Mailman 3 April 2018 - Python-checkins

[2.7] bpo-27212: Modify islice recipe to consume initial values preceding start (GH-6195) (GH-6339)
by Raymond Hettinger April 2, 2018

April 2, 2018

https://github.com/python/cpython/commit/325191bd6b3a2d5e3012adee868f19baf3… commit: 325191bd6b3a2d5e3012adee868f19baf3e2c3ab branch: 2.7 author: Cheryl Sabella <cheryl.sabella(a)gmail.com> committer: Raymond Hettinger <rhettinger(a)users.noreply.github.com> date: 2018-04-01T22:29:01-07:00 summary: [2.7] bpo-27212: Modify islice recipe to consume initial values preceding start (GH-6195) (GH-6339) (cherry picked from commit da1734c58d2f97387ccc9676074717d38b044128) files: A Misc/… [View More]NEWS.d/next/Documentation/2018-03-22-19-23-04.bpo-27212.wrE5KR.rst M Doc/library/itertools.rst M Lib/test/test_itertools.py diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index 57ba4d45e9b2..17303dd01cef 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -411,12 +411,24 @@ loops that truncate the stream. # islice('ABCDEFG', 2, None) --> C D E F G # islice('ABCDEFG', 0, None, 2) --> A C E G s = slice(*args) - it = iter(xrange(s.start or 0, s.stop or sys.maxint, s.step or 1)) - nexti = next(it) - for i, element in enumerate(iterable): - if i == nexti: - yield element - nexti = next(it) + start, stop, step = s.start or 0, s.stop or sys.maxint, s.step or 1 + it = iter(xrange(start, stop, step))) + try: + nexti = next(it) + except StopIteration: + # Consume *iterable* up to the *start* position. + for i, element in izip(xrange(start), iterable): + pass + return + try: + for i, element in enumerate(iterable): + if i == nexti: + yield element + nexti = next(it) + except StopIteration: + # Consume to *stop*. + for i, element in izip(xrange(i + 1, stop), iterable): + pass If *start* is ``None``, then iteration starts at zero. If *step* is ``None``, then the step defaults to one. @@ -681,8 +693,8 @@ which incur interpreter overhead. "Return function(0), function(1), ..." return imap(function, count(start)) - def consume(iterator, n): - "Advance the iterator n-steps ahead. If n is none, consume entirely." + def consume(iterator, n=None): + "Advance the iterator n-steps ahead. If n is None, consume entirely." # Use functions that consume iterators at C speed. if n is None: # feed the entire iterator into a zero-length deque diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py index 1e6db3426e4f..04279792065e 100644 --- a/Lib/test/test_itertools.py +++ b/Lib/test/test_itertools.py @@ -802,6 +802,7 @@ def test_islice(self): (10, 20, 3), (10, 3, 20), (10, 20), + (10, 10), (10, 3), (20,) ]: @@ -826,6 +827,10 @@ def test_islice(self): self.assertEqual(list(islice(it, 3)), range(3)) self.assertEqual(list(it), range(3, 10)) + it = iter(range(10)) + self.assertEqual(list(islice(it, 3, 3)), []) + self.assertEqual(list(it), range(3, 10)) + # Test invalid arguments self.assertRaises(TypeError, islice, xrange(10)) self.assertRaises(TypeError, islice, xrange(10), 1, 2, 3, 4) @@ -1084,6 +1089,48 @@ def test_takewhile(self): self.assertEqual(list(takewhile(lambda x: x<5, [1,4,6,4,1])), [1,4]) +class TestPurePythonRoughEquivalents(unittest.TestCase): + + @staticmethod + def islice(iterable, *args): + s = slice(*args) + start, stop, step = s.start or 0, s.stop or sys.maxint, s.step or 1 + it = iter(xrange(start, stop, step)) + try: + nexti = next(it) + except StopIteration: + # Consume *iterable* up to the *start* position. + for i, element in izip(xrange(start), iterable): + pass + return + try: + for i, element in enumerate(iterable): + if i == nexti: + yield element + nexti = next(it) + except StopIteration: + # Consume to *stop*. + for i, element in izip(xrange(i + 1, stop), iterable): + pass + + def test_islice_recipe(self): + self.assertEqual(list(self.islice('ABCDEFG', 2)), list('AB')) + self.assertEqual(list(self.islice('ABCDEFG', 2, 4)), list('CD')) + self.assertEqual(list(self.islice('ABCDEFG', 2, None)), list('CDEFG')) + self.assertEqual(list(self.islice('ABCDEFG', 0, None, 2)), list('ACEG')) + # Test items consumed. + it = iter(xrange(10)) + self.assertEqual(list(self.islice(it, 3)), range(3)) + self.assertEqual(list(it), range(3, 10)) + it = iter(xrange(10)) + self.assertEqual(list(self.islice(it, 3, 3)), []) + self.assertEqual(list(it), range(3, 10)) + # Test that slice finishes in predictable state. + c = count() + self.assertEqual(list(self.islice(c, 1, 3, 50)), [1]) + self.assertEqual(next(c), 3) + + class TestGC(unittest.TestCase): def makecycle(self, iterator, container): @@ -1577,6 +1624,17 @@ def __init__(self, newarg=None, *args): ... "Return function(0), function(1), ..." ... return imap(function, count(start)) +>>> import collections +>>> def consume(iterator, n=None): +... "Advance the iterator n-steps ahead. If n is None, consume entirely." +... # Use functions that consume iterators at C speed. +... if n is None: +... # feed the entire iterator into a zero-length deque +... collections.deque(iterator, maxlen=0) +... else: +... # advance to the empty slice starting at position n +... next(islice(iterator, n, n), None) + >>> def nth(iterable, n, default=None): ... "Returns the nth item or a default value" ... return next(islice(iterable, n, None), default) @@ -1678,6 +1736,14 @@ def __init__(self, newarg=None, *args): >>> list(islice(tabulate(lambda x: 2*x), 4)) [0, 2, 4, 6] +>>> it = iter(xrange(10)) +>>> consume(it, 3) +>>> next(it) +3 +>>> consume(it) +>>> next(it, 'Done') +'Done' + >>> nth('abcde', 3) 'd' @@ -1753,7 +1819,8 @@ def __init__(self, newarg=None, *args): def test_main(verbose=None): test_classes = (TestBasicOps, TestVariousIteratorArgs, TestGC, RegressionTests, LengthTransparency, - SubclassWithKwargsTest, TestExamples) + SubclassWithKwargsTest, TestExamples, + TestPurePythonRoughEquivalents) test_support.run_unittest(*test_classes) # verify reference counting diff --git a/Misc/NEWS.d/next/Documentation/2018-03-22-19-23-04.bpo-27212.wrE5KR.rst b/Misc/NEWS.d/next/Documentation/2018-03-22-19-23-04.bpo-27212.wrE5KR.rst new file mode 100644 index 000000000000..5910d2c17342 --- /dev/null +++ b/Misc/NEWS.d/next/Documentation/2018-03-22-19-23-04.bpo-27212.wrE5KR.rst @@ -0,0 +1,2 @@ +Modify documentation for the :func:`islice` recipe to consume initial values +up to the start index. 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bpo-20104: Add os.posix_spawn documentation. (GH-6334)
by Miss Islington (bot) April 1, 2018

April 1, 2018

https://github.com/python/cpython/commit/ab8457232121dfdfb1d4bfcf806a842fbe… commit: ab8457232121dfdfb1d4bfcf806a842fbe402722 branch: 3.7 author: Miss Islington (bot) <31488909+miss-islington(a)users.noreply.github.com> committer: GitHub <noreply(a)github.com> date: 2018-04-01T12:13:37-07:00 summary: bpo-20104: Add os.posix_spawn documentation. (GH-6334) (cherry picked from commit 79760ed256987cead08d668b95675afba6b3760f) Co-authored-by: Gregory P. Smith <greg(a)krypto.org> … [View More]

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bpo-20104: Add os.posix_spawn documentation. (#6334)
by Gregory P. Smith April 1, 2018

April 1, 2018

https://github.com/python/cpython/commit/79760ed256987cead08d668b95675afba6… commit: 79760ed256987cead08d668b95675afba6b3760f branch: master author: Gregory P. Smith <greg(a)krypto.org> committer: GitHub <noreply(a)github.com> date: 2018-04-01T12:01:48-07:00 summary: bpo-20104: Add os.posix_spawn documentation. (#6334) files: M Doc/library/os.rst diff --git a/Doc/library/os.rst b/Doc/library/os.rst index bae432d33b0b..e685b33302bd 100644 --- a/Doc/library/os.rst +++ b/Doc/library/… [View More]

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Allow dynamic creation of generic dataclasses (GH-6319) (GH-6320)
by Ivan Levkivskyi April 1, 2018

April 1, 2018

https://github.com/python/cpython/commit/d063ad8962a83f41fccdca774b728c3826… commit: d063ad8962a83f41fccdca774b728c3826639f62 branch: 3.7 author: Miss Islington (bot) <31488909+miss-islington(a)users.noreply.github.com> committer: Ivan Levkivskyi <levkivskyi(a)gmail.com> date: 2018-04-01T12:33:13+01:00 summary: Allow dynamic creation of generic dataclasses (GH-6319) (GH-6320) (cherry picked from commit 5a7092de1226a95a50f0f384eea8ddb288959249) Co-authored-by: Ivan Levkivskyi <… [View More]levkivskyi(a)gmail.com> files: M Lib/dataclasses.py M Lib/test/test_dataclasses.py diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index bd7252c683ca..04e07f8cf8c2 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -1004,7 +1004,9 @@ class C(Base): anns[name] = tp namespace['__annotations__'] = anns - cls = type(cls_name, bases, namespace) + # We use `types.new_class()` instead of simply `type()` to allow dynamic creation + # of generic dataclassses. + cls = types.new_class(cls_name, bases, {}, lambda ns: ns.update(namespace)) return dataclass(cls, init=init, repr=repr, eq=eq, order=order, unsafe_hash=unsafe_hash, frozen=frozen) diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index 5cd424cf5760..26bfc4e75a00 100755 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -8,7 +8,7 @@ import inspect import unittest from unittest.mock import Mock -from typing import ClassVar, Any, List, Union, Tuple, Dict, Generic, TypeVar +from typing import ClassVar, Any, List, Union, Tuple, Dict, Generic, TypeVar, Optional from collections import deque, OrderedDict, namedtuple from functools import total_ordering @@ -1690,6 +1690,23 @@ def new_method(self): c = Alias(10, 1.0) self.assertEqual(c.new_method(), 1.0) + def test_generic_dynamic(self): + T = TypeVar('T') + + @dataclass + class Parent(Generic[T]): + x: T + Child = make_dataclass('Child', [('y', T), ('z', Optional[T], None)], + bases=(Parent[int], Generic[T]), namespace={'other': 42}) + self.assertIs(Child[int](1, 2).z, None) + self.assertEqual(Child[int](1, 2, 3).z, 3) + self.assertEqual(Child[int](1, 2, 3).other, 42) + # Check that type aliases work correctly. + Alias = Child[T] + self.assertEqual(Alias[int](1, 2).x, 1) + # Check MRO resolution. + self.assertEqual(Child.__mro__, (Child, Parent, Generic, object)) + def test_helper_replace(self): @dataclass(frozen=True) class C: [View Less]

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Daily reference leaks (4243df51fe43): sum=4
by solipsis＠pitrou.net April 1, 2018

April 1, 2018

results for 4243df51fe43 on branch "default" -------------------------------------------- test_functools leaked [0, 3, 1] memory blocks, sum=4 Command line was: ['./python', '-m', 'test.regrtest', '-uall', '-R', '3:3:/home/psf-users/antoine/refleaks/reflogO6YRBC', '--timeout', '7200']

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[2.7] bpo-33132: Fix reference counting issues in the compiler. (GH-6209). (GH-6322)
by Serhiy Storchaka April 1, 2018

April 1, 2018

https://github.com/python/cpython/commit/72f3e0887500e00867fa16ce5aaab12fae… commit: 72f3e0887500e00867fa16ce5aaab12fae853b63 branch: 2.7 author: Serhiy Storchaka <storchaka(a)gmail.com> committer: GitHub <noreply(a)github.com> date: 2018-04-01T10:26:33+03:00 summary: [2.7] bpo-33132: Fix reference counting issues in the compiler. (GH-6209). (GH-6322) (cherry picked from commit a95d98607efe0c43475b354543e49bf8e240bc6f) Co-authored-by: Serhiy Storchaka <storchaka(a)gmail.com… [View More]> files: M Python/compile.c diff --git a/Python/compile.c b/Python/compile.c index 9c9b23698520..4fe69e12bf84 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -1075,6 +1075,15 @@ compiler_addop_j(struct compiler *c, int opcode, basicblock *b, int absolute) return 0; \ } +/* Same as ADDOP_O, but steals a reference. */ +#define ADDOP_N(C, OP, O, TYPE) { \ + if (!compiler_addop_o((C), (OP), (C)->u->u_ ## TYPE, (O))) { \ + Py_DECREF((O)); \ + return 0; \ + } \ + Py_DECREF((O)); \ +} + #define ADDOP_NAME(C, OP, O, TYPE) { \ if (!compiler_addop_name((C), (OP), (C)->u->u_ ## TYPE, (O))) \ return 0; \ @@ -1890,8 +1899,7 @@ compiler_import_as(struct compiler *c, identifier name, identifier asname) dot ? dot - src : strlen(src)); if (!attr) return 0; - ADDOP_O(c, LOAD_ATTR, attr, names); - Py_DECREF(attr); + ADDOP_N(c, LOAD_ATTR, attr, names); src = dot + 1; } } @@ -1923,8 +1931,7 @@ compiler_import(struct compiler *c, stmt_ty s) if (level == NULL) return 0; - ADDOP_O(c, LOAD_CONST, level, consts); - Py_DECREF(level); + ADDOP_N(c, LOAD_CONST, level, consts); ADDOP_O(c, LOAD_CONST, Py_None, consts); ADDOP_NAME(c, IMPORT_NAME, alias->name, names); @@ -1959,8 +1966,7 @@ compiler_from_import(struct compiler *c, stmt_ty s) { int i, n = asdl_seq_LEN(s->v.ImportFrom.names); - PyObject *names = PyTuple_New(n); - PyObject *level; + PyObject *level, *names; static PyObject *empty_string; if (!empty_string) { @@ -1969,9 +1975,6 @@ compiler_from_import(struct compiler *c, stmt_ty s) return 0; } - if (!names) - return 0; - if (s->v.ImportFrom.level == 0 && c->c_flags && !(c->c_flags->cf_flags & CO_FUTURE_ABSOLUTE_IMPORT)) level = PyInt_FromLong(-1); @@ -1979,9 +1982,13 @@ compiler_from_import(struct compiler *c, stmt_ty s) level = PyInt_FromLong(s->v.ImportFrom.level); if (!level) { - Py_DECREF(names); return 0; } + ADDOP_N(c, LOAD_CONST, level, consts); + + names = PyTuple_New(n); + if (!names) + return 0; /* build up the names */ for (i = 0; i < n; i++) { @@ -1992,16 +1999,12 @@ compiler_from_import(struct compiler *c, stmt_ty s) if (s->lineno > c->c_future->ff_lineno && s->v.ImportFrom.module && !strcmp(PyString_AS_STRING(s->v.ImportFrom.module), "__future__")) { - Py_DECREF(level); Py_DECREF(names); return compiler_error(c, "from __future__ imports must occur " "at the beginning of the file"); } + ADDOP_N(c, LOAD_CONST, names, consts); - ADDOP_O(c, LOAD_CONST, level, consts); - Py_DECREF(level); - ADDOP_O(c, LOAD_CONST, names, consts); - Py_DECREF(names); if (s->v.ImportFrom.module) { ADDOP_NAME(c, IMPORT_NAME, s->v.ImportFrom.module, names); } @@ -2024,7 +2027,6 @@ compiler_from_import(struct compiler *c, stmt_ty s) store_name = alias->asname; if (!compiler_nameop(c, store_name, Store)) { - Py_DECREF(names); return 0; } } @@ -2391,8 +2393,7 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx) "param invalid for local variable"); return 0; } - ADDOP_O(c, op, mangled, varnames); - Py_DECREF(mangled); + ADDOP_N(c, op, mangled, varnames); return 1; case OP_GLOBAL: switch (ctx) { [View Less]

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