Mailman 3 November 2014 - Python-checkins

cpython (3.4): Issue #22609: Revert changes in UserDict. They conflicted with existing tests.
by serhiy.storchaka 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/cd1ead4feddf changeset: 93621:cd1ead4feddf branch: 3.4 parent: 93619:816c15fe5812 user: Serhiy Storchaka <storchaka(a)gmail.com> date: Thu Nov 27 17:45:44 2014 +0200 summary: Issue #22609: Revert changes in UserDict. They conflicted with existing tests. files: Lib/collections/__init__.py | 9 +-------- Lib/test/test_collections.py | 21 +-------------------- 2 files changed, 2 insertions(+), 28 deletions(-) diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py --- a/Lib/collections/__init__.py +++ b/Lib/collections/__init__.py @@ -893,14 +893,7 @@ class UserDict(MutableMapping): # Start by filling-out the abstract methods - def __init__(*args, **kwargs): - if not args: - raise TypeError("descriptor '__init__' of 'UserDict' object " - "needs an argument") - self, *args = args - if len(args) > 1: - raise TypeError('expected at most 1 arguments, got %d' % len(args)) - dict = args[0] if args else None + def __init__(self, dict=None, **kwargs): self.data = {} if dict is not None: self.update(dict) diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -1571,24 +1571,6 @@ d = self._empty_mapping() self.assertRaises(KeyError, d.popitem) -class TestUserDict(unittest.TestCase): - - def test_init(self): - self.assertEqual(list(UserDict(self=42).items()), [('self', 42)]) - self.assertEqual(list(UserDict(dict=42).items()), [('dict', 42)]) - self.assertEqual(list(UserDict(dict=None).items()), [('dict', None)]) - self.assertRaises(TypeError, UserDict, 42) - self.assertRaises(TypeError, UserDict, (), ()) - self.assertRaises(TypeError, UserDict.__init__) - - def test_update(self): - d = UserDict() - d.update(self=42) - self.assertEqual(list(d.items()), [('self', 42)]) - self.assertRaises(TypeError, UserDict().update, 42) - self.assertRaises(TypeError, UserDict().update, {}, {}) - self.assertRaises(TypeError, UserDict.update) - ################################################################################ ### Run tests @@ -1600,8 +1582,7 @@ NamedTupleDocs = doctest.DocTestSuite(module=collections) test_classes = [TestNamedTuple, NamedTupleDocs, TestOneTrickPonyABCs, TestCollectionABCs, TestCounter, TestChainMap, - TestOrderedDict, GeneralMappingTests, SubclassMappingTests, - TestUserDict,] + TestOrderedDict, GeneralMappingTests, SubclassMappingTests] support.run_unittest(*test_classes) support.run_doctest(collections, verbose) -- Repository URL: https://hg.python.org/cpython

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cpython (merge 3.4 -> default): Issue #22609: Constructors and update methods of mapping classes in the
by serhiy.storchaka 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/88ab046fdd8a changeset: 93620:88ab046fdd8a parent: 93617:1c97f373fe49 parent: 93619:816c15fe5812 user: Serhiy Storchaka <storchaka(a)gmail.com> date: Thu Nov 27 16:35:26 2014 +0200 summary: Issue #22609: Constructors and update methods of mapping classes in the collections module now accept the self keyword argument. files: Lib/_collections_abc.py | 35 ++++++------ Lib/collections/__init__.py | 47 ++++++++++++++--- Lib/test/test_collections.py | 64 ++++++++++++++++++++++- Misc/NEWS | 3 + 4 files changed, 121 insertions(+), 28 deletions(-) diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py --- a/Lib/_collections_abc.py +++ b/Lib/_collections_abc.py @@ -592,23 +592,24 @@ If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v ''' - if len(args) > 2: - raise TypeError("update() takes at most 2 positional " - "arguments ({} given)".format(len(args))) - elif not args: - raise TypeError("update() takes at least 1 argument (0 given)") - self = args[0] - other = args[1] if len(args) >= 2 else () - - 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 + if not args: + raise TypeError("descriptor 'update' of 'MutableMapping' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('update expected at most 1 arguments, got %d' % + len(args)) + if args: + other = args[0] + 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 diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py --- a/Lib/collections/__init__.py +++ b/Lib/collections/__init__.py @@ -55,12 +55,16 @@ # Individual links are kept alive by the hard reference in self.__map. # Those hard references disappear when a key is deleted from an OrderedDict. - def __init__(self, *args, **kwds): + def __init__(*args, **kwds): '''Initialize an ordered dictionary. The signature is the same as regular dictionaries, but keyword arguments are not recommended because their insertion order is arbitrary. ''' + if not args: + raise TypeError("descriptor '__init__' of 'OrderedDict' object " + "needs an argument") + self, *args = args if len(args) > 1: raise TypeError('expected at most 1 arguments, got %d' % len(args)) try: @@ -479,7 +483,7 @@ # http://code.activestate.com/recipes/259174/ # Knuth, TAOCP Vol. II section 4.6.3 - def __init__(self, iterable=None, **kwds): + def __init__(*args, **kwds): '''Create a new, empty Counter object. And if given, count elements from an input iterable. Or, initialize the count from another mapping of elements to their counts. @@ -490,8 +494,14 @@ >>> c = Counter(a=4, b=2) # a new counter from keyword args ''' - super().__init__() - self.update(iterable, **kwds) + if not args: + raise TypeError("descriptor '__init__' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + super(Counter, self).__init__() + self.update(*args, **kwds) def __missing__(self, key): 'The count of elements not in the Counter is zero.' @@ -542,7 +552,7 @@ raise NotImplementedError( 'Counter.fromkeys() is undefined. Use Counter(iterable) instead.') - def update(self, iterable=None, **kwds): + def update(*args, **kwds): '''Like dict.update() but add counts instead of replacing them. Source can be an iterable, a dictionary, or another Counter instance. @@ -562,6 +572,13 @@ # contexts. Instead, we implement straight-addition. Both the inputs # and outputs are allowed to contain zero and negative counts. + if not args: + raise TypeError("descriptor 'update' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + iterable = args[0] if args else None if iterable is not None: if isinstance(iterable, Mapping): if self: @@ -569,13 +586,13 @@ for elem, count in iterable.items(): self[elem] = count + self_get(elem, 0) else: - super().update(iterable) # fast path when counter is empty + super(Counter, self).update(iterable) # fast path when counter is empty else: _count_elements(self, iterable) if kwds: self.update(kwds) - def subtract(self, iterable=None, **kwds): + def subtract(*args, **kwds): '''Like dict.update() but subtracts counts instead of replacing them. Counts can be reduced below zero. Both the inputs and outputs are allowed to contain zero and negative counts. @@ -591,6 +608,13 @@ -1 ''' + if not args: + raise TypeError("descriptor 'subtract' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + iterable = args[0] if args else None if iterable is not None: self_get = self.get if isinstance(iterable, Mapping): @@ -898,7 +922,14 @@ class UserDict(MutableMapping): # Start by filling-out the abstract methods - def __init__(self, dict=None, **kwargs): + def __init__(*args, **kwargs): + if not args: + raise TypeError("descriptor '__init__' of 'UserDict' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + dict = args[0] if args else None self.data = {} if dict is not None: self.update(dict) diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -1137,6 +1137,28 @@ self.assertEqual(c.setdefault('e', 5), 5) self.assertEqual(c['e'], 5) + def test_init(self): + self.assertEqual(list(Counter(self=42).items()), [('self', 42)]) + self.assertEqual(list(Counter(iterable=42).items()), [('iterable', 42)]) + self.assertEqual(list(Counter(iterable=None).items()), [('iterable', None)]) + self.assertRaises(TypeError, Counter, 42) + self.assertRaises(TypeError, Counter, (), ()) + self.assertRaises(TypeError, Counter.__init__) + + def test_update(self): + c = Counter() + c.update(self=42) + self.assertEqual(list(c.items()), [('self', 42)]) + c = Counter() + c.update(iterable=42) + self.assertEqual(list(c.items()), [('iterable', 42)]) + c = Counter() + c.update(iterable=None) + self.assertEqual(list(c.items()), [('iterable', None)]) + self.assertRaises(TypeError, Counter().update, 42) + self.assertRaises(TypeError, Counter().update, {}, {}) + self.assertRaises(TypeError, Counter.update) + def test_copying(self): # Check that counters are copyable, deepcopyable, picklable, and #have a repr/eval round-trip @@ -1258,6 +1280,16 @@ c.subtract('aaaabbcce') self.assertEqual(c, Counter(a=-1, b=0, c=-1, d=1, e=-1)) + c = Counter() + c.subtract(self=42) + self.assertEqual(list(c.items()), [('self', -42)]) + c = Counter() + c.subtract(iterable=42) + self.assertEqual(list(c.items()), [('iterable', -42)]) + self.assertRaises(TypeError, Counter().subtract, 42) + self.assertRaises(TypeError, Counter().subtract, {}, {}) + self.assertRaises(TypeError, Counter.subtract) + def test_unary(self): c = Counter(a=-5, b=0, c=5, d=10, e=15,g=40) self.assertEqual(dict(+c), dict(c=5, d=10, e=15, g=40)) @@ -1308,8 +1340,11 @@ c=3, e=5).items()), pairs) # mixed input # make sure no positional args conflict with possible kwdargs - self.assertEqual(inspect.getargspec(OrderedDict.__dict__['__init__']).args, - ['self']) + self.assertEqual(list(OrderedDict(self=42).items()), [('self', 42)]) + self.assertEqual(list(OrderedDict(other=42).items()), [('other', 42)]) + self.assertRaises(TypeError, OrderedDict, 42) + self.assertRaises(TypeError, OrderedDict, (), ()) + self.assertRaises(TypeError, OrderedDict.__init__) # Make sure that direct calls to __init__ do not clear previous contents d = OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 44), ('e', 55)]) @@ -1354,6 +1389,10 @@ self.assertEqual(list(d.items()), [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5), ('f', 6), ('g', 7)]) + self.assertRaises(TypeError, OrderedDict().update, 42) + self.assertRaises(TypeError, OrderedDict().update, (), ()) + self.assertRaises(TypeError, OrderedDict.update) + def test_abc(self): self.assertIsInstance(OrderedDict(), MutableMapping) self.assertTrue(issubclass(OrderedDict, MutableMapping)) @@ -1600,6 +1639,24 @@ d = self._empty_mapping() self.assertRaises(KeyError, d.popitem) +class TestUserDict(unittest.TestCase): + + def test_init(self): + self.assertEqual(list(UserDict(self=42).items()), [('self', 42)]) + self.assertEqual(list(UserDict(dict=42).items()), [('dict', 42)]) + self.assertEqual(list(UserDict(dict=None).items()), [('dict', None)]) + self.assertRaises(TypeError, UserDict, 42) + self.assertRaises(TypeError, UserDict, (), ()) + self.assertRaises(TypeError, UserDict.__init__) + + def test_update(self): + d = UserDict() + d.update(self=42) + self.assertEqual(list(d.items()), [('self', 42)]) + self.assertRaises(TypeError, UserDict().update, 42) + self.assertRaises(TypeError, UserDict().update, {}, {}) + self.assertRaises(TypeError, UserDict.update) + ################################################################################ ### Run tests @@ -1611,7 +1668,8 @@ NamedTupleDocs = doctest.DocTestSuite(module=collections) test_classes = [TestNamedTuple, NamedTupleDocs, TestOneTrickPonyABCs, TestCollectionABCs, TestCounter, TestChainMap, - TestOrderedDict, GeneralMappingTests, SubclassMappingTests] + TestOrderedDict, GeneralMappingTests, SubclassMappingTests, + TestUserDict,] support.run_unittest(*test_classes) support.run_doctest(collections, verbose) diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -191,6 +191,9 @@ Library ------- +- Issue #22609: Constructors and update methods of mapping classes in the + collections module now accept the self keyword argument. + - Issue #22940: Add readline.append_history_file. - Issue #19676: Added the "namereplace" error handler. -- Repository URL: https://hg.python.org/cpython

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cpython (3.4): Issue #22609: Constructors and update methods of mapping classes in the
by serhiy.storchaka 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/816c15fe5812 changeset: 93619:816c15fe5812 branch: 3.4 parent: 93616:589c65dc528c user: Serhiy Storchaka <storchaka(a)gmail.com> date: Thu Nov 27 16:25:51 2014 +0200 summary: Issue #22609: Constructors and update methods of mapping classes in the collections module now accept the self keyword argument. files: Lib/_collections_abc.py | 35 ++++++------ Lib/collections/__init__.py | 47 ++++++++++++++--- Lib/test/test_collections.py | 64 ++++++++++++++++++++++- Misc/NEWS | 3 + 4 files changed, 121 insertions(+), 28 deletions(-) diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py --- a/Lib/_collections_abc.py +++ b/Lib/_collections_abc.py @@ -584,23 +584,24 @@ If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v ''' - if len(args) > 2: - raise TypeError("update() takes at most 2 positional " - "arguments ({} given)".format(len(args))) - elif not args: - raise TypeError("update() takes at least 1 argument (0 given)") - self = args[0] - other = args[1] if len(args) >= 2 else () - - 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 + if not args: + raise TypeError("descriptor 'update' of 'MutableMapping' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('update expected at most 1 arguments, got %d' % + len(args)) + if args: + other = args[0] + 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 diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py --- a/Lib/collections/__init__.py +++ b/Lib/collections/__init__.py @@ -38,12 +38,16 @@ # Individual links are kept alive by the hard reference in self.__map. # Those hard references disappear when a key is deleted from an OrderedDict. - def __init__(self, *args, **kwds): + def __init__(*args, **kwds): '''Initialize an ordered dictionary. The signature is the same as regular dictionaries, but keyword arguments are not recommended because their insertion order is arbitrary. ''' + if not args: + raise TypeError("descriptor '__init__' of 'OrderedDict' object " + "needs an argument") + self, *args = args if len(args) > 1: raise TypeError('expected at most 1 arguments, got %d' % len(args)) try: @@ -450,7 +454,7 @@ # http://code.activestate.com/recipes/259174/ # Knuth, TAOCP Vol. II section 4.6.3 - def __init__(self, iterable=None, **kwds): + def __init__(*args, **kwds): '''Create a new, empty Counter object. And if given, count elements from an input iterable. Or, initialize the count from another mapping of elements to their counts. @@ -461,8 +465,14 @@ >>> c = Counter(a=4, b=2) # a new counter from keyword args ''' - super().__init__() - self.update(iterable, **kwds) + if not args: + raise TypeError("descriptor '__init__' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + super(Counter, self).__init__() + self.update(*args, **kwds) def __missing__(self, key): 'The count of elements not in the Counter is zero.' @@ -513,7 +523,7 @@ raise NotImplementedError( 'Counter.fromkeys() is undefined. Use Counter(iterable) instead.') - def update(self, iterable=None, **kwds): + def update(*args, **kwds): '''Like dict.update() but add counts instead of replacing them. Source can be an iterable, a dictionary, or another Counter instance. @@ -533,6 +543,13 @@ # contexts. Instead, we implement straight-addition. Both the inputs # and outputs are allowed to contain zero and negative counts. + if not args: + raise TypeError("descriptor 'update' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + iterable = args[0] if args else None if iterable is not None: if isinstance(iterable, Mapping): if self: @@ -540,13 +557,13 @@ for elem, count in iterable.items(): self[elem] = count + self_get(elem, 0) else: - super().update(iterable) # fast path when counter is empty + super(Counter, self).update(iterable) # fast path when counter is empty else: _count_elements(self, iterable) if kwds: self.update(kwds) - def subtract(self, iterable=None, **kwds): + def subtract(*args, **kwds): '''Like dict.update() but subtracts counts instead of replacing them. Counts can be reduced below zero. Both the inputs and outputs are allowed to contain zero and negative counts. @@ -562,6 +579,13 @@ -1 ''' + if not args: + raise TypeError("descriptor 'subtract' of 'Counter' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + iterable = args[0] if args else None if iterable is not None: self_get = self.get if isinstance(iterable, Mapping): @@ -869,7 +893,14 @@ class UserDict(MutableMapping): # Start by filling-out the abstract methods - def __init__(self, dict=None, **kwargs): + def __init__(*args, **kwargs): + if not args: + raise TypeError("descriptor '__init__' of 'UserDict' object " + "needs an argument") + self, *args = args + if len(args) > 1: + raise TypeError('expected at most 1 arguments, got %d' % len(args)) + dict = args[0] if args else None self.data = {} if dict is not None: self.update(dict) diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -1084,6 +1084,28 @@ self.assertEqual(c.setdefault('e', 5), 5) self.assertEqual(c['e'], 5) + def test_init(self): + self.assertEqual(list(Counter(self=42).items()), [('self', 42)]) + self.assertEqual(list(Counter(iterable=42).items()), [('iterable', 42)]) + self.assertEqual(list(Counter(iterable=None).items()), [('iterable', None)]) + self.assertRaises(TypeError, Counter, 42) + self.assertRaises(TypeError, Counter, (), ()) + self.assertRaises(TypeError, Counter.__init__) + + def test_update(self): + c = Counter() + c.update(self=42) + self.assertEqual(list(c.items()), [('self', 42)]) + c = Counter() + c.update(iterable=42) + self.assertEqual(list(c.items()), [('iterable', 42)]) + c = Counter() + c.update(iterable=None) + self.assertEqual(list(c.items()), [('iterable', None)]) + self.assertRaises(TypeError, Counter().update, 42) + self.assertRaises(TypeError, Counter().update, {}, {}) + self.assertRaises(TypeError, Counter.update) + def test_copying(self): # Check that counters are copyable, deepcopyable, picklable, and #have a repr/eval round-trip @@ -1205,6 +1227,16 @@ c.subtract('aaaabbcce') self.assertEqual(c, Counter(a=-1, b=0, c=-1, d=1, e=-1)) + c = Counter() + c.subtract(self=42) + self.assertEqual(list(c.items()), [('self', -42)]) + c = Counter() + c.subtract(iterable=42) + self.assertEqual(list(c.items()), [('iterable', -42)]) + self.assertRaises(TypeError, Counter().subtract, 42) + self.assertRaises(TypeError, Counter().subtract, {}, {}) + self.assertRaises(TypeError, Counter.subtract) + def test_unary(self): c = Counter(a=-5, b=0, c=5, d=10, e=15,g=40) self.assertEqual(dict(+c), dict(c=5, d=10, e=15, g=40)) @@ -1255,8 +1287,11 @@ c=3, e=5).items()), pairs) # mixed input # make sure no positional args conflict with possible kwdargs - self.assertEqual(inspect.getargspec(OrderedDict.__dict__['__init__']).args, - ['self']) + self.assertEqual(list(OrderedDict(self=42).items()), [('self', 42)]) + self.assertEqual(list(OrderedDict(other=42).items()), [('other', 42)]) + self.assertRaises(TypeError, OrderedDict, 42) + self.assertRaises(TypeError, OrderedDict, (), ()) + self.assertRaises(TypeError, OrderedDict.__init__) # Make sure that direct calls to __init__ do not clear previous contents d = OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 44), ('e', 55)]) @@ -1301,6 +1336,10 @@ self.assertEqual(list(d.items()), [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5), ('f', 6), ('g', 7)]) + self.assertRaises(TypeError, OrderedDict().update, 42) + self.assertRaises(TypeError, OrderedDict().update, (), ()) + self.assertRaises(TypeError, OrderedDict.update) + def test_abc(self): self.assertIsInstance(OrderedDict(), MutableMapping) self.assertTrue(issubclass(OrderedDict, MutableMapping)) @@ -1532,6 +1571,24 @@ d = self._empty_mapping() self.assertRaises(KeyError, d.popitem) +class TestUserDict(unittest.TestCase): + + def test_init(self): + self.assertEqual(list(UserDict(self=42).items()), [('self', 42)]) + self.assertEqual(list(UserDict(dict=42).items()), [('dict', 42)]) + self.assertEqual(list(UserDict(dict=None).items()), [('dict', None)]) + self.assertRaises(TypeError, UserDict, 42) + self.assertRaises(TypeError, UserDict, (), ()) + self.assertRaises(TypeError, UserDict.__init__) + + def test_update(self): + d = UserDict() + d.update(self=42) + self.assertEqual(list(d.items()), [('self', 42)]) + self.assertRaises(TypeError, UserDict().update, 42) + self.assertRaises(TypeError, UserDict().update, {}, {}) + self.assertRaises(TypeError, UserDict.update) + ################################################################################ ### Run tests @@ -1543,7 +1600,8 @@ NamedTupleDocs = doctest.DocTestSuite(module=collections) test_classes = [TestNamedTuple, NamedTupleDocs, TestOneTrickPonyABCs, TestCollectionABCs, TestCounter, TestChainMap, - TestOrderedDict, GeneralMappingTests, SubclassMappingTests] + TestOrderedDict, GeneralMappingTests, SubclassMappingTests, + TestUserDict,] support.run_unittest(*test_classes) support.run_doctest(collections, verbose) diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -36,6 +36,9 @@ Library ------- +- Issue #22609: Constructors and update methods of mapping classes in the + collections module now accept the self keyword argument. + - Issue #22788: Add *context* parameter to logging.handlers.HTTPHandler. - Issue #22921: Allow SSLContext to take the *hostname* parameter even if -- Repository URL: https://hg.python.org/cpython

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Daily reference leaks (c8bcede1b37a): sum=3
by solipsis＠pitrou.net 27 Nov '14

27 Nov '14

results for c8bcede1b37a on branch "default" -------------------------------------------- test_functools leaked [0, 0, 3] memory blocks, sum=3 Command line was: ['./python', '-m', 'test.regrtest', '-uall', '-R', '3:3:/home/antoine/cpython/refleaks/reflogNSqzH_', '-x']

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peps: New section with contextlib example (Isaac Schwabacher).
by guido.van.rossum 27 Nov '14

27 Nov '14

https://hg.python.org/peps/rev/bb0f11810471 changeset: 5623:bb0f11810471 user: Guido van Rossum <guido(a)python.org> date: Wed Nov 26 22:07:29 2014 -0800 summary: New section with contextlib example (Isaac Schwabacher). Other additions by Chris, including renumbered references. files: pep-0479.txt | 105 ++++++++++++++++++++++++++++++-------- 1 files changed, 82 insertions(+), 23 deletions(-) diff --git a/pep-0479.txt b/pep-0479.txt --- a/pep-0479.txt +++ b/pep-0479.txt @@ -37,12 +37,39 @@ generator to terminate silently. (When another exception is raised, a traceback is printed pinpointing the cause of the problem.) -The proposal also clears up the confusion about how to terminate a -generator: the proper way is ``return``, not ``raise StopIteration``. +This is particularly pernicious in combination with the ``yield from`` +construct of PEP 380 [1]_, as it breaks the abstraction that a +subgenerator may be factored out of a generator. That PEP notes this +limitation, but notes that "use cases for these [are] rare to non- +existent". Unfortunately while intentional use is rare, it is easy to +stumble on these cases by accident:: -Finally, the proposal reduces the difference between list + @contextlib.contextmanager + def transaction(): + begin() + try: + yield from do_it() + except: + rollback() + raise + else: + commit() + + def do_it(): + initial_preparations() + yield + finishing_touches() + +Here factoring out ``do_it`` into a subgenerator has introduced a +subtle bug: if the wrapped block raises ``StopIteration``, under the +current behavior ``do_it`` will fail but report success by returning +normally, causing the failed transaction to be committed! Similarly +problematic behavior occurs when an ``asyncio`` coroutine raises +``StopIteration``, causing it to terminate silently. + +Additionally, the proposal reduces the difference between list comprehensions and generator expressions, preventing surprises such as -the one that started this discussion [1]_. Henceforth, the following +the one that started this discussion [2]_. Henceforth, the following statements will produce the same result if either produces a result at all:: @@ -56,6 +83,10 @@ will raise an exception at this point (albeit ``RuntimeError`` in the first case and ``StopIteration`` in the second). +Finally, the proposal also clears up the confusion about how to +terminate a generator: the proper way is ``return``, not +``raise StopIteration``. + Background information ====================== @@ -77,7 +108,7 @@ If a ``StopIteration`` is about to bubble out of a generator frame, it is replaced with ``RuntimeError``, which causes the ``next()`` call (which invoked the generator) to fail, passing that exception out. -From then on it's just like any old exception. [3]_ +From then on it's just like any old exception. [4]_ This affects the third outcome listed above, without altering any other effects. Furthermore, it only affects this outcome when the @@ -119,10 +150,10 @@ This change will affect existing code that depends on ``StopIteration`` bubbling up. The pure Python reference -implementation of ``groupby`` [2]_ currently has comments "Exit on +implementation of ``groupby`` [3]_ currently has comments "Exit on ``StopIteration``" where it is expected that the exception will propagate and then be handled. This will be unusual, but not unknown, -and such constructs will fail. Other examples abound, e.g. [5]_, [6]_. +and such constructs will fail. Other examples abound, e.g. [6]_, [7]_. (Nick Coghlan comments: """If you wanted to factor out a helper function that terminated the generator you'd have to do "return @@ -235,6 +266,31 @@ to find the end marker in the inner loop, which will now raise ``RuntimeError``). +This effect of ``StopIteration`` has been used to cut a generator +expression short, creating a form of ``takewhile``:: + + def stop(): + raise StopIteration + print(list(x for x in range(10) if x < 5 or stop())) + # prints [0, 1, 2, 3, 4] + +Under the current proposal, this form of non-local flow control is +not supported, and would have to be rewritten in statement form:: + + def gen(): + for x in range(10): + if x >= 5: return + yield x + print(list(gen())) + # prints [0, 1, 2, 3, 4] + +While this is a small loss of functionality, it is functionality that +often comes at the cost of readability, and just as ``lambda`` has +restrictions compared to ``def``, so does a generator expression have +restrictions compared to a generator function. In many cases, the +transformation to full generator function will be trivially easy, and +may improve structural clarity. + Explanation of generators, iterators, and StopIteration ======================================================= @@ -330,7 +386,7 @@ return statement. The inspiration for this alternative proposal was Nick's observation -[7]_ that if an ``asyncio`` coroutine [8]_ accidentally raises +[8]_ that if an ``asyncio`` coroutine [9]_ accidentally raises ``StopIteration``, it currently terminates silently, which may present a hard-to-debug mystery to the developer. The main proposal turns such accidents into clearly distinguishable ``RuntimeError`` exceptions, @@ -367,7 +423,7 @@ Converting the exception inside next() -------------------------------------- -Mark Shannon suggested [11]_ that the problem could be solved in +Mark Shannon suggested [12]_ that the problem could be solved in ``next()`` rather than at the boundary of generator functions. By having ``next()`` catch ``StopIteration`` and raise instead ``ValueError``, all unexpected ``StopIteration`` bubbling would be @@ -384,11 +440,11 @@ ========= Unofficial and apocryphal statistics suggest that this is seldom, if -ever, a problem. [4]_ Code does exist which relies on the current -behaviour (e.g. [2]_, [5]_, [6]_), and there is the concern that this +ever, a problem. [5]_ Code does exist which relies on the current +behaviour (e.g. [3]_, [6]_, [7]_), and there is the concern that this would be unnecessary code churn to achieve little or no gain. -Steven D'Aprano started an informal survey on comp.lang.python [9]_; +Steven D'Aprano started an informal survey on comp.lang.python [10]_; at the time of writing only two responses have been received: one was in favor of changing list comprehensions to match generator expressions (!), the other was in favor of this PEP's main proposal. @@ -411,37 +467,40 @@ References ========== -.. [1] Initial mailing list comment +.. [1] PEP 380 - Syntax for Delegating to a Subgenerator + (https://www.python.org/dev/peps/pep-0380) + +.. [2] Initial mailing list comment (https://mail.python.org/pipermail/python-ideas/2014-November/029906.html) -.. [2] Pure Python implementation of groupby +.. [3] Pure Python implementation of groupby (https://docs.python.org/3/library/itertools.html#itertools.groupby) -.. [3] Proposal by GvR +.. [4] Proposal by GvR (https://mail.python.org/pipermail/python-ideas/2014-November/029953.html) -.. [4] Response by Steven D'Aprano +.. [5] Response by Steven D'Aprano (https://mail.python.org/pipermail/python-ideas/2014-November/029994.html) -.. [5] Split a sequence or generator using a predicate +.. [6] Split a sequence or generator using a predicate (http://code.activestate.com/recipes/578416-split-a-sequence-or-generator-us…) -.. [6] wrap unbounded generator to restrict its output +.. [7] wrap unbounded generator to restrict its output (http://code.activestate.com/recipes/66427-wrap-unbounded-generator-to-restr…) -.. [7] Post from Nick Coghlan mentioning asyncio +.. [8] Post from Nick Coghlan mentioning asyncio (https://mail.python.org/pipermail/python-ideas/2014-November/029961.html) -.. [8] Coroutines in asyncio +.. [9] Coroutines in asyncio (https://docs.python.org/3/library/asyncio-task.html#coroutines) -.. [9] Thread on comp.lang.python started by Steven D'Aprano +.. [10] Thread on comp.lang.python started by Steven D'Aprano (https://mail.python.org/pipermail/python-list/2014-November/680757.html) -.. [10] Tracker issue with Proof-of-Concept patch +.. [11] Tracker issue with Proof-of-Concept patch (http://bugs.python.org/issue22906) -.. [11] Post from Mark Shannon with alternate proposal +.. [12] Post from Mark Shannon with alternate proposal (https://mail.python.org/pipermail/python-dev/2014-November/137129.html) Copyright -- Repository URL: https://hg.python.org/peps

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cpython (2.7): pydoc: Add a note about setting PAGER to affect console output pagination.
by zach.ware 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/ac65f90c1214 changeset: 93618:ac65f90c1214 branch: 2.7 parent: 93613:ec21b41e588b user: Zachary Ware <zachary.ware(a)gmail.com> date: Wed Nov 26 23:44:25 2014 -0600 summary: pydoc: Add a note about setting PAGER to affect console output pagination. Suggested by James Lowden on docs@. files: Doc/library/pydoc.rst | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/Doc/library/pydoc.rst b/Doc/library/pydoc.rst --- a/Doc/library/pydoc.rst +++ b/Doc/library/pydoc.rst @@ -53,6 +53,10 @@ executed on that occasion. Use an ``if __name__ == '__main__':`` guard to only execute code when a file is invoked as a script and not just imported. +When printing output to the console, :program:`pydoc` attempts to paginate the +output for easier reading. If the :envvar:`PAGER` environment variable is set, +:program:`pydoc` will use its value as a pagination program. + Specifying a ``-w`` flag before the argument will cause HTML documentation to be written out to a file in the current directory, instead of displaying text on the console. -- Repository URL: https://hg.python.org/cpython

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cpython (merge 3.4 -> default): Merge with 3.4
by zach.ware 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/1c97f373fe49 changeset: 93617:1c97f373fe49 parent: 93615:b6ee02acaae9 parent: 93616:589c65dc528c user: Zachary Ware <zachary.ware(a)gmail.com> date: Wed Nov 26 23:56:10 2014 -0600 summary: Merge with 3.4 files: Doc/library/pydoc.rst | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/Doc/library/pydoc.rst b/Doc/library/pydoc.rst --- a/Doc/library/pydoc.rst +++ b/Doc/library/pydoc.rst @@ -51,6 +51,10 @@ executed on that occasion. Use an ``if __name__ == '__main__':`` guard to only execute code when a file is invoked as a script and not just imported. +When printing output to the console, :program:`pydoc` attempts to paginate the +output for easier reading. If the :envvar:`PAGER` environment variable is set, +:program:`pydoc` will use its value as a pagination program. + Specifying a ``-w`` flag before the argument will cause HTML documentation to be written out to a file in the current directory, instead of displaying text on the console. -- Repository URL: https://hg.python.org/cpython

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cpython (3.4): pydoc: Add a note about setting PAGER to affect console output pagination.
by zach.ware 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/589c65dc528c changeset: 93616:589c65dc528c branch: 3.4 parent: 93614:ebb8865dcf54 user: Zachary Ware <zachary.ware(a)gmail.com> date: Wed Nov 26 23:44:25 2014 -0600 summary: pydoc: Add a note about setting PAGER to affect console output pagination. Suggested by James Lowden on docs@. files: Doc/library/pydoc.rst | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/Doc/library/pydoc.rst b/Doc/library/pydoc.rst --- a/Doc/library/pydoc.rst +++ b/Doc/library/pydoc.rst @@ -51,6 +51,10 @@ executed on that occasion. Use an ``if __name__ == '__main__':`` guard to only execute code when a file is invoked as a script and not just imported. +When printing output to the console, :program:`pydoc` attempts to paginate the +output for easier reading. If the :envvar:`PAGER` environment variable is set, +:program:`pydoc` will use its value as a pagination program. + Specifying a ``-w`` flag before the argument will cause HTML documentation to be written out to a file in the current directory, instead of displaying text on the console. -- Repository URL: https://hg.python.org/cpython

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cpython (merge 3.4 -> default): Issue22780: reword NotImplemented docs to emphasise should
by ethan.furman 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/b6ee02acaae9 changeset: 93615:b6ee02acaae9 parent: 93612:d502b5d60e00 parent: 93614:ebb8865dcf54 user: Ethan Furman <ethan(a)stoneleaf.us> date: Wed Nov 26 21:17:53 2014 -0800 summary: Issue22780: reword NotImplemented docs to emphasise should files: Doc/library/constants.rst | 20 +++++++++++++++++--- Doc/library/numbers.rst | 2 ++ Doc/reference/datamodel.rst | 7 ++++++- 3 files changed, 25 insertions(+), 4 deletions(-) diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst --- a/Doc/library/constants.rst +++ b/Doc/library/constants.rst @@ -26,9 +26,23 @@ .. data:: NotImplemented - Special value which should be returned by the special methods - (:meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, etc.) to indicate - that the operation is not implemented with respect to the other type. + Special value which should be returned by the binary special methods + (e.g. :meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, :meth:`__rsub__`, + etc.) to indicate that the operation is not implemented with respect to + the other type; may be returned by the in-place binary special methods + (e.g. :meth:`__imul__`, :meth:`__iand__`, etc.) for the same purpose. + Its truth value is true. + +.. note:: + + When ``NotImplemented`` is returned, the interpreter will then try the + reflected operation on the other type, or some other fallback, depending + on the operator. If all attempted operations return ``NotImplemented``, the + interpreter will raise an appropriate exception. + + See + :ref:`implementing-the-arithmetic-operations` + for more details. .. data:: Ellipsis diff --git a/Doc/library/numbers.rst b/Doc/library/numbers.rst --- a/Doc/library/numbers.rst +++ b/Doc/library/numbers.rst @@ -110,6 +110,8 @@ MyFoo.register(Real) +.. _implementing-the-arithmetic-operations: + Implementing the arithmetic operations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -154,11 +154,16 @@ This type has a single value. There is a single object with this value. This object is accessed through the built-in name ``NotImplemented``. Numeric methods - and rich comparison methods may return this value if they do not implement the + and rich comparison methods should return this value if they do not implement the operation for the operands provided. (The interpreter will then try the reflected operation, or some other fallback, depending on the operator.) Its truth value is true. + See + :ref:`implementing-the-arithmetic-operations` + for more details. + + Ellipsis .. index:: object: Ellipsis -- Repository URL: https://hg.python.org/cpython

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cpython (3.4): (3.4) Issue22780: reword NotImplemented docs to emphasise should
by ethan.furman 27 Nov '14

27 Nov '14

https://hg.python.org/cpython/rev/ebb8865dcf54 changeset: 93614:ebb8865dcf54 branch: 3.4 parent: 93611:a498e599ce6a user: Ethan Furman <ethan(a)stoneleaf.us> date: Wed Nov 26 21:15:35 2014 -0800 summary: (3.4) Issue22780: reword NotImplemented docs to emphasise should files: Doc/library/constants.rst | 21 ++++++++++++++++++--- Doc/library/numbers.rst | 2 ++ Doc/reference/datamodel.rst | 7 ++++++- 3 files changed, 26 insertions(+), 4 deletions(-) diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst --- a/Doc/library/constants.rst +++ b/Doc/library/constants.rst @@ -26,9 +26,24 @@ .. data:: NotImplemented - Special value which can be returned by the "rich comparison" special methods - (:meth:`__eq__`, :meth:`__lt__`, and friends), to indicate that the comparison - is not implemented with respect to the other type. + Special value which should be returned by the binary special methods + (e.g. :meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, :meth:`__rsub__`, + etc.) to indicate that the operation is not implemented with respect to + the other type; may be returned by the in-place binary special methods + (e.g. :meth:`__imul__`, :meth:`__iand__`, etc.) for the same purpose. + Its truth value is true. + +.. note:: + + When ``NotImplemented`` is returned, the interpreter will then try the + reflected operation on the other type, or some other fallback, depending + on the operator. If all attempted operations return ``NotImplemented``, the + interpreter will raise an appropriate exception. + + See + :ref:`implementing-the-arithmetic-operations` + for more details. + .. data:: Ellipsis diff --git a/Doc/library/numbers.rst b/Doc/library/numbers.rst --- a/Doc/library/numbers.rst +++ b/Doc/library/numbers.rst @@ -110,6 +110,8 @@ MyFoo.register(Real) +.. _implementing-the-arithmetic-operations: + Implementing the arithmetic operations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -154,11 +154,16 @@ This type has a single value. There is a single object with this value. This object is accessed through the built-in name ``NotImplemented``. Numeric methods - and rich comparison methods may return this value if they do not implement the + and rich comparison methods should return this value if they do not implement the operation for the operands provided. (The interpreter will then try the reflected operation, or some other fallback, depending on the operator.) Its truth value is true. + See + :ref:`implementing-the-arithmetic-operations` + for more details. + + Ellipsis .. index:: object: Ellipsis -- Repository URL: https://hg.python.org/cpython

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