Mailman 3 January 2018 - Python-Dev

Re: [Python-Dev] PEP 567 v2
by Victor Stinner 05 Jan '18

05 Jan '18

Currently, Context.get(var) returns None when "var in context" is false. That's surprising and different than var.get(), especially when var has a default value. Code: --- import contextvars name = contextvars.ContextVar('name', default='victor') context = contextvars.copy_context() print(name in context) print(context.get(name)) print(name.get()) --- Output: --- False None victor --- Context.get() must raise a lookup error by default if var is not in context. It should return the default argument if it's set, it's just that the default parameter must not have a default value (None). I'l fine that Context.get(default=None) and var.get() behaves differently (return None vs victor in my example) when var isn't set and var has a default value. Victor

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Summary of Python tracker Issues
by Python tracker 05 Jan '18

05 Jan '18

ACTIVITY SUMMARY (2017-12-29 - 2018-01-05) 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 6377 (+22) closed 37871 (+28) total 44248 (+50) Open issues with patches: 2479 Issues opened (37) ================== #15982: asyncore.dispatcher does not handle windows socket error code https://bugs.python.org/issue15982 reopened by vstinner #32448: subscriptable https://bugs.python.org/issue32448 opened by thehesiod #32449: MappingView must inherit from Collection instead of Sized https://bugs.python.org/issue32449 opened by yahya-abou-imran #32450: non-descriptive variable name https://bugs.python.org/issue32450 opened by Yuri Kanivetsky #32451: python -m venv activation issue when using cygwin on windows https://bugs.python.org/issue32451 opened by Kevin #32453: shutil.rmtree can have O(n^2) performance on large dirs https://bugs.python.org/issue32453 opened by nh2 #32454: Add socket.close(fd) function https://bugs.python.org/issue32454 opened by christian.heimes #32455: PyCompile_OpcodeStackEffect() and dis.stack_effect() are not p https://bugs.python.org/issue32455 opened by serhiy.storchaka #32456: PYTHONIOENCODING=undefined doesn't work in Python 3 https://bugs.python.org/issue32456 opened by serhiy.storchaka #32457: Windows Python cannot handle an early PATH entry containing ". https://bugs.python.org/issue32457 opened by Ray Donnelly #32458: test_asyncio failures on Windows https://bugs.python.org/issue32458 opened by pitrou #32459: Capsule API usage docs are incompatible with module reloading https://bugs.python.org/issue32459 opened by ncoghlan #32461: the first build after a change to Makefile.pre.in uses the old https://bugs.python.org/issue32461 opened by xdegaye #32462: mimetypes.guess_type() returns incorrectly formatted type https://bugs.python.org/issue32462 opened by csabella #32463: problems with shutil.py and os.get_terminal_size https://bugs.python.org/issue32463 opened by Dhruve #32464: raise NotImplemented vs return NotImplemented https://bugs.python.org/issue32464 opened by thatiparthy #32465: [urllib] proxy_bypass_registry - extra error handling required https://bugs.python.org/issue32465 opened by chansol kim #32466: Fix missing test coverage for fractions.Fraction.__new__ https://bugs.python.org/issue32466 opened by gphemsley #32467: dict_values isn't considered a Collection nor a Container https://bugs.python.org/issue32467 opened by yahya-abou-imran #32469: Generator and coroutine repr could be more helpful https://bugs.python.org/issue32469 opened by pitrou #32471: Add an UML class diagram to the collections.abc module documen https://bugs.python.org/issue32471 opened by yahya-abou-imran #32473: Readibility of ABCMeta._dump_registry() https://bugs.python.org/issue32473 opened by yahya-abou-imran #32475: Add ability to query number of buffered bytes available on buf https://bugs.python.org/issue32475 opened by kata198 #32476: Add concat functionality to ElementTree xpath find https://bugs.python.org/issue32476 opened by jjolly #32477: Move jumps optimization from the peepholer to the compiler https://bugs.python.org/issue32477 opened by serhiy.storchaka #32479: inconsistent ImportError message executing same import stateme https://bugs.python.org/issue32479 opened by xiang.zhang #32485: Multiprocessing dict sharing between forked processes https://bugs.python.org/issue32485 opened by André Neto #32486: tail optimization for 'yield from' https://bugs.python.org/issue32486 opened by Robert Smart #32489: Allow 'continue' in 'finally' clause https://bugs.python.org/issue32489 opened by serhiy.storchaka #32490: subprocess: duplicate filename in exception message https://bugs.python.org/issue32490 opened by jwilk #32491: base64.decode: linebreaks are not ignored https://bugs.python.org/issue32491 opened by gregory.p.smith #32492: C Fast path for namedtuple's property/itemgetter pair https://bugs.python.org/issue32492 opened by rhettinger #32493: UUID Module - FreeBSD build failure https://bugs.python.org/issue32493 opened by David Carlier #32494: interface to gdbm_count https://bugs.python.org/issue32494 opened by sam-s #32495: Adding Timer to multiprocessing https://bugs.python.org/issue32495 opened by jcrotts #32496: lib2to3 fails to parse a ** of a conditional expression https://bugs.python.org/issue32496 opened by gregory.p.smith #32497: datetime.strptime creates tz naive object from value containin https://bugs.python.org/issue32497 opened by akeeman Most recent 15 issues with no replies (15) ========================================== #32496: lib2to3 fails to parse a ** of a conditional expression https://bugs.python.org/issue32496 #32494: interface to gdbm_count https://bugs.python.org/issue32494 #32490: subprocess: duplicate filename in exception message https://bugs.python.org/issue32490 #32486: tail optimization for 'yield from' https://bugs.python.org/issue32486 #32476: Add concat functionality to ElementTree xpath find https://bugs.python.org/issue32476 #32473: Readibility of ABCMeta._dump_registry() https://bugs.python.org/issue32473 #32467: dict_values isn't considered a Collection nor a Container https://bugs.python.org/issue32467 #32465: [urllib] proxy_bypass_registry - extra error handling required https://bugs.python.org/issue32465 #32459: Capsule API usage docs are incompatible with module reloading https://bugs.python.org/issue32459 #32454: Add socket.close(fd) function https://bugs.python.org/issue32454 #32450: non-descriptive variable name https://bugs.python.org/issue32450 #32446: ResourceLoader.get_data() should accept a PathLike https://bugs.python.org/issue32446 #32436: Implement PEP 567 https://bugs.python.org/issue32436 #32433: Provide optimized HMAC digest https://bugs.python.org/issue32433 #32423: The Windows SDK version 10.0.15063.0 was not found https://bugs.python.org/issue32423 Most recent 15 issues waiting for review (15) ============================================= #32497: datetime.strptime creates tz naive object from value containin https://bugs.python.org/issue32497 #32492: C Fast path for namedtuple's property/itemgetter pair https://bugs.python.org/issue32492 #32477: Move jumps optimization from the peepholer to the compiler https://bugs.python.org/issue32477 #32476: Add concat functionality to ElementTree xpath find https://bugs.python.org/issue32476 #32475: Add ability to query number of buffered bytes available on buf https://bugs.python.org/issue32475 #32473: Readibility of ABCMeta._dump_registry() https://bugs.python.org/issue32473 #32469: Generator and coroutine repr could be more helpful https://bugs.python.org/issue32469 #32462: mimetypes.guess_type() returns incorrectly formatted type https://bugs.python.org/issue32462 #32461: the first build after a change to Makefile.pre.in uses the old https://bugs.python.org/issue32461 #32458: test_asyncio failures on Windows https://bugs.python.org/issue32458 #32454: Add socket.close(fd) function https://bugs.python.org/issue32454 #32449: MappingView must inherit from Collection instead of Sized https://bugs.python.org/issue32449 #32436: Implement PEP 567 https://bugs.python.org/issue32436 #32433: Provide optimized HMAC digest https://bugs.python.org/issue32433 #32431: Two bytes objects of zero length don't compare equal https://bugs.python.org/issue32431 Top 10 most discussed issues (10) ================================= #17611: Move unwinding of stack for "pseudo exceptions" from interpret https://bugs.python.org/issue17611 16 msgs #32453: shutil.rmtree can have O(n^2) performance on large dirs https://bugs.python.org/issue32453 10 msgs #32466: Fix missing test coverage for fractions.Fraction.__new__ https://bugs.python.org/issue32466 10 msgs #32449: MappingView must inherit from Collection instead of Sized https://bugs.python.org/issue32449 9 msgs #32346: Speed up slot lookup for class creation https://bugs.python.org/issue32346 7 msgs #32430: Simplify Modules/Setup{,.dist,.local} https://bugs.python.org/issue32430 7 msgs #25095: test_httpservers hangs since Python 3.5 https://bugs.python.org/issue25095 6 msgs #32428: dataclasses: make it an error to have initialized non-fields i https://bugs.python.org/issue32428 5 msgs #32455: PyCompile_OpcodeStackEffect() and dis.stack_effect() are not p https://bugs.python.org/issue32455 5 msgs #32477: Move jumps optimization from the peepholer to the compiler https://bugs.python.org/issue32477 5 msgs Issues closed (28) ================== #18035: telnetlib incorrectly assumes that select.error has an errno a https://bugs.python.org/issue18035 closed by gregory.p.smith #23749: asyncio missing wrap_socket (starttls) https://bugs.python.org/issue23749 closed by yselivanov #31699: Deadlocks in `concurrent.futures.ProcessPoolExecutor` with pic https://bugs.python.org/issue31699 closed by pitrou #31778: ast.literal_eval supports non-literals in Python 3 https://bugs.python.org/issue31778 closed by serhiy.storchaka #32211: Document the bug in re.findall() and re.finditer() in 2.7 and https://bugs.python.org/issue32211 closed by serhiy.storchaka #32308: Replace empty matches adjacent to a previous non-empty match i https://bugs.python.org/issue32308 closed by serhiy.storchaka #32390: AIX compile error with Modules/posixmodule.c: Function argumen https://bugs.python.org/issue32390 closed by xdegaye #32399: _uuidmodule.c cannot build on AIX - different typedefs of uuid https://bugs.python.org/issue32399 closed by pitrou #32418: Implement Server.get_loop() method https://bugs.python.org/issue32418 closed by asvetlov #32420: LookupError : unknown encoding : [0x7FF092395AD0] ANOMALY https://bugs.python.org/issue32420 closed by terry.reedy #32439: Clean up the code for compiling comparison expressions https://bugs.python.org/issue32439 closed by serhiy.storchaka #32441: os.dup2 should return the new fd https://bugs.python.org/issue32441 closed by benjamin.peterson #32445: Skip creating redundant wrapper functions in ExitStack.callbac https://bugs.python.org/issue32445 closed by ncoghlan #32447: IDLE shell won't open on Mac OS 10.13.1 https://bugs.python.org/issue32447 closed by ned.deily #32452: Brackets and Parentheses used in an ambiguous way https://bugs.python.org/issue32452 closed by r.david.murray #32460: don't use tentative declarations https://bugs.python.org/issue32460 closed by benjamin.peterson #32468: Frame repr should be more helpful https://bugs.python.org/issue32468 closed by pitrou #32470: Unexpected behavior of struct.pack https://bugs.python.org/issue32470 closed by benjamin.peterson #32472: Mention of __await__ missing in Coroutine Abstract Methods https://bugs.python.org/issue32472 closed by asvetlov #32474: argparse nargs should support string wrapped integers too https://bugs.python.org/issue32474 closed by r.david.murray #32478: Add tests for 'break' and 'return' inside 'finally' clause https://bugs.python.org/issue32478 closed by serhiy.storchaka #32480: czipfile installation failure https://bugs.python.org/issue32480 closed by ronaldoussoren #32481: Hitting the acute accent ´ button on a Danish keyboard causes https://bugs.python.org/issue32481 closed by ned.deily #32482: Improve tests for syntax and grammar in 2.7 https://bugs.python.org/issue32482 closed by serhiy.storchaka #32483: Misleading reflective behaviour due to PEP 3131 NFKC identifie https://bugs.python.org/issue32483 closed by benjamin.peterson #32484: ImportError for gdbm 1.14 https://bugs.python.org/issue32484 closed by benjamin.peterson #32487: assertRaises should return the "captured" exception https://bugs.python.org/issue32487 closed by r.david.murray #32488: Fatal error using pydoc https://bugs.python.org/issue32488 closed by ned.deily

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Re: [Python-Dev] PEP 567 v2
by Victor Stinner 05 Jan '18

05 Jan '18

You can only modify a context when it's the current context, so using ContextVar.set() in Context.run(). Victor Le 5 janv. 2018 11:42 AM, "Paul Moore" <p.f.moore(a)gmail.com> a écrit : On 4 January 2018 at 23:58, Guido van Rossum <guido(a)python.org> wrote: > On Thu, Jan 4, 2018 at 9:27 AM, Paul Moore <p.f.moore(a)gmail.com> wrote: >> >> On 4 January 2018 at 15:56, Guido van Rossum <guido(a)python.org> wrote: >> > It was get_context() in an earlier version of PEP 567. We changed it to >> > copy_context() believing that that would clarify that you get a clone >> > that >> > is unaffected by subsequent ContextVar.set() operations (which affect >> > the >> > *current* context rather than the copy you just got). >> >> Ah thanks. In which case, simply changing the emphasis to avoid the >> implication that Context objects are immutable (while that may be true >> in a technical/implementation sense, it's not really true in a design >> sense if ContextVar.set modifies the value of a variable in a context) >> is probably sufficient. > > > Do you have a specific proposal for a wording change? PEP 567 describes > Context as "a read-only mapping, implemented using an immutable dictionary." > This sounds all right to me -- "read-only" is weaker than "immutable". Maybe > the implementation should not be mentioned here? (The crux here is that a > given Context acts as a variable referencing an immutable dict -- but it may > reference different immutable dicts at different times.) I've been struggling to think of good alternative wordings (it's a case of "I'm not sure what you're trying to say, so I can't work out how you should say it", unfortunately). The best I can come up with is """ A Context is a mapping from ContextVar objects to their values. The Context itself exposes the Mapping interface, so cannot be modified directly - to modify the value associated with a variable you need to use the ContextVar.set() method. """ Does that explain things correctly? One thing I am sure of is that we should remove "implemented using an immutable dictionary" - it's an implementation detail, and adds nothing but confusion to mention it here. Paul _______________________________________________ Python-Dev mailing list Python-Dev(a)python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/ victor.stinner%40gmail.com

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Re: [Python-Dev] 'continue'/'break'/'return' inside 'finally' clause
by Neil Schemenauer 05 Jan '18

05 Jan '18

Serhiy Storchaka <storchaka(a)gmail.com> wrote: > Currently 'break' and 'return' are never used inside 'finally' > clause in the stdlib. See the _recv_bytes() function: Lib/multiprocessing/connection.py: 316 > I would want to see a third-party code that uses them. These are the only ones I found so far: ./gevent/src/gevent/libev/corecffi.py: 147 ./gevent/src/gevent/threadpool.py: 226 I have an AST walker script that finds them. Regards, Neil

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PEP 567 (contextvars) idea: really implement the current context
by Victor Stinner 05 Jan '18

05 Jan '18

Hi, It seems like many people, including myself, are confused by the lack of concrete current context in the PEP 567 (contextvars). But it isn't difficult to implement the current context (I implemented it, see below). It might have a *minor* impact on performance, but Context mapping API is supposed to only be used for introspection according to Yury. With contextvars.get_context(), it becomes possible to introspect the current context, rather than a copy, and it becomes even more obvious than a context is mutable ;-) vstinner@apu$ ./python >>> import contextvars >>> ctx=contextvars.get_context() >>> name=contextvars.ContextVar('name', default='victor') >>> print(list(ctx.items())) [] >>> name.set('yury') <Token object at 0x7f4cc71f8ad8> >>> print(list(ctx.items())) [(<ContextVar name='name' default='victor' at 0x7f4cc71f18d8>, 'yury')] With my changes, the running context remains up to date in Context.run(). Example: --- import contextvars name = contextvars.ContextVar('name', default='victor') def func(): name.set('yury') print(f"context[name]: {context.get(name)}") print(f"name in context: {name in context}") context = contextvars.copy_context() context.run(func) --- Output: --- context[name]: yury name in context: True --- Compare it to the output without my changes: --- context[name]: None name in context: False --- If we have contextvars.get_context(), maybe contextvars.copy_context() can be removed and add a new Context.copy() method instead: new_context = contextvars.get_context().copy() *** I implemented contextvars.get_context() which returns the current context: https://github.com/vstinner/cpython/commit/1e5ee71c15e2b1387c888d6eca2b08ef… from https://github.com/vstinner/cpython/commits/current_context I added a context thread local storage (TLS): class PyThreadState: context: Context # can be None context_data: _ContextData I modified Context mapping API to use the context variables from the current thread state if it's the current thread state. PyContext_Enter() now not only sets PyThreadState.context_data, but also PyThreadState.context to itself. Pseudo-code for Context.get(): --- class Context(collections.abc.Mapping): def __init__(self): self._data = _ContextData() def _get_data(self): ts : PyThreadState = PyThreadState_Get() if ts.context is self: return ts.context_data else: return self._data def get(self, var): # FIXME: implement default data = self._get_data() return data.get(var) --- And Context.run() is modified to set also the context TLS: --- def run(self, callable, *args, **kwargs): ts : PyThreadState = PyThreadState_Get() saved_context : Optional[Context] = ts.context # NEW saved_data : _ContextData = ts.context_data try: ts.context_data = self._data return callable(*args, **kwargs) finally: self._data = ts.context_data ts.context = saved_context # NEW ts.context_data = saved_data --- Victor

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Discussion about the proposed ignore_modules argument for traceback functions
by Dmitry Kazakov 04 Jan '18

04 Jan '18

Hello! I'd like to draw some attention to the feature(s) proposed in the issue 31299. https://bugs.python.org/issue31299 It's a dependency of the other issue, it still needs discussion, and it hasn't received any comments from committers since last September. Personally, I think that a general traceback cleaning facility proposed by Antoine should be accompanied by a similar non-destructive feature in a traceback module. If it's decided that the latter makes sense implementing, I'm willing to revive (and update) the PR I've closed earlier in time for the approaching Python 3.7 feature code cutoff. Cheers

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Possible bug in base64.decode: linebreaks are not ignored
by Oleg Sivokon 03 Jan '18

03 Jan '18

Hello, I've tried reading various RFCs around Base64 encoding, but I couldn't make the ends meet. Yet there is an inconsistency between base64.decodebytes() and base64.decode() in that how they handle linebreaks that were used to collate the encoded text. Below is an example of what I'm talking about: >>> import base64 >>> foo = base64.encodebytes(b'123456789') >>> foo b'MTIzNDU2Nzg5\n' >>> foo = b'MTIzND\n' + b'U2Nzg5\n' >>> foo b'MTIzND\nU2Nzg5\n' >>> base64.decodebytes(foo) b'123456789' >>> from io import BytesIO >>> bytes_in = BytesIO(foo) >>> bytes_out = BytesIO() >>> bytes_in.seek(0) 0 >>> base64.decode(bytes_in, bytes_out) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/somewhere/lib/python3.6/base64.py", line 512, in decode s = binascii.a2b_base64(line) binascii.Error: Incorrect padding >>> bytes_in = BytesIO(base64.encodebytes(b'123456789')) >>> bytes_in.seek(0) 0 >>> base64.decode(bytes_in, bytes_out) >>> bytes_out.getvalue() b'123456789' Obviously, I'd expect encodebytes() and encode both to either accept or to reject the same input. Thanks. Oleg PS. I couldn't register to the bug-tracker (never received an email confirmation, not even in a spam folder), this is why I'm sending it here. This communication and all information contained in or attached to it is confidential, intended solely for the addressee, may be legally privileged and is the intellectual property of one of the companies of NEX Group plc ("NEX") or third parties. If you are not the intended addressee or receive this message in error, please immediately delete all copies of it and notify the sender. We have taken precautions to minimise the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachments. We do not accept liability for any loss or damage caused by software viruses. NEX reserves the right to monitor all communications. We do not accept any legal responsibility for the content of communications, and no communication shall be considered legally binding. Furthermore, if the content of this communication is personal or unconnected with our business, we accept no liability or responsibility for it. NEX Group plc is a public limited company registered in England and Wales under number 10013770 and certain of its affiliates are authorised and regulated by regulatory authorities. For further regulatory information please see www.NEX.com.

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Re: [Python-Dev] PEP 567 v2
by Victor Stinner 03 Jan '18

03 Jan '18

Victor: > ContextVar would be simpler if the default would be mandatory as well :-) If we modify ContextVar to use None as the default value, the 'default' parameter of ContextVar.get() becomes useless, ContextVar.get() and context[var] behaviour becomes obvious. Token.MISSING could also be removed. Since it's not possible to delete a variable, would it be crazy to always initialize variables with a value, None by default? Decimal context is given as an example of contextvars user. Decimal already has a default context. I don't know numpy.errstate: would it make sense to initialize it to None? If someone really needs the crazy case of "uninitialized" variable, a custom "UNINITIALIZED = object()" can be used, no? With these proposed changes, there is no more need to worry if a variable is set or not. It's unclear to me if context.items() contains variables which weren't explicit set, and so are set to their default value. Same question for "var in context" test. If variables always have a value, I would expect that "var in context" is always true but I don't understand if it's technically possible to implement it or even if it makes sense :-) Maybe my whole proposed change doesn't make sense? Victor

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[ssl] The weird case of IDNA
by Christian Heimes 02 Jan '18

02 Jan '18

Hi, tl;dr This mail is about internationalized domain names and TLS/SSL. It doesn't concern you if you live in ASCII-land. Me and a couple of other developers like to change the ssl module in a backwards-incompatible way to fix IDN support for TLS/SSL. Simply speaking the IDNA standards (internationalized domain names for applications) describe how to encode non-ASCII domain names. The DNS system and X.509 certificates cannot handle non-ASCII host names. Any non-ASCII part of a hostname is punyencoded. For example the host name 'www.bücher.de' (books) is translated into 'www.xn--bcher-kva.de'. In IDNA terms, 'www.bücher.de' is called an IDN U-label (unicode) and 'www.xn--bcher-kva.de' an IDN A-label (ASCII). Please refer to the TR64 document [1] for more information. In a perfect world, it would be very simple. We'd only had one IDNA standard. However there are multiple standards that are incompatible with each other. The German TLD .de demands IDNA-2008 with UTS#46 compatibility mapping. The hostname 'www.straße.de' maps to 'www.xn--strae-oqa.de'. However in the older IDNA 2003 standard, 'www.straße.de' maps to 'www.strasse.de', but 'strasse.de' is a totally different domain! CPython has only support for IDNA 2003. It's less of an issue for the socket module. It only converts text to IDNA bytes on the way in. All functions support bytes and text. Since IDNA encoding does change ASCII and IDNA-encoded data is ASCII, it is also no problem to pass IDNA2008-encoded text or bytes to all socket functions. Example: >>> import socket >>> import idna # from PyPI >>> names = ['straße.de', b'strasse.de', idna.encode('straße.de'), idna.encode('straße.de').encode('ascii')] >>> for name in names: ... print(name, socket.getaddrinfo(name, None, socket.AF_INET, socket.SOCK_STREAM, 0, socket.AI_CANONNAME)[0][3:5]) ... straße.de ('strasse.de', ('89.31.143.1', 0)) b'strasse.de' ('strasse.de', ('89.31.143.1', 0)) b'xn--strae-oqa.de' ('xn--strae-oqa.de', ('81.169.145.78', 0)) xn--strae-oqa.de ('xn--strae-oqa.de', ('81.169.145.78', 0)) As you can see, 'straße.de' is canonicalized as 'strasse.de'. The IDNA 2008 encoded hostname maps to a different IP address. On the other hand ssl module is currently completely broken. It converts hostnames from bytes to text with 'idna' codec in some places, but not in all. The SSLSocket.server_hostname attribute and callback function SSLContext.set_servername_callback() are decoded as U-label. Certificate's common name and subject alternative name fields are not decoded and therefore A-labels. The *must* stay A-labels because hostname verification is only defined in terms of A-labels. We even had a security issue once, because partial wildcard like 'xn*.example.org' must not match IDN hosts like 'xn--bcher-kva.example.org'. In issue [2] and PR [3], we all agreed that the only sensible fix is to make 'SSLContext.server_hostname' an ASCII text A-label. But this is an backwards incompatible fix. On the other hand, IDNA is totally broken without the fix. Also in my opinion, PR [3] is not going far enough. Since we have to break backwards compatibility anyway, I'd like to modify SSLContext.set_servername_callback() at the same time. Questions: - Is everybody OK with breaking backwards compatibility? The risk is small. ASCII-only domains are not affected and IDNA users are broken anyway. - Should I only fix 3.7 or should we consider a backport to 3.6, too? Regards, Christian [1] https://www.unicode.org/reports/tr46/ [2] https://bugs.python.org/issue28414 [3] https://github.com/python/cpython/pull/3010

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