    type->tp_hash == NULL)
+		    type->tp_hash == NULL &&
+		    !overrides_hash(type))
 		{
 			type->tp_compare = base->tp_compare;
 			type->tp_richcompare = base->tp_richcompare;
@@ -3548,6 +3570,18 @@ PyType_Ready(PyTypeObject *type)
 		}
 	}
 
+	/* Hack for tp_hash and __hash__.
+	   If after all that, tp_hash is still NULL, and __hash__ is not in
+	   tp_dict, set tp_dict['__hash__'] equal to None.
+	   This signals that __hash__ is not inherited.
+	*/
+	if (type->tp_hash == NULL &&
+	    PyDict_GetItemString(type->tp_dict, "__hash__") == NULL &&
+	    PyDict_SetItemString(type->tp_dict, "__hash__", Py_None) < 0)
+	{
+		goto error;
+	}
+
 	/* Some more special stuff */
 	base = type->tp_base;
 	if (base != NULL) {
@@ -4937,16 +4971,6 @@ slot_tp_setattro(PyObject *self, PyObject *name, PyObject *value)
 	return 0;
 }
 
-/* Map rich comparison operators to their __xx__ namesakes */
-static char *name_op[] = {
-	"__lt__",
-	"__le__",
-	"__eq__",
-	"__ne__",
-	"__gt__",
-	"__ge__",
-};
-
 static PyObject *
 half_richcompare(PyObject *self, PyObject *other, int op)
 {