Mailman 3 February 2015 - Python-Dev

Prefixes and namespaces
by Serhiy Storchaka 21 Feb '15

21 Feb '15

/* Namespaces are one honking great idea -- let's do more of those! */ There are two ways to avoid name conflicts: prefixes and namespaces. Programming languages that lacks namespaces (such as C) need to use prefixes. For example: PROTOCOL_SSLv2, PROTOCOL_SSLv3, PROTOCOL_SSLv23. Python used the same prefixed names when reflect C constants to module level Python globals. But when convert integer constants to IntEnum, is it needed to preserve common prefix? Or may be we can drop it, because enum class name plays its role? class Protocol(IntEnum): PROTOCOL_SSLv2 = ... PROTOCOL_SSLv3 = ... PROTOCOL_SSLv23 = ... or class Protocol(IntEnum): SSLv2 = ... SSLv3 = ... SSLv23 = ... ? Protocol.PROTOCOL_SSLv2 or Protocol.SSLv2?

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Idea: __length_hint__ wrapper in itertools
by Carlos Pita 21 Feb '15

21 Feb '15

Hi all, python now supports the __length_hint__ method but not for every use case that could potentially benefit from it, v.g.: 1) Some common builtins like map don't set the hint. 2) Generators. 3) Application specific hints that, by definition, can't be predicted by a general strategy. I know 1 and 2 were discussed at some length in the past, but still there is no agreement about what to do with them. In the meantime, and because of 3, what do you think about adding a simple iterator wrapper to itertools which would allow to provide the hint by the user without any significant performance lost (__next__ in the wrapper could be just the original __next__). AFAIK there is no such thing in the standard library or anywhere else and it seems pretty easy to implement, although maybe I'm completely wrong. Say: hinted_iter = it.length_hint(iter, hint) Cheers -- Carlos

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PEP 441 - Improving Python ZIP Application Support
by Paul Moore 21 Feb '15

21 Feb '15

I'm looking at putting together a patch for CPython to implement PEP 441. In doing so, there are a few issues that I'd like to raise with the PEP. These are all to do with the supporting app "pyzaa" (IIRC, Nick proposed renaming this to "pyzapp", which I like, but it's not a big deal either way). 1. The PEP says that the application will warn if you try to add C extensions to the archive. In practice, this will be quite hard to do - extensions vary across platforms, and it's not only C extensions that won't work from an archive (consider a DLL with a pure-python ctypes wrapper). We could check the filenames for "known" extensions (maybe using importlib.machinery.EXTENSION_SUFFIXES, but that varies by platform) but I think that's going to be fragile. IMO, the costs aren't worth the benefits, and I'd like to remove this proposal and simply document that applications packed up with pyzaa need to be tested to ensure they work from a zipfile. 2. The option to compile Python source seems to me to be of limited use. It ties the archive to a particular Python version (more precisely, only one version gets the benefits of precompiled bytecode). It's also tricky to implement, particularly the option to compile an existing archive, because there standard library py_compile and compileall modules work on the filesystem, and for compiling files in an archive it would be better to build the bytecode in memory (no need to use tempfiles). I'd prefer to say that if users want to include bytecode, they can precompile on disk (using compileall) for as many versions as they want. FWIW, Daniel's standalone pyzaa program doesn't currently include either of the above features. As well as removing things, I'd like to add a programmable API for the utility. At the moment I only have a rough idea of how that would work, but I'm thinking of a PyZApp class, which can be created from a filename or an open stream (like a ZipFile object) and which has methods to set the shebang line, setting the main entry point, and adding files or directories. Does that need to go into the PEP or is it OK to review the API as part of the patch? I don't mind either way, but my normal coding process tends to be to fiddle with the API as I code it up and use it in the main app, so I'd normally leave documenting the final API till it's written... If the above seems like a reasonable plan, I'll work up a patch with the intention that it gets approved and implemented in time for 3.5. Paul

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[X-POST] GSoC 2015 ideas
by Kushal Das 21 Feb '15

21 Feb '15

Hi all, In case anyone wants to mentor a student for GSoC 2015, or have an idea on which students can work on during GSoC, please start putting them up in [1]. I am yet to get the edit access, I will put up the initial template text there. You can even send the idea as a reply to this thread. The template for the ideas is given below: == Project name == * '''Project description''': Make sure you have a high-level description that any student can understand, as well as deeper details * '''Skills''': programming languages? specific domain knowledge? * '''Difficulty level''': Easy/Intermediate/Hard classification (students ask for this info frequently to help them narrow down their choices) * '''Related Readings/Links''': was there a mailing list discussion about this topic? standards you want the students to read first? bugs/feature requests? * '''Potential mentors''': A list of mentors likely to be involved with this project, so students know who to look for on IRC/mailing lists if they have questions. (If you've had trouble with students overwhelming specific mentors, feel free to re-iterate here if students should contact the mailing list to reach all mentors.) [1] https://wiki.python.org/moin/SummerOfCode/2015/python-core Kushal -- Fedora Cloud Engineer CPython Core Developer Director Python Software Foundation http://kushaldas.in

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Summary of Python tracker Issues
by Python tracker 20 Feb '15

20 Feb '15

ACTIVITY SUMMARY (2015-02-13 - 2015-02-20) Python tracker at http://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 4770 (-20) closed 30484 (+54) total 35254 (+34) Open issues with patches: 2239 Issues opened (24) ================== #23018: Add version info to python http://bugs.python.org/issue23018 reopened by serhiy.storchaka #23460: Decimals do not obey ':g' exponential notation formatting rule http://bugs.python.org/issue23460 opened by ikelly #23462: All os.exec*e variants crash on Windows http://bugs.python.org/issue23462 opened by nicolaje #23464: Remove or deprecate JoinableQueue in asyncio docs http://bugs.python.org/issue23464 opened by emptysquare #23465: Implement PEP 486 - Make the Python Launcher aware of virtual http://bugs.python.org/issue23465 opened by pmoore #23466: PEP 461: Inconsistency between str and bytes formatting of int http://bugs.python.org/issue23466 opened by serhiy.storchaka #23467: Improve byte formatting compatibility between Py2 and Py3 http://bugs.python.org/issue23467 opened by serhiy.storchaka #23469: Delete Misc/*.wpr files http://bugs.python.org/issue23469 opened by berker.peksag #23470: OpenBSD buildbot uses wrong stdlib http://bugs.python.org/issue23470 opened by serhiy.storchaka #23471: 404 Not Found when downloading Python 3.4.3rc1 Documentation http://bugs.python.org/issue23471 opened by stringsonfire #23472: Setup locales on buildbots http://bugs.python.org/issue23472 opened by serhiy.storchaka #23476: SSL cert verify fail for "www.verisign.com" http://bugs.python.org/issue23476 opened by nagle #23477: Increase coverage for wsgiref module http://bugs.python.org/issue23477 opened by ashkop #23484: SemLock acquire() keyword arg 'blocking' is invalid http://bugs.python.org/issue23484 opened by td #23485: PEP 475: handle EINTR in the select and selectors module http://bugs.python.org/issue23485 opened by haypo #23486: Enum member lookup is 20x slower than normal class attribute l http://bugs.python.org/issue23486 opened by craigh #23487: argparse: add_subparsers 'action' broken http://bugs.python.org/issue23487 opened by derks #23488: Random objects twice as big as necessary on 64-bit builds http://bugs.python.org/issue23488 opened by rhettinger #23489: atexit handlers are not executed when using multiprocessing.Po http://bugs.python.org/issue23489 opened by juj #23490: allocation (and overwrite) of a 0 byte buffer http://bugs.python.org/issue23490 opened by pkt #23491: PEP 441 - Improving Python Zip Application Support http://bugs.python.org/issue23491 opened by pmoore #23492: Argument Clinic: improve generated parser for 1-argument funct http://bugs.python.org/issue23492 opened by serhiy.storchaka #23493: optimize sort_keys in json module by using operator.itemgetter http://bugs.python.org/issue23493 opened by wbolster #433028: SRE: (?flag:...) is not supported http://bugs.python.org/issue433028 reopened by serhiy.storchaka Most recent 15 issues with no replies (15) ========================================== #23493: optimize sort_keys in json module by using operator.itemgetter http://bugs.python.org/issue23493 #23492: Argument Clinic: improve generated parser for 1-argument funct http://bugs.python.org/issue23492 #23487: argparse: add_subparsers 'action' broken http://bugs.python.org/issue23487 #23485: PEP 475: handle EINTR in the select and selectors module http://bugs.python.org/issue23485 #23484: SemLock acquire() keyword arg 'blocking' is invalid http://bugs.python.org/issue23484 #23470: OpenBSD buildbot uses wrong stdlib http://bugs.python.org/issue23470 #23469: Delete Misc/*.wpr files http://bugs.python.org/issue23469 #23464: Remove or deprecate JoinableQueue in asyncio docs http://bugs.python.org/issue23464 #23459: Linux: expose the new execveat() syscall http://bugs.python.org/issue23459 #23456: asyncio: add missing @coroutine decorators http://bugs.python.org/issue23456 #23455: file iterator "deemed broken"; can resume after StopIteration http://bugs.python.org/issue23455 #23444: HCI Bluetooth socket bind error on an arm crosscompiled enviro http://bugs.python.org/issue23444 #23443: XMLRPCLIB Exception uses str not class or instance http://bugs.python.org/issue23443 #23436: xml.dom.minidom.Element.ownerDocument is hiden http://bugs.python.org/issue23436 #23423: XPath Support in ElementTree doc omission http://bugs.python.org/issue23423 Most recent 15 issues waiting for review (15) ============================================= #23492: Argument Clinic: improve generated parser for 1-argument funct http://bugs.python.org/issue23492 #23491: PEP 441 - Improving Python Zip Application Support http://bugs.python.org/issue23491 #23490: allocation (and overwrite) of a 0 byte buffer http://bugs.python.org/issue23490 #23488: Random objects twice as big as necessary on 64-bit builds http://bugs.python.org/issue23488 #23486: Enum member lookup is 20x slower than normal class attribute l http://bugs.python.org/issue23486 #23477: Increase coverage for wsgiref module http://bugs.python.org/issue23477 #23469: Delete Misc/*.wpr files http://bugs.python.org/issue23469 #23466: PEP 461: Inconsistency between str and bytes formatting of int http://bugs.python.org/issue23466 #23465: Implement PEP 486 - Make the Python Launcher aware of virtual http://bugs.python.org/issue23465 #23458: [2.7] random: make the file descriptor non-inheritable (on POS http://bugs.python.org/issue23458 #23456: asyncio: add missing @coroutine decorators http://bugs.python.org/issue23456 #23451: Deprecation warnings building 3.5 Visual Studio Windows 8.1 64 http://bugs.python.org/issue23451 #23444: HCI Bluetooth socket bind error on an arm crosscompiled enviro http://bugs.python.org/issue23444 #23441: rlcompleter: tab on empty prefix => insert spaces http://bugs.python.org/issue23441 #23440: Extend http.server.SimpleHTTPRequestHandler testing http://bugs.python.org/issue23440 Top 10 most discussed issues (10) ================================= #22107: tempfile module misinterprets access denied error on Windows http://bugs.python.org/issue22107 16 msgs #21998: asyncio: support fork http://bugs.python.org/issue21998 8 msgs #22928: HTTP header injection in urrlib2/urllib/httplib/http.client http://bugs.python.org/issue22928 8 msgs #23465: Implement PEP 486 - Make the Python Launcher aware of virtual http://bugs.python.org/issue23465 7 msgs #23486: Enum member lookup is 20x slower than normal class attribute l http://bugs.python.org/issue23486 7 msgs #21257: Document parse_headers function of http.client http://bugs.python.org/issue21257 6 msgs #3566: httplib persistent connections violate MUST in RFC2616 sec 8.1 http://bugs.python.org/issue3566 5 msgs #20699: Document that binary IO classes work with bytes-likes objects http://bugs.python.org/issue20699 5 msgs #23425: Windows getlocale unix-like with french, german, portuguese, s http://bugs.python.org/issue23425 5 msgs #23452: Build errors using VS Express 2013 in win32 mode http://bugs.python.org/issue23452 5 msgs Issues closed (53) ================== #4773: HTTPMessage not documented and has inconsistent API across Py2 http://bugs.python.org/issue4773 closed by berker.peksag #9099: multiprocessing/win32: WindowsError: [Error 0] Success on Pipe http://bugs.python.org/issue9099 closed by davin #9119: Python download page needs to mention crypto code in Windows i http://bugs.python.org/issue9119 closed by berker.peksag #9913: Misc/SpecialBuilds.txt is out of date http://bugs.python.org/issue9913 closed by belopolsky #12782: Multiple context expressions do not support parentheses for co http://bugs.python.org/issue12782 closed by barry #14559: (2.7.3 Regression) PC\8.0 directory can no longer be used to http://bugs.python.org/issue14559 closed by steve.dower #14672: Windows installer: add desktop shortcut(s) http://bugs.python.org/issue14672 closed by steve.dower #14910: argparse: disable abbreviation http://bugs.python.org/issue14910 closed by berker.peksag #16111: Python 2.7.3 Windows MSI installer installs the VC++ 9 dlls di http://bugs.python.org/issue16111 closed by loewis #16361: HTTPS/TLS Problem in Python 3.3 http://bugs.python.org/issue16361 closed by loewis #17033: RPM spec file has old config_binsuffix value http://bugs.python.org/issue17033 closed by benjamin.peterson #17753: test_zipfile: requires write access to test and email.test http://bugs.python.org/issue17753 closed by serhiy.storchaka #19105: pprint doesn't use all width http://bugs.python.org/issue19105 closed by serhiy.storchaka #19681: test_repr (test.test_functools.TestPartialC) failures http://bugs.python.org/issue19681 closed by serhiy.storchaka #19792: pathlib does not support symlink in Windows XP http://bugs.python.org/issue19792 closed by steve.dower #20833: scripts\pydocgui.pyw out of date http://bugs.python.org/issue20833 closed by berker.peksag #21548: pydoc -k IndexError on empty docstring http://bugs.python.org/issue21548 closed by berker.peksag #21849: Fix multiprocessing for non-ascii data http://bugs.python.org/issue21849 closed by serhiy.storchaka #21898: .hgignore: Missing ignores for Eclipse/pydev http://bugs.python.org/issue21898 closed by berker.peksag #22235: httplib: TypeError with file() object in ssl.py http://bugs.python.org/issue22235 closed by r.david.murray #22633: Memory disclosure/buffer overread via bug in Py_FrozenMain http://bugs.python.org/issue22633 closed by python-dev #22735: Fix various crashes exposed through mro() customization http://bugs.python.org/issue22735 closed by berker.peksag #22844: test_gdb failure on Debian Wheezy for Z http://bugs.python.org/issue22844 closed by serhiy.storchaka #22883: Get rid of references to PyInt in Py3 sources http://bugs.python.org/issue22883 closed by serhiy.storchaka #22885: Arbitrary code execution vulnerability due to unchecked eval() http://bugs.python.org/issue22885 closed by serhiy.storchaka #23096: Implementation-depended pickling floats with protocol 0 http://bugs.python.org/issue23096 closed by serhiy.storchaka #23146: Incosistency in pathlib between / and \ http://bugs.python.org/issue23146 closed by pitrou #23169: Reflect that PreReq and BuildPreReq are deprecated in the late http://bugs.python.org/issue23169 closed by benjamin.peterson #23233: TypeError in ./setup.py http://bugs.python.org/issue23233 closed by serhiy.storchaka #23239: SSL match_hostname does not accept IP Address http://bugs.python.org/issue23239 closed by pitrou #23408: Pickle tests use incorrect test data http://bugs.python.org/issue23408 closed by serhiy.storchaka #23410: Document more BaseHTTPRequestHandler attributes http://bugs.python.org/issue23410 closed by python-dev #23418: Keep http.server.__all__ up to date http://bugs.python.org/issue23418 closed by berker.peksag #23422: Clarify docs for importlib.import_module() http://bugs.python.org/issue23422 closed by brett.cannon #23424: Unicode character ends interactive session http://bugs.python.org/issue23424 closed by terry.reedy #23437: Make user scripts directory versioned on Windows http://bugs.python.org/issue23437 closed by python-dev #23439: Fixed http.client.__all__ and added a test http://bugs.python.org/issue23439 closed by berker.peksag #23442: http.client.REQUEST_HEADER_FIELDS_TOO_LARGE renamed in 3.5 http://bugs.python.org/issue23442 closed by berker.peksag #23446: Use PyMem_New instead of PyMem_Malloc http://bugs.python.org/issue23446 closed by serhiy.storchaka #23450: Possible loss of data warnings building 3.5 Visual Studio Wind http://bugs.python.org/issue23450 closed by serhiy.storchaka #23457: make test failures http://bugs.python.org/issue23457 closed by dcrs6000(a)gmail.com #23461: Building on windows modifies importlib.h http://bugs.python.org/issue23461 closed by steve.dower #23463: Incorrect behaviour when opening files containing colons on Wi http://bugs.python.org/issue23463 closed by tim.golden #23468: ISO 8601 datetime process http://bugs.python.org/issue23468 closed by belopolsky #23473: Allow namedtuple to be JSON encoded as dict http://bugs.python.org/issue23473 closed by serhiy.storchaka #23474: Enhance locale testing http://bugs.python.org/issue23474 closed by serhiy.storchaka #23475: asyncio: reference leak in test_close_kill_running() http://bugs.python.org/issue23475 closed by haypo #23478: A list arg with default value inside function got appended eac http://bugs.python.org/issue23478 closed by benjamin.peterson #23479: str.format() breaks object duck typing http://bugs.python.org/issue23479 closed by r.david.murray #23480: Minor typo http://bugs.python.org/issue23480 closed by SilentGhost #23481: SSL module should not offer RC4 based cipher suites for client http://bugs.python.org/issue23481 closed by python-dev #23482: sqlite3_d.dll is not included in installer http://bugs.python.org/issue23482 closed by python-dev #23483: python 2.7 builds using icc http://bugs.python.org/issue23483 closed by SilentGhost

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str(IntEnum)
by Demian Brecht 20 Feb '15

20 Feb '15

While working on a bug in the issue tracker, I came across something that I thought was a little odd around the behaviour of IntEnum. Should the behaviour of an instance of an IntEnum not be symmetric to an int where possible? For example: >>> class MyEnum(IntEnum): ... FOO = 1 ... >>> MyEnum.FOO == 1 True >>> MyEnum.FOO * 3 == 3 True >>> str(MyEnum.FOO) == str(1) False In my mind, the string representation here should be “1” and not the label. Was this simply an oversight of the specialized IntEnum implementation, or was there a concrete reason for this that I’m not seeing?

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Re: [Python-Dev] cpython: Improve struct cache locality by bring commonly accessed fields close together.
by Antoine Pitrou 20 Feb '15

20 Feb '15

On Fri, 20 Feb 2015 08:50:10 +0000 raymond.hettinger <python-checkins(a)python.org> wrote: > https://hg.python.org/cpython/rev/0ba4bcc0a7a6 > changeset: 94696:0ba4bcc0a7a6 > user: Raymond Hettinger <python(a)rcn.com> > date: Fri Feb 20 00:50:04 2015 -0800 > summary: > Improve struct cache locality by bring commonly accessed fields close together. > > files: > Modules/_randommodule.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > > diff --git a/Modules/_randommodule.c b/Modules/_randommodule.c > --- a/Modules/_randommodule.c > +++ b/Modules/_randommodule.c > @@ -78,8 +78,8 @@ > > typedef struct { > PyObject_HEAD > + int index; > unsigned long state[N]; > - int index; > } RandomObject; I may be missing something something, but I don't see how that improves cache locality. The index is only ever looked up when the state is also looked up, and since the state is used sequentially there are equal chances for the state lookup to be near the end rather than near the front. Regards Antoine.

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Python 3.4 RPM on AIX
by Blaxton 18 Feb '15

18 Feb '15

hi I am having problem building Python RPM on AIX and I think there are several bugs in Python .spec files. README file says download the bz2 version, but only gziped and xz version available from Python website so had to convert the .tgz file to bz2 and copy it over to SOURCES directory. %define config_binsuffix was set to 2.6 and not sure why it should be 2.6 when I am working on 3.4 version. had to change it to to pass the error. %define config_binsuffix none Misc/cheatsheet seems to be decommissioned in new version of Python but still in spec file so commented it. The last error that I am receiving and can't figure the resolution is belowwhy it won't create the required direcotory ?Processing files: python-devel-3.4.2-AIX71 File not found by glob: /var/opt/freeware/tmp/python-3.4.2-root/usr/include/python3.4/*.h File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/lib/python3.4/config PreReq: rpmlib(VersionedDependencies) <= 3.0.3-1 python = 3.4.2 Processing files: python-tools-3.4.2-AIX71 File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/bin/pydoc File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/bin/smtpd.py PreReq: rpmlib(VersionedDependencies) <= 3.0.3-1 python = 3.4.2-AIX71 running rpm -bl option to see missing files are below: rpm -bl /opt/freeware/src/packages/SPECS/python-3.4.spec Processing files: python-3.4.2-AIX71 File not found by glob: /var/opt/freeware/tmp/python-3.4.2-root/opt/freeware/man/man1/python.1* File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/include/python3.4 Processing files: python-devel-3.4.2-AIX71 File not found by glob: /var/opt/freeware/tmp/python-3.4.2-root/usr/include/python3.4/*.h File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/lib/python3.4/config PreReq: rpmlib(VersionedDependencies) <= 3.0.3-1 python = 3.4.2 Processing files: python-tools-3.4.2-AIX71 File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/bin/pydoc File not found: /var/opt/freeware/tmp/python-3.4.2-root/usr/bin/smtpd.py PreReq: rpmlib(VersionedDependencies) <= 3.0.3-1 python = 3.4.2-AIX71 Any idea as how I can fix this ?

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Re: [Python-Dev] [Python-checkins] cpython (3.4): Issue #23446: Use PyMem_New instead of PyMem_Malloc to avoid possible integer
by Stefan Krah 16 Feb '15

16 Feb '15

On Mon, Feb 16, 2015 at 11:35:52AM +0000, serhiy.storchaka wrote: > diff --git a/Modules/_testbuffer.c b/Modules/_testbuffer.c > --- a/Modules/_testbuffer.c > +++ b/Modules/_testbuffer.c > @@ -850,7 +850,7 @@ > Py_ssize_t *dest; > Py_ssize_t x, i; > > - dest = PyMem_Malloc(len * (sizeof *dest)); > + dest = PyMem_New(Py_ssize_t, len); > if (dest == NULL) { > PyErr_NoMemory(); > return NULL; This, too, was already protected by len == ndim <= 64. Stefan Krah

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PEP 370 - per-user scripts directory on Windows
by Paul Moore 16 Feb '15

16 Feb '15

tl;dr - Having a shared per-user scripts directory on Windows (%APPDATA%/Python/Scripts) causes a number of potential issues when users install the same package in multiple Python versions. I'd like to suggest that this be changed to a versioned directory (%APPDATA%/PythonXY/Scripts) to match all other Python directories on Windows. This issue originally started as a discussion on the pip tracker around making --user the default for pip. See https://github.com/pypa/pip/issues/1668 for details. However, because the user scripts directory is shared across all Python versions, this poses a number of issues: 1. If we "pip install" something like pytest, which version gets the name "py.test.exe" works on a "last install wins" basis, which is not ideal. 2. The above behaviour (and more generally the shared site scripts directory) does not respect the user's "Make this my default Python" choice from the installer, in potentially surprising ways. 3. Uninstalling a package which has been installed in 2 pythons will likely fail, because either the checksum of an installed script does not match what's in the RECORD file, or because a file that should be present has already been uninstalled via a different Python version [1]. I suggest that the per-user scripts directory should be versioned, in exactly the same way as every other Python-related directory on Windows. So we would have %APPDATA%\PythonXY\Scripts alongside %APPDATA%\PythonXY\site-packages. This is a familiar pattern for Windows users, and should not cause significant confusion. It would be good to get this added for Python 3.5, *before* making user installs the default (needed for 3.5 as the default install location for 3.5 will need admin privileges to write). Some additional points: 1. This is a Windows-specific proposal, because Unix has always had scripts installed in a common location (e.g., /usr/local/bin) and commonly-understood solutions already exist on that platform (versioned command names, python -m, system package management, etc). However, these solutions would be a significant change for Windows users. 2. Packages which recommend a user install specifically so that their commands are available regardless of which Python is on PATH would have to find an alternative solution. I doubt there are many such packages, but this should be considered. 3. This proposal does not affect the Python launcher for Windows. People using the launcher exclusively may be currently using "py -m pip" (or whatever) to launch applications, in which case the change of user script directory won't affect them. 4. I am not aware of any tools that rely on the location of the user scripts directory. Such scripts should be using sysconfig in any case. 5. The problems mentioned exist in current Python versions, but haven't been flagged up, presumably because very few people use the user install location - precisely because it's not the default in pip. Changing the pip default would cause more people to encounter the issues, but I don't propose backporting this change, as it's not a bug fix. If it becomes a major issue for pip users on older versions, we can either reconsider this, or pip can decide on its own workaround. Comments? If this is acceptable, I would be willing to prepare a patch for Python 3.5 implementing this. Paul [1] Checking of checksums is not currently implemented, AFAIK, but it is the purpose of the checksums in the RECORD file, and could be implemented in future versions of pip.

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