Mailman 3 May 2019 - Python-Dev

ast changes for "debug" f-strings
by Eric V. Smith 20 May '19

20 May '19

I added an optional "expr_text" field to the FormattedValue node, which represents the text of the expression in a "debug" f-string expression. So in f'{x=}', expr_text would be "x=". This strictly speaking isn't necessary. I could have added another Constant node for "x=" and left FormattedValue alone. I didn't for three reasons: it was expedient; it didn't require a lot of surgery to f-string parsing, which the extra Constant node would require; and it allowed the Python/ast_unparse.c code to produce a string that was more consistent with input string. Now that I have more time, I'm rethinking this decision. I'd rather not have the extra churn that modifying the ast node will cause to downstream code. Someone (Serhiy?) already pointed this out somewhere, but now I can't find the original message. But the issue of the fidelity of ast_unparse is still there. I think the only place this code is used is "from __future__ import annotations", but for all I know there's a plan to use it elsewhere. Does anyone care that f'{x=}' would become f'x={x!r}' if I removed expr_text from the FormattedValue node? This isn't the only place where ast_unparse isn't exact with what it produces. It's not designed to give the exact source text back, just something equivalent. But it's not clear to me how equivalent it needs to be. Even if I did add the extra Constant node, then you'd have the following discrepancy: f'value: {x=}' would produce: [Expr(value=JoinedStr(values=[Constant(value='value: ', kind=None), Constant(value='x=', kind=None), FormattedValue(value=Name(id='x', ctx=Load()), conversion=114, format_spec=None, expr_text='x=')]))] Note that there are two consecutive Constant nodes here. So this: f'value: x={x!r}' would produce the slightly different: [Expr(value=JoinedStr(values=[Constant(value='value: x=', kind=None), FormattedValue(value=Name(id='x', ctx=Load()), conversion=114, format_spec=None)]))] Note that there is a single Constant node, with the combined string in it. I'm not sure how much we care about all of this, but let me know if you have a strong feeling about it. My suggestion for the 3.8b1 release is to add the extra Constant node and remove expr_text from the FormattedValue node. This would at least mean that there's no change to the ast definitions due to this feature. If we decide that the two consecutive Constant nodes generated by f'value: {x=}' need to be combined, then we can do that post 3.8b1. But it's a lot more work to combine the nodes while the f-string is being compiled. Let me know your thoughts, since time is of the essence. Eric

3 3

Plan to accept PEP 544, PEP 586, PEP 589, PEP 591 -- last call for discussion
by Guido van Rossum 20 May '19

20 May '19

Please send all discussions about these PEPs to the typing-sig mailing list, so we have the archives all in one place. Read the full message here: https://mail.python.org/archives/list/typing-sig@python.org/thread/GCI2TF43… -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him/his **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-…>

2 1

Feature request: Change a Dependency Package Version During Package Initiation
by Q 20 May '19

20 May '19

A lot of the Python code we use in production are used directly as imports in other python distributions (such as the python comes with the finite element software Abaqus and MSC Marc), many packages (such as matplotlib, numpy) that may have varying versioned dependencies. I was wondering if this could be expanded to allow a version to be set within a package and have that propagate to all modules in that package. For example in the root init.py if I set multiversion(tornado, 2.2.1) then all modules in that package will use tornado 2.2.1 when I import tornado. See a relevant issue on github: https://github.com/mitsuhiko/multiversion/issues/1 Thank you! Qiang

5 7

PEP 581 (Using GitHub issues for CPython) is accepted
by Barry Warsaw 18 May '19

18 May '19

As the BDFL-Delegate for PEP 581, and with the unanimous backing of the rest of the Steering Council, I hereby Accept this PEP. We would like to thank Mariatta for championing PEP 581, and to all the contributors to the discussion, both pro and con. We appreciate your candor and respect for your fellow developers. The SC believes that this migration is in the best interest of the Python community, and we look forward to the elaboration of the detailed migration plan (PEP 588). We also extend our heartfelt thanks Berker, Ezio, and everyone who has helped develop and maintain Roundup and bugs.python.org over the years. bpo has been a critical component for Python development for a very long time, and we all greatly appreciate the time, effort, and devotion you have put into this resource. https://www.python.org/dev/peps/pep-0581/ Onward we go! The migration will be a large effort, with much planning, development, and testing, and we welcome volunteers who wish to help make it a reality. I look forward to your contributions on PEP 588 and the actual work of migrating issues to GitHub. Cheers, -Barry (BDFL-Delegate, and on behalf of the Python Steering Council)

14 23

Merge ?
by Srinivas Reddy Thatiparthy 18 May '19

18 May '19

Pls take a look here https://github.com/python/cpython/pull/9882 If it not okay to document that >>> mock.assert_has_calls([]) does not raise an exception; then i will go ahead and close the pr. Best Regards, Srinivas Reddy Thatiparthy.

1 0

Summary of Python tracker Issues
by Python tracker 17 May '19

17 May '19

ACTIVITY SUMMARY (2019-05-10 - 2019-05-17) Python tracker at https://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue. Do NOT respond to this message. Issues counts and deltas: open 7067 (-17) closed 41633 (+91) total 48700 (+74) Open issues with patches: 2861 Issues opened (56) ================== #36084: Threading: add builtin TID attribute to Thread objects https://bugs.python.org/issue36084 reopened by vstinner #36801: Wait for connection_lost in StreamWriter.drain https://bugs.python.org/issue36801 reopened by asvetlov #36802: Revert back StreamWriter awrite/aclose but provide await write https://bugs.python.org/issue36802 reopened by vstinner #36817: Add = to f-strings for easier debugging. https://bugs.python.org/issue36817 reopened by pablogsal #36876: Global C variables are a problem. https://bugs.python.org/issue36876 opened by eric.snow #36877: [meta] Move fields from _PyRuntimeState to PyInterpreterState. https://bugs.python.org/issue36877 opened by eric.snow #36878: ast.parse with type_comments=True should allow extra text afte https://bugs.python.org/issue36878 opened by msullivan #36879: bug with round() and "numpy floats" https://bugs.python.org/issue36879 opened by Scaler #36880: Returning None from a callback with restype py_object decremen https://bugs.python.org/issue36880 opened by dgelessus #36881: isinstance raises TypeError for metaclass with metaclass=ABCMe https://bugs.python.org/issue36881 opened by emanspeaks #36882: 在ctypes里调用C库返回c_char_p类型时的问题 https://bugs.python.org/issue36882 opened by fy2099 #36885: Make makeunicode.py script more readable https://bugs.python.org/issue36885 opened by scoder #36887: Add integer square root, math.isqrt https://bugs.python.org/issue36887 opened by mark.dickinson #36888: Create a way to check that the parent process is alive for dea https://bugs.python.org/issue36888 opened by tomMoral #36889: Merge StreamWriter and StreamReader into just asyncio.Stream https://bugs.python.org/issue36889 opened by asvetlov #36890: python-3.7.3-macosx10.6.pkg verification error on macOS 10.6 S https://bugs.python.org/issue36890 opened by steve_314 #36891: Additional startup plugin for vendors https://bugs.python.org/issue36891 opened by vx1920 #36892: "Modules" section in Tutorial contains incorrect description a https://bugs.python.org/issue36892 opened by musou1500 #36893: email.headerregistry.Address blocks Unicode local part addr_sp https://bugs.python.org/issue36893 opened by dracos #36894: test_multiprocessing_spawn regression on Windows https://bugs.python.org/issue36894 opened by pitrou #36895: time.clock() marked for removal in 3.8 – still there. https://bugs.python.org/issue36895 opened by mbussonn #36896: clarify in types.rst that FunctionTypes & co constructors don https://bugs.python.org/issue36896 opened by mbussonn #36897: shlex doesn't differentiate escaped characters in output https://bugs.python.org/issue36897 opened by Matthew Gamble #36898: Add parameter @case_sensitive to glob and rglob in pathlib https://bugs.python.org/issue36898 opened by Chuang Men #36901: Fix leaks in /PC/bdist_wininst/install.c https://bugs.python.org/issue36901 opened by cheryl.sabella #36904: Implement _PyStack_UnpackDict() with a single allocation https://bugs.python.org/issue36904 opened by jdemeyer #36905: test_typing.GetTypeHintTests.test_get_type_hints_modules_forwa https://bugs.python.org/issue36905 opened by xtreak #36906: Compile time textwrap.dedent() equivalent for str or bytes lit https://bugs.python.org/issue36906 opened by gregory.p.smith #36907: Crash due to borrowed references in _PyStack_UnpackDict() https://bugs.python.org/issue36907 opened by jdemeyer #36908: "This module is always available" is confusing https://bugs.python.org/issue36908 opened by nedbat #36910: Certain Malformed email causes email.parser to throw Attribute https://bugs.python.org/issue36910 opened by msapiro #36913: Missing documentation for decorators https://bugs.python.org/issue36913 opened by tomerv #36917: ast.NodeVisitor no longer calls visit_Str https://bugs.python.org/issue36917 opened by Anthony Sottile #36918: ValueError warning in test_urllib due to io.IOBase destructor https://bugs.python.org/issue36918 opened by xtreak #36919: Exception from 'compile' reports a newline char not present in https://bugs.python.org/issue36919 opened by BCSharp #36921: Deprecate yield from and @coroutine in asyncio https://bugs.python.org/issue36921 opened by asvetlov #36922: Implement Py_TPFLAGS_METHOD_DESCRIPTOR https://bugs.python.org/issue36922 opened by jdemeyer #36924: Simplify implementation of classmethod_descriptor.__call__ https://bugs.python.org/issue36924 opened by jdemeyer #36926: Implement methoddescr_call without _PyMethodDef_RawFastCallDic https://bugs.python.org/issue36926 opened by jdemeyer #36927: traceback docstrings should explicitly state return values ins https://bugs.python.org/issue36927 opened by Aaron Hall #36929: Other Python _io implementations may not expose _io in their t https://bugs.python.org/issue36929 opened by tekknolagi #36932: asyncio-task.rst could use proper deprecated-removed directive https://bugs.python.org/issue36932 opened by mbussonn #36933: sys.set_coroutine_wrapper documented as to be removed in 3.8 ( https://bugs.python.org/issue36933 opened by mbussonn #36935: bpo-35813 introduced usage of the deprecated PyErr_SetFromWind https://bugs.python.org/issue36935 opened by ZackerySpytz #36936: CALL_FUNCTION_KW opcode: keyword names must be non-empty https://bugs.python.org/issue36936 opened by jdemeyer #36937: New _PyObject_MakeTpCall() function https://bugs.python.org/issue36937 opened by jdemeyer #36940: Update Py_FrozenMain() for _PyCoreConfig (PEP 587) https://bugs.python.org/issue36940 opened by vstinner #36941: Windows build changes for Windows ARM64 https://bugs.python.org/issue36941 opened by Paul Monson #36942: Windows code changes for Windows ARM64 https://bugs.python.org/issue36942 opened by Paul Monson #36943: Windows test changes for Windows ARM64 https://bugs.python.org/issue36943 opened by Paul Monson #36944: Add support for ARM64 to libffi https://bugs.python.org/issue36944 opened by Paul Monson #36945: Add _PyPreConfig.configure_locale: allow to leave LC_CTYPE unc https://bugs.python.org/issue36945 opened by vstinner #36946: Possible signed integer overflow in slice handling https://bugs.python.org/issue36946 opened by ZackerySpytz #36947: [Good first issue] Fix 3.3.3.1 Metaclasses Documentation https://bugs.python.org/issue36947 opened by Nicholas Matthews #36948: NameError in urllib.request.URLopener.retrieve https://bugs.python.org/issue36948 opened by xtreak #36949: WeakSet.__repr__ and __str__ do not show contents of the set https://bugs.python.org/issue36949 opened by steve.dower Most recent 15 issues with no replies (15) ========================================== #36949: WeakSet.__repr__ and __str__ do not show contents of the set https://bugs.python.org/issue36949 #36948: NameError in urllib.request.URLopener.retrieve https://bugs.python.org/issue36948 #36944: Add support for ARM64 to libffi https://bugs.python.org/issue36944 #36943: Windows test changes for Windows ARM64 https://bugs.python.org/issue36943 #36940: Update Py_FrozenMain() for _PyCoreConfig (PEP 587) https://bugs.python.org/issue36940 #36933: sys.set_coroutine_wrapper documented as to be removed in 3.8 ( https://bugs.python.org/issue36933 #36932: asyncio-task.rst could use proper deprecated-removed directive https://bugs.python.org/issue36932 #36926: Implement methoddescr_call without _PyMethodDef_RawFastCallDic https://bugs.python.org/issue36926 #36924: Simplify implementation of classmethod_descriptor.__call__ https://bugs.python.org/issue36924 #36922: Implement Py_TPFLAGS_METHOD_DESCRIPTOR https://bugs.python.org/issue36922 #36921: Deprecate yield from and @coroutine in asyncio https://bugs.python.org/issue36921 #36905: test_typing.GetTypeHintTests.test_get_type_hints_modules_forwa https://bugs.python.org/issue36905 #36901: Fix leaks in /PC/bdist_wininst/install.c https://bugs.python.org/issue36901 #36896: clarify in types.rst that FunctionTypes & co constructors don https://bugs.python.org/issue36896 #36889: Merge StreamWriter and StreamReader into just asyncio.Stream https://bugs.python.org/issue36889 Most recent 15 issues waiting for review (15) ============================================= #36948: NameError in urllib.request.URLopener.retrieve https://bugs.python.org/issue36948 #36946: Possible signed integer overflow in slice handling https://bugs.python.org/issue36946 #36945: Add _PyPreConfig.configure_locale: allow to leave LC_CTYPE unc https://bugs.python.org/issue36945 #36943: Windows test changes for Windows ARM64 https://bugs.python.org/issue36943 #36942: Windows code changes for Windows ARM64 https://bugs.python.org/issue36942 #36941: Windows build changes for Windows ARM64 https://bugs.python.org/issue36941 #36937: New _PyObject_MakeTpCall() function https://bugs.python.org/issue36937 #36936: CALL_FUNCTION_KW opcode: keyword names must be non-empty https://bugs.python.org/issue36936 #36935: bpo-35813 introduced usage of the deprecated PyErr_SetFromWind https://bugs.python.org/issue36935 #36932: asyncio-task.rst could use proper deprecated-removed directive https://bugs.python.org/issue36932 #36929: Other Python _io implementations may not expose _io in their t https://bugs.python.org/issue36929 #36927: traceback docstrings should explicitly state return values ins https://bugs.python.org/issue36927 #36926: Implement methoddescr_call without _PyMethodDef_RawFastCallDic https://bugs.python.org/issue36926 #36924: Simplify implementation of classmethod_descriptor.__call__ https://bugs.python.org/issue36924 #36922: Implement Py_TPFLAGS_METHOD_DESCRIPTOR https://bugs.python.org/issue36922 Top 10 most discussed issues (10) ================================= #36867: Make semaphore_tracker track other system resources https://bugs.python.org/issue36867 11 msgs #36887: Add integer square root, math.isqrt https://bugs.python.org/issue36887 11 msgs #36763: PEP 587: Rework initialization API to prepare second version o https://bugs.python.org/issue36763 10 msgs #36917: ast.NodeVisitor no longer calls visit_Str https://bugs.python.org/issue36917 10 msgs #36870: test_asyncio: test_drain_raises() fails randomly on Windows https://bugs.python.org/issue36870 9 msgs #36880: Returning None from a callback with restype py_object decremen https://bugs.python.org/issue36880 9 msgs #36895: time.clock() marked for removal in 3.8 – still there. https://bugs.python.org/issue36895 9 msgs #36908: "This module is always available" is confusing https://bugs.python.org/issue36908 8 msgs #36945: Add _PyPreConfig.configure_locale: allow to leave LC_CTYPE unc https://bugs.python.org/issue36945 8 msgs #35495: argparse does not honor default argument for nargs=argparse.RE https://bugs.python.org/issue35495 7 msgs Issues closed (89) ================== #1257: atexit errors should result in nonzero exit code https://bugs.python.org/issue1257 closed by vstinner #2921: enable embedding: declare/#define only py* symbols in #include https://bugs.python.org/issue2921 closed by vstinner #3020: doctest should have lib2to3 integration https://bugs.python.org/issue3020 closed by scoder #3620: test_smtplib is flaky https://bugs.python.org/issue3620 closed by SilentGhost #6584: gzip module has no custom exception https://bugs.python.org/issue6584 closed by serhiy.storchaka #10991: trace fails when test imported a temporary file https://bugs.python.org/issue10991 closed by brett.cannon #13320: _remove_visual_c_ref in distutils.msvc9compiler causes DLL loa https://bugs.python.org/issue13320 closed by vstinner #13493: Import error with embedded python on AIX 6.1 https://bugs.python.org/issue13493 closed by vstinner #14228: Don't display traceback when import site is interrupted by CTR https://bugs.python.org/issue14228 closed by vstinner #14353: Proper gettext support in locale module https://bugs.python.org/issue14353 closed by benjamin.peterson #16100: Compiling vim with Python 3.3 support fails https://bugs.python.org/issue16100 closed by zach.ware #16961: No regression tests for -E and individual environment vars https://bugs.python.org/issue16961 closed by vstinner #17679: sysconfig generation uses some env variables multiple times https://bugs.python.org/issue17679 closed by vstinner #19175: Erroneous reference to "integer" in format string grammar https://bugs.python.org/issue19175 closed by cheryl.sabella #19216: stat cache for import bootstrap https://bugs.python.org/issue19216 closed by vstinner #21202: Naming a file` io.py` causes cryptic error message https://bugs.python.org/issue21202 closed by vstinner #21563: Segv during call to builtin_execfile in application embedding https://bugs.python.org/issue21563 closed by vstinner #22747: Interpreter fails in initialize on systems where HAVE_LANGINFO https://bugs.python.org/issue22747 closed by vstinner #23603: Embedding Python3.4 - PyUnicode_Check fails (MinGW-W64) https://bugs.python.org/issue23603 closed by vstinner #24280: Unable to install Python https://bugs.python.org/issue24280 closed by vstinner #24758: unittest.mock.Mock's new "unsafe" feature needs a better error https://bugs.python.org/issue24758 closed by xtreak #26122: Isolated mode doesn't ignore PYTHONHASHSEED https://bugs.python.org/issue26122 closed by vstinner #26480: add a flag that will not give the set a sys.stdin https://bugs.python.org/issue26480 closed by vstinner #26707: plistlib fails to parse bplist with 0x80 UID values https://bugs.python.org/issue26707 closed by serhiy.storchaka #26891: CPython doesn't work when you disable refcounting https://bugs.python.org/issue26891 closed by vstinner #29818: Py_SetStandardStreamEncoding leads to a memory error in debug https://bugs.python.org/issue29818 closed by vstinner #30464: gammavariate has a wrong comment https://bugs.python.org/issue30464 closed by mark.dickinson #30633: Python 3.6.1 installation issues on OpenSuse 42.1: ModuleNotFo https://bugs.python.org/issue30633 closed by vstinner #31473: Debug hooks on memory allocators are not thread safe (serialno https://bugs.python.org/issue31473 closed by vstinner #32177: spammers mine emails from bugs.python.org https://bugs.python.org/issue32177 closed by SilentGhost #32231: -bb option should override -W options https://bugs.python.org/issue32231 closed by vstinner #32832: doctest should support custom ps1/ps2 prompts https://bugs.python.org/issue32832 closed by cheryl.sabella #32995: Add a glossary entry for context variables https://bugs.python.org/issue32995 closed by cheryl.sabella #33123: Path.unlink should have a missing_ok parameter https://bugs.python.org/issue33123 closed by pitrou #33303: ElementTree Comment text isn't escaped https://bugs.python.org/issue33303 closed by scoder #33882: doc Mention breakpoint() in debugger-related FAQ https://bugs.python.org/issue33882 closed by matrixise #34152: performance of some list slice assignment margin cases can be https://bugs.python.org/issue34152 closed by pablogsal #34408: possible null pointer dereference in pystate.c https://bugs.python.org/issue34408 closed by pablogsal #34424: Unicode names break email header https://bugs.python.org/issue34424 closed by cheryl.sabella #34484: Unicode HOWTO incorrectly refers to Private Use Area for surro https://bugs.python.org/issue34484 closed by akuchling #34509: Starting to use gcc-8 on CI https://bugs.python.org/issue34509 closed by zach.ware #34579: test_embed.InitConfigTests fail on AIX https://bugs.python.org/issue34579 closed by vstinner #34682: Typo reports on docs@ https://bugs.python.org/issue34682 closed by cheryl.sabella #35138: timeit documentation should have example with function argumen https://bugs.python.org/issue35138 closed by vstinner #35589: BaseSelectorEventLoop.sock_sendall() performance regression: e https://bugs.python.org/issue35589 closed by asvetlov #36008: [good first issue] Update documentation for 3.8 https://bugs.python.org/issue36008 closed by cheryl.sabella #36471: PEP 432, PEP 587: Add _Py_RunMain() https://bugs.python.org/issue36471 closed by vstinner #36474: RecursionError resets trace function set via sys.settrace https://bugs.python.org/issue36474 closed by blueyed #36594: Undefined behavior due to incorrect usage of %p in format stri https://bugs.python.org/issue36594 closed by brett.cannon #36618: clang expects memory aligned on 16 bytes, but pymalloc aligns https://bugs.python.org/issue36618 closed by vstinner #36620: Documentation missing parameter for Itertools.zip_longest https://bugs.python.org/issue36620 closed by rhettinger #36684: codecov.io code coverage has not updated since 2019-04-13 https://bugs.python.org/issue36684 closed by inada.naoki #36725: Reference leak regression with Python3.8a3 https://bugs.python.org/issue36725 closed by vstinner #36728: Remove PyEval_ReInitThreads() from the public C API https://bugs.python.org/issue36728 closed by vstinner #36748: Optimize textio write buffering https://bugs.python.org/issue36748 closed by inada.naoki #36749: PPC64 AIX 3.x: compilation issue, linker fails to locate symbo https://bugs.python.org/issue36749 closed by vstinner #36751: Changes in the inspect module for PEP 570 https://bugs.python.org/issue36751 closed by pablogsal #36760: subprocess.run fails with capture_output=True and stderr=STDOU https://bugs.python.org/issue36760 closed by gregory.p.smith #36789: Unicode HOWTO incorrectly states that UTF-8 contains no zero b https://bugs.python.org/issue36789 closed by cheryl.sabella #36791: sum() relies on C signed overflow behaviour https://bugs.python.org/issue36791 closed by serhiy.storchaka #36799: Typo in ctypes documentation https://bugs.python.org/issue36799 closed by matrixise #36807: IDLE doesn't call os.fsync() https://bugs.python.org/issue36807 closed by terry.reedy #36818: Add PyInterpreterState.runtime. https://bugs.python.org/issue36818 closed by vstinner #36822: Minor grammatical fix in glossary.rst https://bugs.python.org/issue36822 closed by pablogsal #36845: ipaddres.IPv4Network and ipaddress.IPv6Network tuple construct https://bugs.python.org/issue36845 closed by inada.naoki #36875: argparse does not ship with translations https://bugs.python.org/issue36875 closed by terry.reedy #36883: 在ctypes里调用C库返回c_char_p类型时的问题 https://bugs.python.org/issue36883 closed by anthonypjshaw #36884: DeprecationWarning in test_asyncio.test_pep492.StreamReaderTes https://bugs.python.org/issue36884 closed by asvetlov #36886: Failed to construct CodeType on Python-3.8.0a4 https://bugs.python.org/issue36886 closed by SilentGhost #36899: datetime utcfromtimestamp ignores astimezone https://bugs.python.org/issue36899 closed by SilentGhost #36900: Use _PyCoreConfig rather than global configuration variables https://bugs.python.org/issue36900 closed by vstinner #36902: spam https://bugs.python.org/issue36902 closed by SilentGhost #36903: ResourceWarning in test_logging.HandlerTest.test_post_fork_chi https://bugs.python.org/issue36903 closed by xtreak #36909: LastUpdatedOrderedDict recipe uses super() unnecessarily https://bugs.python.org/issue36909 closed by rhettinger #36911: ast.parse outputs ast.Strs which do not differentiate between https://bugs.python.org/issue36911 closed by eric.smith #36912: Can't left-align strings using f-strings or format() https://bugs.python.org/issue36912 closed by gvanrossum #36914: zipimport does not load ZIP files produced by GitHub https://bugs.python.org/issue36914 closed by SilentGhost #36915: regrtest: when interrupted, temporary directory is not removed https://bugs.python.org/issue36915 closed by vstinner #36916: Swallow unhandled exception report introduced by 36802 https://bugs.python.org/issue36916 closed by asvetlov #36920: inspect.getcallargs sees optional arg to builtin as required https://bugs.python.org/issue36920 closed by brett.cannon #36923: Implemented __str__ for zip and map objects https://bugs.python.org/issue36923 closed by SilentGhost #36925: python3.7.3 can't work after MacOS upgrade from v10.14.4 to v1 https://bugs.python.org/issue36925 closed by ned.deily #36928: linkt threading.settrace to sys.settrace https://bugs.python.org/issue36928 closed by SilentGhost #36930: Windows proxy settings automatically used ... partly https://bugs.python.org/issue36930 closed by iwetzel #36931: json lib doesnt want to load from file https://bugs.python.org/issue36931 closed by zach.ware #36934: C API Function PyLong_AsDouble Returning Wrong Value https://bugs.python.org/issue36934 closed by sajjadfx #36938: Py_XDECREF on PyUnicodeobject raises SIGSEGV signal https://bugs.python.org/issue36938 closed by serhiy.storchaka #36939: Allow to use shutil.copytree for existing destination director https://bugs.python.org/issue36939 closed by jack1142 #1465646: test_grp & test_pwd fail https://bugs.python.org/issue1465646 closed by matrixise

1 0

bpo-36829: Add sys.unraisablehook()
by Victor Stinner 17 May '19

17 May '19

Hi, I recently modified Python 3.8 to start logging I/O error in io destructors when using the development mode (-X dev) or when Python is built in debug mode. This change allows to debug bpo-18748 very strange crash in PyThread_exit_thread(), when a thread closes an arbitrary file descriptor by mistake. The problem is that exceptions raised in a destructor cannot be passed to the current function call: the exception is logged into sys.stderr with a message like "Exception ignored in: ...". It's easy to miss such message in stderr. Thomas Grainger opened 36829 to propose to add -X abortunraisable command line option: abort immediately the current process (by calling Py_FatalError()) at the first PyErr_WriteUnraisable() call. Thomas had like a way to easily detect these in CI. I'm not satisfied by his proposal, since it only gives little control to the user on how "unraisable exceptions" are handled: the process dies, that's all. https://bugs.python.org/issue36829 I proposed a different approach: add a new sys.unraisablehook hook which is called to handle an "unraisable exception". To handle them differently, replace the hook. For example, I wrote a custom hook to log these exceptions into a file (the output on the Python test suite is interesting!). It also becomes trivial to reimplement Thomas's idea (kill the process): import signal def hook(unraisable): signal.raise_signal(signal.SIGABRT) sys.unraisablehook = hook I plan to merge my implementation soon, are you fine with that? https://github.com/python/cpython/pull/13187 -- The first implementation of my API used sys.unraisablehook(exc_type, exc_value, exc_tb, obj). The problem is that Serhiy Storchaka asked me to add a new error message field which breaks the API: the API is not future-proof. I modified my API to create an object to pack arguments. The new API becomes sys.unraisablehook(unraisable) where unraisable has 4 fields: exc_type, exc_value, exc_tb, obj. This API is now future-proof: adding a new field will not break existing custom hooks! By the way, I like this idea of adding an optional error message, and I plan to implement it once sys.unraisablehook is merged ;-) I already implemented it previously, but I reverted my changes to make the PR simpler to review. Extract of the documentation: """ Add new :func:`sys.unraisablehook` function which can be overriden to control how "unraisable exceptions" are handled. It is called when an exception has occurred but there is no way for Python to handle it. For example, when a destructor raises an exception or during garbage collection (:func:`gc.collect`). """ My implementation has a limitation: if PyErr_WriteUnraisable() is called after the Python finalization cleared sys attributes (almost the last function call of Py_Finalize), the default hook is called instead of the custom hook. In this case, sys.stderr is None and so the default hook does nothing. These late calls to PyErr_WriteUnraisable() cannot be catched with my approached, whereas Thomas Grainger's command line option "-X abortunraisable" allows that. My concern with Thomas's approach is that if the problem is killed with SIGABRT by such late PyErr_WriteUnraisable(), a low-level debugger like gdb is needed to investigate the crash, since Python is already finalized and so cannot be used to investigate. I prefer to allow arbitrary hook with the limitation, rather than always kill the process with SIGABRT at the first PyErr_WriteUnraisable() and require to use a low-level debugger. Victor -- Night gathers, and now my watch begins. It shall not end until my death.

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Need review
by Antoine Pitrou 16 May '19

16 May '19

Hello, I need a review on the PEP 574 implementation: https://github.com/python/cpython/pull/7076 I would really like it to be in 3.8 and so ideally it should be merged within two weeks. Regards Antoine.

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bpo-9584: Added brace expressions to the glob and fnmatch.
by matus valo 16 May '19

16 May '19

Hi All, I have implemented PR fixing bpo-9584 few months ago. Recently, I was encouraged that conversation on DEV mailing list should be started here on DEV mailing list. From the conversation in bug report, I understood that the main problem is that straightforward implementation can break a backward compatibility. E.g.: * Patched python: >>> import os >>> import glob >>> os.makedirs('a{b,c}d/e') >>> os.listdir('a{b,c}d') ['e'] >>> glob.glob('a{b,c}d/*') [] >>> * Unpatched python: >>> import os, glob >>> os.makedirs('a{b,c}d/e') >>> os.listdir('a{b,c}d') ['e'] >>> glob.glob('a{b,c}d/*') ['a{b,c}d/e'] How can I proceed with the PR? Please advise. Thanks, Matus Valo

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Python Language Summit 2019 blog posts
by Mariatta 15 May '19

15 May '19

If you have FOMO (fear of missing out) of Python Language Summit 2019, worry no more. We invited A. Jesse Jiryu Davis to cover for the language summit, and the blog posts are starting to appear in The PSF's official blog. Starts here: http://pyfound.blogspot.com/2019/05/the-2019-python-language-summit.html More links will be added as they become available. Currently available posts: - Russell Keith-Magee: Python On Other Platforms https://pyfound.blogspot.com/2019/05/russell-keith-magee-python-on-other.ht… - Paul Ganssle: Time Zones In The Standard Library https://pyfound.blogspot.com/2019/05/paul-ganssle-time-zones-in-standard.ht… Thank you Jesse for writing up these posts, and thanks to all language summit presenters and attendees. ᐧ

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