Mailman 3 October 2020 - Python-Dev

test_asyncio needs your love
by Victor Stinner 15 Oct '20

15 Oct '20

Hi, As a member of the Night's Watch, I'm fixing the CI in the darkness for you (*). Last weeks, I managed to fix most issues. But I decided to give up on test_asyncio failures. I no longer have the bandwidth to investigate these complex issues. (*) https://pythondev.readthedocs.io/ci.html I need your help to debug and fix the following test_asyncio issues. (1) "test_asyncio altered the execution environment" open for almost one year https://bugs.python.org/issue38912 (2) "asyncio: MultiLoopWatcher has a race condition (test_asyncio: test_close_kill_running() hangs on AMD64 RHEL7 Refleaks 3.x)" open for longer than one year https://bugs.python.org/issue38323 There are 8 more open issues which contain "test_asyncio" in their title, but these 2 are the ones causing most troubles on the CI. Victor -- Night gathers, and now my watch begins. It shall not end until my death.

3 2

Performance benchmarks for 3.9
by Pablo Galindo Salgado 15 Oct '20

15 Oct '20

Hi! I have updated the branch benchmarks in the pyperformance server and now they include 3.9. There are some benchmarks that are faster but on the other hand some benchmarks are substantially slower, pointing at a possible performance regression in 3.9 in some aspects. In particular some tests like "unpack sequence" are almost 20% slower. As there are some other tests were 3.9 is faster, is not fair to conclude that 3.9 is slower, but this is something we should look into in my opinion. You can check these benchmarks I am talking about by: * Go here: https://speed.python.org/comparison/ * In the left bar, select "lto-pgo latest in branch '3.9'" and "lto-pgo latest in branch '3.8'" * To better read the plot, I would recommend to select a "Normalization" to the 3.8 branch (this is in the top part of the page) and to check the "horizontal" checkbox. These benchmarks are very stable: I have executed them several times over the weekend yielding the same results and, more importantly, they are being executed on a server specially prepared to running reproducible benchmarks: CPU affinity, CPU isolation, CPU pinning for NUMA nodes, CPU frequency is fixed, CPU governor set to performance mode, IRQ affinity is disabled for the benchmarking CPU nodes...etc so you can trust these numbers. I kindly suggest for everyone interested in trying to improve the 3.9 (and master) performance, to review these benchmarks and try to identify the problems and fix them or to find what changes introduced the regressions in the first place. All benchmarks are the ones being executed by the pyperformance suite ( https://github.com/python/pyperformance) so you can execute them locally if you need to. --- On a related note, I am also working on the speed.python.org server to provide more automation and ideally some integrations with GitHub to detect performance regressions. For now, I have done the following: * Recompute benchmarks for all branches using the same version of pyperformance (except master) so they can be compared with each other. This can only be seen in the "Comparison" tab: https://speed.python.org/comparison/ * I am setting daily builds of the master branch so we can detect performance regressions with daily granularity. These daily builds will be located in the "Changes" and "Timeline" tabs ( https://speed.python.org/timeline/). * Once the daily builds are working as expected, I plan to work on trying to automatically comment or PRs or on bpo if we detect that a commit has introduced some notable performance regression. Regards from sunny London, Pablo Galindo Salgado.

9 19

Shutting down Import-SIG mailing list?
by Eric V. Smith 13 Oct '20

13 Oct '20

Would anyone care if Import-SIG was shut down? It gets a few spam emails per day that need to be cleaned up. It hasn't had any real messages for a couple of years. I think if the discussions were moved to python-dev it wouldn't be a noticeable increase in traffic. We'd want to keep it around for the archives, but not for new postings. I don't know what's involved in that from a technical perspective. Eric

3 3

Summary of Python tracker Issues
by Python tracker 09 Oct '20

09 Oct '20

ACTIVITY SUMMARY (2020-10-02 - 2020-10-09) 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 7690 ( +2) closed 46029 (+69) total 53719 (+71) Open issues with patches: 3126 Issues opened (42) ================== #41913: EnvBuilder.install_scripts should use explicit permissions https://bugs.python.org/issue41913 opened by Frederik Rietdijk #41914: test_pdb fails https://bugs.python.org/issue41914 opened by sumagnadas #41915: unittest.mock.create_autospec(Obj, instance=True) has self key https://bugs.python.org/issue41915 opened by ettang #41916: cxx pthread check is not overrideable https://bugs.python.org/issue41916 opened by virtuald #41918: exec fails to take locals into account when running list compr https://bugs.python.org/issue41918 opened by qpeter #41919: Modify test_codecs to use the new codecs.unregister() function https://bugs.python.org/issue41919 opened by shihai1991 #41921: REDoS in parseentities https://bugs.python.org/issue41921 opened by yetingli #41926: Unpredictable behavior when parsing xml. (xml.etree.ElementTre https://bugs.python.org/issue41926 opened by CyberCreator #41928: ZipFile does not supports Unicode Path Extra Field (0x7075) zi https://bugs.python.org/issue41928 opened by ivan.sorokin.tech #41929: Detect OEM code page for zip archives in ZipFile based on syst https://bugs.python.org/issue41929 opened by ivan.sorokin.tech #41930: Wrap sqlite3_serialize API in sqlite3 module https://bugs.python.org/issue41930 opened by Kerrick Staley #41932: Incorrect struct definition with bitfields https://bugs.python.org/issue41932 opened by berthin #41933: Wording of s * n in Common Sequence Operations is not optimal https://bugs.python.org/issue41933 opened by mdk #41938: concurrent.futures.wait calls len() on an possible iterable https://bugs.python.org/issue41938 opened by rohitkg98 #41940: AMD64 Debian root 3.x: tests fail because downloaded files sta https://bugs.python.org/issue41940 opened by vstinner #41943: unittest.assertLogs passes unexpectedly https://bugs.python.org/issue41943 opened by mrbean-bremen #41944: [security] Python testsuite calls eval() on content received v https://bugs.python.org/issue41944 opened by serhiy.storchaka #41945: http.cookies.SimpleCookie.parse error after [keys] https://bugs.python.org/issue41945 opened by xnovakj #41946: Add concrete examples to os.path documentation https://bugs.python.org/issue41946 opened by theacodes #41948: Runtime error while trying to use Python3.9 with virtualenv https://bugs.python.org/issue41948 opened by abhicantdraw #41949: Redefinition of HMAC functions prevents static linking https://bugs.python.org/issue41949 opened by indygreg #41950: Typo in Python 3.9 what's new page https://bugs.python.org/issue41950 opened by kigawas #41951: python-3.8.2.exe /uninstall /quiet fails with Exit code: 0x643 https://bugs.python.org/issue41951 opened by szheng #41954: [mock] Recursion on mocking inspect.isfunction https://bugs.python.org/issue41954 opened by stanislavlevin #41956: Regression in HTMLParser on malformed tags https://bugs.python.org/issue41956 opened by dan #41959: Doc/library/asyncio-policy.rst grammar error https://bugs.python.org/issue41959 opened by raulcd #41960: Add globalns and localns to the inspect.signature and inspect. https://bugs.python.org/issue41960 opened by BTaskaya #41961: Windows install failure "could not set file security" https://bugs.python.org/issue41961 opened by steve.dower #41962: Make threading._register_atexit public? https://bugs.python.org/issue41962 opened by Ben.Darnell #41963: ConfigParser: stripping of comments should be documented https://bugs.python.org/issue41963 opened by jugmac00 #41966: datetime.time issue with pickling in PyPy https://bugs.python.org/issue41966 opened by ddddaaaa #41967: Handle annotations in the parser to avoid the need for roundtr https://bugs.python.org/issue41967 opened by pablogsal #41969: ttk.RadioButtons mis-sized under Windows 10 UI Scaling, with d https://bugs.python.org/issue41969 opened by Athanasius #41971: multiple tests in test_tools fail since Python 3.9 https://bugs.python.org/issue41971 opened by felixonmars #41972: bytes.find consistently hangs in a particular scenario https://bugs.python.org/issue41972 opened by Zeturic #41973: Docs: TypedDict is now of type function instead of class https://bugs.python.org/issue41973 opened by gaborjbernat #41975: Textwrap to conform to https://www.unicode.org/reports/tr14/tr https://bugs.python.org/issue41975 opened by mdk #41977: ctypes array inside structure requires explicit garbage collec https://bugs.python.org/issue41977 opened by maxim.pichler #41980: Argparse documentation is slightly misleading https://bugs.python.org/issue41980 opened by ygingras #41981: Errors building python 3.9.0 from source on Centos 7 with GCC https://bugs.python.org/issue41981 opened by ftesser #41982: [Python 3.8] Wrong location flagged as syntax error https://bugs.python.org/issue41982 opened by iljah #41983: Missing Documentation AF_PACKET https://bugs.python.org/issue41983 opened by TheNuGuy Most recent 15 issues with no replies (15) ========================================== #41983: Missing Documentation AF_PACKET https://bugs.python.org/issue41983 #41980: Argparse documentation is slightly misleading https://bugs.python.org/issue41980 #41977: ctypes array inside structure requires explicit garbage collec https://bugs.python.org/issue41977 #41975: Textwrap to conform to https://www.unicode.org/reports/tr14/tr https://bugs.python.org/issue41975 #41969: ttk.RadioButtons mis-sized under Windows 10 UI Scaling, with d https://bugs.python.org/issue41969 #41962: Make threading._register_atexit public? https://bugs.python.org/issue41962 #41960: Add globalns and localns to the inspect.signature and inspect. https://bugs.python.org/issue41960 #41959: Doc/library/asyncio-policy.rst grammar error https://bugs.python.org/issue41959 #41956: Regression in HTMLParser on malformed tags https://bugs.python.org/issue41956 #41950: Typo in Python 3.9 what's new page https://bugs.python.org/issue41950 #41948: Runtime error while trying to use Python3.9 with virtualenv https://bugs.python.org/issue41948 #41946: Add concrete examples to os.path documentation https://bugs.python.org/issue41946 #41945: http.cookies.SimpleCookie.parse error after [keys] https://bugs.python.org/issue41945 #41943: unittest.assertLogs passes unexpectedly https://bugs.python.org/issue41943 #41938: concurrent.futures.wait calls len() on an possible iterable https://bugs.python.org/issue41938 Most recent 15 issues waiting for review (15) ============================================= #41972: bytes.find consistently hangs in a particular scenario https://bugs.python.org/issue41972 #41967: Handle annotations in the parser to avoid the need for roundtr https://bugs.python.org/issue41967 #41960: Add globalns and localns to the inspect.signature and inspect. https://bugs.python.org/issue41960 #41959: Doc/library/asyncio-policy.rst grammar error https://bugs.python.org/issue41959 #41950: Typo in Python 3.9 what's new page https://bugs.python.org/issue41950 #41944: [security] Python testsuite calls eval() on content received v https://bugs.python.org/issue41944 #41943: unittest.assertLogs passes unexpectedly https://bugs.python.org/issue41943 #41938: concurrent.futures.wait calls len() on an possible iterable https://bugs.python.org/issue41938 #41933: Wording of s * n in Common Sequence Operations is not optimal https://bugs.python.org/issue41933 #41919: Modify test_codecs to use the new codecs.unregister() function https://bugs.python.org/issue41919 #41916: cxx pthread check is not overrideable https://bugs.python.org/issue41916 #41907: Regression in IntFlag behaviour in f-string https://bugs.python.org/issue41907 #41902: Micro optimization for range.index if step is 1 https://bugs.python.org/issue41902 #41894: UnicodeDecodeError during load failure in non-UTF-8 locale https://bugs.python.org/issue41894 #41891: asyncio.wait_for does not wait for task/future to be completed https://bugs.python.org/issue41891 Top 10 most discussed issues (10) ================================= #41967: Handle annotations in the parser to avoid the need for roundtr https://bugs.python.org/issue41967 23 msgs #26680: Incorporating float.is_integer into Decimal https://bugs.python.org/issue26680 16 msgs #41944: [security] Python testsuite calls eval() on content received v https://bugs.python.org/issue41944 13 msgs #41972: bytes.find consistently hangs in a particular scenario https://bugs.python.org/issue41972 11 msgs #41490: Update bundled pip to 20.2.1 and setuptools to 49.2.1 https://bugs.python.org/issue41490 10 msgs #41894: UnicodeDecodeError during load failure in non-UTF-8 locale https://bugs.python.org/issue41894 10 msgs #41981: Errors building python 3.9.0 from source on Centos 7 with GCC https://bugs.python.org/issue41981 10 msgs #36534: tarfile: handling Windows (path) illegal characters in archive https://bugs.python.org/issue36534 7 msgs #7946: Convoy effect with I/O bound threads and New GIL https://bugs.python.org/issue7946 4 msgs #41877: Check against misspellings of assert etc. in mock https://bugs.python.org/issue41877 4 msgs Issues closed (66) ================== #23984: Documentation error: Descriptors https://bugs.python.org/issue23984 closed by rhettinger #26332: OSError: exception: access violation writing <...> (Windows 10 https://bugs.python.org/issue26332 closed by eryksun #30578: Misleading example in sys.set_coroutine_wrapper docs https://bugs.python.org/issue30578 closed by vstinner #32192: Provide importlib.util.lazy_import helper function https://bugs.python.org/issue32192 closed by brett.cannon #32222: pygettext doesn't extract docstrings for functions with type a https://bugs.python.org/issue32222 closed by methane #32922: dbm.open() encodes filename with default encoding rather than https://bugs.python.org/issue32922 closed by Josh Friend #33235: Better help text for dict.setdefault https://bugs.python.org/issue33235 closed by methane #33894: tempfile.tempdir cannot be unset https://bugs.python.org/issue33894 closed by eric.smith #34552: Clarify built-in types comparisons https://bugs.python.org/issue34552 closed by gvanrossum #35291: duplicate of memoryview from io.BufferedWriter leaks https://bugs.python.org/issue35291 closed by methane #35404: Document how to import _structure in email.message https://bugs.python.org/issue35404 closed by Mariatta #37456: FAQ says positional arguments aren't a thing https://bugs.python.org/issue37456 closed by pablogsal #38605: [typing] PEP 563: Postponed evaluation of annotations: enable https://bugs.python.org/issue38605 closed by gvanrossum #38914: Clarify wording for warning message when checking a package https://bugs.python.org/issue38914 closed by pablogsal #39450: unittest TestCase shortDescription does not strip whitespace https://bugs.python.org/issue39450 closed by chris.jerdonek #40202: Misleading grammatically of ValueError Message? https://bugs.python.org/issue40202 closed by ammar2 #40348: Programming FAQ about "What is delegation?": Fix typos https://bugs.python.org/issue40348 closed by rhettinger #40391: io.FileIO.mode doesn't comply with the docs https://bugs.python.org/issue40391 closed by serhiy.storchaka #40430: ast.Slice is no longer a subclass of ast.slice https://bugs.python.org/issue40430 closed by serhiy.storchaka #40564: Using zipfile.Path with several files prematurely closes zip https://bugs.python.org/issue40564 closed by jaraco #40833: Clarify docstring of Path.rename https://bugs.python.org/issue40833 closed by taleinat #41306: test_tk test_widgets.ScaleTest fails with Tk 8.6.10 https://bugs.python.org/issue41306 closed by pablogsal #41428: PEP 604 -- Allow writing union types as X | Y https://bugs.python.org/issue41428 closed by gvanrossum #41483: Do not acquire lock in MemoryHandler.flush() if no target defi https://bugs.python.org/issue41483 closed by vinay.sajip #41557: Upgrade Windows and macOS builds to use SQLite 3.33 https://bugs.python.org/issue41557 closed by erlendaasland #41584: Clarify documentation for binary arithmetic operation subclass https://bugs.python.org/issue41584 closed by brett.cannon #41826: test_peg_generator compilation warnings https://bugs.python.org/issue41826 closed by pablogsal #41840: [regression] symtable.Symbol.is_local() is no longer True for https://bugs.python.org/issue41840 closed by pablogsal #41867: Include options for timespec in docstrings of isoformat https://bugs.python.org/issue41867 closed by taleinat #41875: __builtin_unreachable error in gcc 4.4.5 https://bugs.python.org/issue41875 closed by lukasz.langa #41887: ast.literal_eval does not accept strings with leading whitespa https://bugs.python.org/issue41887 closed by gvanrossum #41892: use both "for in" and "ElementTree.remove" has a index bug https://bugs.python.org/issue41892 closed by scoder #41898: Any logging causes assertLogs to pass https://bugs.python.org/issue41898 closed by vinay.sajip #41900: XML C14N serialisation fails with default namespace https://bugs.python.org/issue41900 closed by scoder #41905: add update_abstractmethods function to update an ABC's abstrac https://bugs.python.org/issue41905 closed by gvanrossum #41909: Segfault on __getattr__ infinite recursion on certain attribut https://bugs.python.org/issue41909 closed by serhiy.storchaka #41912: Long generator chain causes segmentation fault https://bugs.python.org/issue41912 closed by terry.reedy #41917: Python 3.9rc2 fails to install matplotlib https://bugs.python.org/issue41917 closed by steve.dower #41920: Weird add operation of "0.2222 + 0.1111" https://bugs.python.org/issue41920 closed by steven.daprano #41922: Use PEP 590 vectorcall to speed up calls to reversed() https://bugs.python.org/issue41922 closed by corona10 #41923: Add PEP 613 typing.TypeAlias to the standard library https://bugs.python.org/issue41923 closed by gvanrossum #41924: TextWrap's wrap method throws unhelpful error on bytes object https://bugs.python.org/issue41924 closed by ThePokestarFan #41925: Lowercase path to python.exe in pip.exe from venv is throwing https://bugs.python.org/issue41925 closed by chris-tse #41927: Why is there no documentation in Russian? https://bugs.python.org/issue41927 closed by serhiy.storchaka #41931: Make dict(object) return its attribute __dict__ https://bugs.python.org/issue41931 closed by rhettinger #41934: Add `has` method to `pathlib.Path` class. https://bugs.python.org/issue41934 closed by hadialqattan #41935: Add binary operator! https://bugs.python.org/issue41935 closed by pablogsal #41936: Remove macros Py_ALLOW_RECURSION/Py_END_ALLOW_RECURSION https://bugs.python.org/issue41936 closed by serhiy.storchaka #41937: how to use cpython O& https://bugs.python.org/issue41937 closed by steven.daprano #41939: 3.9.0 test_site warning: "urllib.requests._opener was modified https://bugs.python.org/issue41939 closed by vstinner #41941: Py_Initialize affects the console https://bugs.python.org/issue41941 closed by vstinner #41942: Add if condition for 'for loop' https://bugs.python.org/issue41942 closed by chienpingtsung #41947: Tests When Building Python https://bugs.python.org/issue41947 closed by eric.smith #41952: sys.version has double space between month and date https://bugs.python.org/issue41952 closed by steve.dower #41953: Confusing error message of 50,*2 https://bugs.python.org/issue41953 closed by wyz23x2 #41955: Python Modules https://bugs.python.org/issue41955 closed by christian.heimes #41957: IDLE does not Transform Tabs into Spaces in Interactive Mode https://bugs.python.org/issue41957 closed by terry.reedy #41958: importlib has not util module https://bugs.python.org/issue41958 closed by serhiy.storchaka #41964: difflib SequenceMatcher get_matching_blocks returns non-matchi https://bugs.python.org/issue41964 closed by tim.peters #41965: distutils.spawn.find_executable() fails to find .py files on W https://bugs.python.org/issue41965 closed by steve.dower #41968: 3.9 IDLE documentation. https://bugs.python.org/issue41968 closed by terry.reedy #41970: test_lib2to3 fails since Python 3.9 https://bugs.python.org/issue41970 closed by pablogsal #41974: Remove complex.__float__, complex.__floordiv__, etc https://bugs.python.org/issue41974 closed by serhiy.storchaka #41976: ctypes.util.find_library fails with gcc 9 https://bugs.python.org/issue41976 closed by pablogsal #41978: numpy, scipy packages failed to install via pip - Windows 10 P https://bugs.python.org/issue41978 closed by christian.heimes #41979: PEG parser doesn't accept extended unpacking in with statement https://bugs.python.org/issue41979 closed by lys.nikolaou

1 0

Python Documentation, Python language improvement, and productive discussion
by Carol Willing 09 Oct '20

09 Oct '20

Hi folks, Earlier this year at the Python Language Summit, Ned Batchelder and I presented the concept of a Documentation Workgroup and a vision for the next few years: - Slidedeck https://speakerdeck.com/willingc/cpython-documentation-the-next-5-years - Blog post https://pyfound.blogspot.com/2020/04/cpython-documentation-next-5-years.html Due to some health issues that I have had the past few months, I haven't yet set up the workgroup. It's a priority of mine for July. We will have an open call for workgroup participants. There's a lot going on in the world with COVID19 that is impacting our lives directly and indirectly. I encourage the core development community to consider how what they share about their feelings on PEP8 may impact others. Clearly, this is an issue where it's unlikely that there will be universal agreement. As you consider additional posts about PEP8, I encourage you to think about whether your post improves the Python language before hitting Send. Stay safe as we all live together in a world facing unusual constraints due to COVID19. Warmly, Carol

8 7

Re: Farewell, Python 3.5
by Boris Orlov 09 Oct '20

09 Oct '20

Gg python 3.5, and hello world to python 4 !

1 0

PEP 617 -- New PEG parser for CPython
by Brett Lovgren 08 Oct '20

08 Oct '20

I have access to a small Amazon Web Services credit through the end of November 2020. I'd be happy to let your team use that credit in support of the fuzzing validation mentioned below. "(One area we have not explored extensively is rejection of all wrong programs. We have unit tests that check for a certain number of explicit rejections, but more work could be done, e.g. by using a fuzzer that inserts random subtle bugs into existing code. We're open to help in this area.)" https://www.python.org/dev/peps/pep-0617/#validation Sincerely, Brett

5 4

[RELEASE] Python 3.9.0 is now available, and you can already test 3.10.0a1!
by Łukasz Langa 08 Oct '20

08 Oct '20

On behalf of the Python development community and the Python 3.9 release team, I’m pleased to announce the availability of Python 3.9.0. Python 3.9.0 is the newest feature release of the Python language, and it contains many new features and optimizations. You can find Python 3.9.0 here: https://www.python.org/downloads/release/python-390/ <https://www.python.org/downloads/release/python-390/> Most third-party distributors of Python should be making 3.9.0 packages available soon. See the “What’s New in Python 3.9 <https://docs.python.org/release/3.9.0/whatsnew/3.9.html>” document for more information about features included in the 3.9 series. Detailed information about all changes made in 3.9.0 can be found in its change log <https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog>. Maintenance releases for the 3.9 series will follow at regular bi-monthly intervals starting in late November of 2020. OK, boring! Where is Python 4? Not so fast! The next release after 3.9 will be 3.10. It will be an incremental improvement over 3.9, just as 3.9 was over 3.8, and so on. In fact, our newest Release Manager, Pablo Galindo Salgado, prepared the first alpha release of what will become 3.10.0 a year from now. You can check it out here: https://www.python.org/downloads/release/python-3100a1/ <https://www.python.org/downloads/release/python-3100a1/> We hope you enjoy the new releases! Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organization contributions to the Python Software Foundation. https://www.python.org/psf/ <https://www.python.org/psf/> More resources Online Documentation <https://docs.python.org/3.9/> PEP 596 <https://www.python.org/dev/peps/pep-0596/>, 3.9 Release Schedule PEP 619 <https://www.python.org/dev/peps/pep-0619/>, 3.10 Release Schedule Report bugs at https://bugs.python.org <https://bugs.python.org/>. Help fund Python and its community <https://www.python.org/psf/donations/>. Your friendly release team, Ned Deily @nad <https://discuss.python.org/u/nad> Steve Dower @steve.dower <https://discuss.python.org/u/steve.dower> Pablo Galindo Salgado @pablogsal <https://discuss.python.org/u/pablogsal> Łukasz Langa @ambv <https://discuss.python.org/u/ambv>

3 3

Re: [Python-checkins] bpo-41944: No longer call eval() on content received via HTTP in the UnicodeNames tests (GH-22575)
by Walter Dörwald 07 Oct '20

07 Oct '20

On 6 Oct 2020, at 16:22, Florian Bruhin wrote: > https://github.com/python/cpython/commit/a8bf44d04915f7366d9f8dfbf84822ac37… > commit: a8bf44d04915f7366d9f8dfbf84822ac37a4bab3 > branch: master > author: Florian Bruhin <me(a)the-compiler.org> > committer: GitHub <noreply(a)github.com> > date: 2020-10-06T16:21:56+02:00 > summary: > > bpo-41944: No longer call eval() on content received via HTTP in the > UnicodeNames tests (GH-22575) > > Similarly to GH-22566, those tests called eval() on content received > via > HTTP in test_named_sequences_full. This likely isn't exploitable > because > unicodedata.lookup(seqname) is called before self.checkletter(seqname, > None) - thus any string which isn't a valid unicode character name > wouldn't ever reach the checkletter method. > > Still, it's probably better to be safe than sorry. > > files: > M Lib/test/test_ucn.py > [...] > # Helper that put all \N escapes inside eval'd raw strings, > # to make sure this script runs even if the compiler > # chokes on \N escapes > - res = eval(r'"\N{%s}"' % name) > + res = ast.literal_eval(r'"\N{%s}"' % name) > self.assertEqual(res, code) > return res It would be even simpler to use unicodedata.lookup() which returns the unicode character when passed the name of the character, e.g. >>> unicodedata.lookup("NO-BREAK SPACE") '\xa0' Servus, Walter

2 2

Do we still need a support of non-type objects in issubclass()?
by Serhiy Storchaka 06 Oct '20

06 Oct '20

issubclass() accept types (extension types and new-style classes), classic classes and arbitrary objects with the __bases__ attribute as its arguments. The latter was added in issue464992 [1] to support the Zope extension ExtensionClass. I tested the current code of ExtensionClass [2], and seems it does not need that special support. Tests are passed on modified master which uses tp_bases instead of dynamical look up of __bases__, ExtensionClass.ExtensionClass is a subclass of type and ExtensionClass.Base is an instance of type, the code does not have the __bases__ property and does not set the __bases__ attribute explicitly. On other hand, the code in the Python core has a non-zero maintenance cost. It was rewritten several times for 19 years, there is a gigantic comment larger that the current code explaining it (and it is slightly outdated), and there was several bugs related to it [3] [4]. Should we continue to support non-type objects with __bases__ in issubclass()? If no, can we remove their support in 3.10 (it would fix a crash in issue41909) or after passing a deprecation period? [1] https://bugs.python.org/issue464992 [2] https://github.com/zopefoundation/ExtensionClass [3] https://bugs.python.org/issue39382 [4] https://bugs.python.org/issue41909

5 8