Library

• Issue #19227: Any re-seeding of the OpenSSL RNG on fork has been removed; this should be handled by OpenSSL itself or by the application.
• Issue #19435: Fix directory traversal attack on CGIHttpRequestHandler.

Tests

• Issue #18964: Fix test_tcl when run with Tcl/Tk versions < 8.5.

Build

• Issue #15663: Revert OS X installer built-in Tcl/Tk support for 3.3.3. Some third-party projects, such as Matplotlib and PIL/Pillow, depended on being able to build with Tcl and Tk frameworks in /Library/Frameworks.

Core and Builtins

• Issue #18603: Ensure that PyOS_mystricmp and PyOS_mystrnicmp are in the Python executable and not removed by the linker’s optimizer.
• Issue #19279: UTF-7 decoder no more produces illegal strings.
• Fix macro expansion of _PyErr_OCCURRED(), and make sure to use it in at least one place so as to avoid regressions.
• Issue #19014: memoryview.cast() is now allowed on zero-length views.
• Issue #19098: Prevent overflow in the compiler when the recursion limit is set absurdly high.
• Issue #18942: sys._debugmallocstats() output was damaged on Windows.
• Issue #18667: Add missing “HAVE_FCHOWNAT” symbol to posix._have_functions.
• Issue #18368: PyOS_StdioReadline() no longer leaks memory when realloc() fails.
• Issue #16741: Fix an error reporting in int().
• Issue #17899: Fix rare file descriptor leak in os.listdir().
• Issue #18552: Check return value of PyArena_AddPyObject() in obj2ast_object().
• Issue #18560: Fix potential NULL pointer dereference in sum().
• Issue #15905: Fix theoretical buffer overflow in handling of sys.argv[0], prefix and exec_prefix if the operation system does not obey MAXPATHLEN.
• Issue #18344: Fix potential ref-leaks in _bufferedreader_read_all().
• Issue #17872: Fix a segfault in marshal.load() when input stream returns more bytes than requested.
• Issue #18426: Fix NULL pointer dereference in C extension import when PyModule_GetDef() returns an error.
• Issue #18328: Reorder ops in PyThreadState_Delete*() functions. Now the tstate is first removed from TLS and then deallocated.
• Issue #18184: PyUnicode_FromFormat() and PyUnicode_FromFormatV() now raise OverflowError when an argument of %c format is out of range.
• Issue #18137: Detect integer overflow on precision in float.__format__() and complex.__format__().
• Issue #18183: Fix various unicode operations on strings with large unicode codepoints.
• Issue #18180: Fix ref leak in _PyImport_GetDynLoadWindows().
• Issue #18038: SyntaxError raised during compilation sources with illegal encoding now always contains an encoding name.
• Issue #17644: Fix a crash in str.format when curly braces are used in square brackets.
• Issue #17983: Raise a SyntaxError for a global __class__ statement in a class body.
• Issue #17927: Frame objects kept arguments alive if they had been copied into a cell, even if the cell was cleared.

Library

• Issue #19227: Try to fix deadlocks caused by re-seeding then OpenSSL pseudo-random number generator on fork().
• Issue #16037: HTTPMessage.readheaders() raises an HTTPException when more than 100 headers are read. Adapted from patch by Jyrki Pulliainen.
• Issue #16040: CVE-2013-1752: nntplib: Limit maximum line lengths to 2048 to prevent readline() calls from consuming too much memory. Patch by Jyrki Pulliainen.
• Issue #16041: CVE-2013-1752: poplib: Limit maximum line lengths to 2048 to prevent readline() calls from consuming too much memory. Patch by Jyrki Pulliainen.
• Issue #17997: Change behavior of ssl.match_hostname() to follow RFC 6125, for security reasons. It now doesn’t match multiple wildcards nor wildcards inside IDN fragments.
• Issue #16039: CVE-2013-1752: Change use of readline in imaplib module to limit line length. Patch by Emil Lind.
• Issue #19393: Fix symtable.symtable function to not be confused when there are functions or classes named “top”.
• Issue #19339: telnetlib module is now using time.monotonic() when available to compute timeout.
• Issue #19288: Fixed the “in” operator of dbm.gnu databases for string argument. Original patch by Arfrever Frehtes Taifersar Arahesis.
• Issue #19287: Fixed the “in” operator of dbm.ndbm databases for string argument. Original patch by Arfrever Frehtes Taifersar Arahesis.
• Issue #19327: Fixed the working of regular expressions with too big charset.
• Issue #19350: Increasing the test coverage of macurl2path. Patch by Colin Williams.
• Issue #19352: Fix unittest discovery when a module can be reached through several paths (e.g. under Debian/Ubuntu with virtualenv).
• Issue #15207: Fix mimetypes to read from correct part of Windows registry Original patch by Dave Chambers
• Issue #8964: fix platform._sys_version to handle IronPython 2.6+. Patch by Martin Matusiak.
• Issue #16038: CVE-2013-1752: ftplib: Limit amount of data read by limiting the call to readline(). Original patch by Michał Jastrzębski and Giampaolo Rodola.
• Issue #18235: Fix the sysconfig variables LDSHARED and BLDSHARED under AIX. Patch by David Edelsohn.
• Issue #19276: Fixed the wave module on 64-bit big-endian platforms.
• Issue #18776: atexit callbacks now display their full traceback when they raise an exception.
• Issue #17827: Add the missing documentation for codecs.encode and codecs.decode.
• Issue #18458: Prevent crashes with newer versions of libedit. Its readline emulation has changed from 0-based indexing to 1-based like gnu readline. Original patch by Ronald Oussoren.
• Issue #18919: If the close() method of a writer in the sunau or wave module failed, second invocation of close() and destructor no more raise an exception.
• Issue #19131: The aifc module now correctly reads and writes sampwidth of compressed streams.
• Issue #19158: a rare race in BoundedSemaphore could allow .release() too often.
• Issue #18037: 2to3 now escapes ‘u’ and ‘U’ in native strings.
• Issue #19137: The pprint module now correctly formats instances of set and frozenset subclasses.
• Issue #19092: contextlib.ExitStack now correctly reraises exceptions from the __exit__ callbacks of inner context managers (Patch by Hrvoje Nikšić)
• Issue #12641: Avoid passing “-mno-cygwin” to the mingw32 compiler, except when necessary. Patch by Oscar Benjamin.
• Issue #18594: The fast path for collections.Counter() was never taken due to an over-restrictive type check. And the fallback path did not implement the same algorithm as the pure python code.
• Properly initialize all fields of a SSL object after allocation.
• Issue #4366: Fix building extensions on all platforms when –enable-shared is used.
• Issue #18950: Fix miscellaneous bugs in the sunau module. Au_read.readframes() now updates current file position and reads correct number of frames from multichannel stream. Au_write.writeframesraw() now correctly updates current file position. Au_read.getnframes() now returns an integer (as in Python 2). Au_read and Au_write now correctly works with file object if start file position is not a zero.
• Issue #19053: ZipExtFile.read1() with non-zero argument no more returns empty bytes until end of data.
• Issue #19028: Fixed tkinter.Tkapp.merge() for non-string arguments.
• Issue #3015: Fixed tkinter with wantobject=False. Any Tcl command call returned empty string.
• Issue #18050: Fixed an incompatibility of the re module with Python 3.3.0 binaries.
• Issue #19037: The mailbox module now makes all changes to maildir files before moving them into place, to avoid race conditions with other programs that may be accessing the maildir directory.
• Issue #14984: On POSIX systems, when netrc is called without a filename argument (and therefore is reading the user’s $HOME/.netrc file), it now enforces the same security rules as typical ftp clients: the .netrc file must be owned by the user that owns the process and must not be readable by any other user.
• Issue #18873: The tokenize module now detects Python source code encoding only in comment lines.
• Issue #17324: Fix http.server’s request handling case on trailing ‘/’. Patch contributed by Vajrasky Kok.
• Issue #19018: The heapq.merge() function no longer suppresses IndexError in the underlying iterables.
• Issue #18784: The uuid module no more attempts to load libc via ctypes.CDLL, if all necessary functions are already found in libuuid. Patch by Evgeny Sologubov.
• Issue #18672: Fixed format specifiers for Py_ssize_t in debugging output in the _sre module.
• Issue #18830: inspect.getclasstree() no more produces duplicated entries even when input list contains duplicates.
• Issue #18909: Fix _tkinter.tkapp.interpaddr() on Windows 64-bit, don’t cast 64-bit pointer to long (32 bits).
• Issue #18876: The FileIO.mode attribute now better reflects the actual mode under which the file was opened. Patch by Erik Bray.
• Issue #18418: After fork(), reinit all threads states, not only active ones. Patch by A. Jesse Jiryu Davis.
• Issue #16611: http.cookie now correctly parses the ‘secure’ and ‘httponly’ cookie flags.
• Issue #11973: Fix a problem in kevent. The flags and fflags fields are now properly handled as unsigned.
• Issue #17702: On error, os.environb now removes suppress the except context when raising a new KeyError with the original key.
• Issue #18755: Fixed the loader used in imp to allow get_data() to be called multiple times.
• Issue #16809: Fixed some tkinter incompabilities with Tcl/Tk 8.6.
• Issue #16809: Tkinter’s splitlist() and split() methods now accept Tcl_Obj argument.
• Issue #18324: set_payload now correctly handles binary input. This also supersedes the previous fixes for #14360, #1717, and #16564.
• Issue #17119: Fixed integer overflows when processing large strings and tuples in the tkinter module.
• Issue #18747: Re-seed OpenSSL’s pseudo-random number generator after fork. A pthread_atfork() parent handler is used to seed the PRNG with pid, time and some stack data.
• Issue #8865: Concurrent invocation of select.poll.poll() now raises a RuntimeError exception. Patch by Christian Schubert.
• Issue #13461: Fix a crash in the TextIOWrapper.tell method on 64-bit platforms. Patch by Yogesh Chaudhari.
• Issue #18777: The ssl module now uses the new CRYPTO_THREADID API of OpenSSL 1.0.0+ instead of the deprecated CRYPTO id callback function.
• Issue #18768: Correct doc string of RAND_edg(). Patch by Vajrasky Kok.
• Issue #18178: Fix ctypes on BSD. dlmalloc.c was compiled twice which broke malloc weak symbols.
• Issue #18709: Fix CVE-2013-4238. The SSL module now handles NULL bytes inside subjectAltName correctly. Formerly the module has used OpenSSL’s GENERAL_NAME_print() function to get the string represention of ASN.1 strings for rfc822Name (email), dNSName (DNS) and uniformResourceIdentifier (URI).
• Issue #18756: Improve error reporting in os.urandom() when the failure is due to something else than /dev/urandom not existing (for example, exhausting the file descriptor limit).
• Issue #18405: Improve the entropy of crypt.mksalt().
• Issue #19151: Fix docstring and use of _get_supported_file_loaders() to reflect 2-tuples.
• Issue #18676: Change ‘positive’ to ‘non-negative’ in queue.py put and get docstrings and ValueError messages. Patch by Zhongyue Luo
• Issue #18681: Fix a NameError in imp.reload() (noticed by Weizhao Li).
• Issue #8112: xlmrpc.server’s DocXMLRPCServer server no longer raises an error if methods have annotations; it now correctly displays the annotations.
• Issue #17998: Fix an internal error in regular expression engine.
• Issue #17557: Fix os.getgroups() to work with the modified behavior of getgroups(2) on OS X 10.8. Original patch by Mateusz Lenik.
• Issue #18599: Fix name attribute of _sha1.sha1() object. It now returns ‘SHA1’ instead of ‘SHA’.
• Issue #18561: Skip name in ctypes’ _build_callargs() if name is NULL.
• Issue #18559: Fix NULL pointer dereference error in _pickle module
• Issue #18556: Check the return value of a PyUnicode_AsWideChar() call in ctypes’ U_set().
• Issue #18549: Eliminate dead code in socket_ntohl()
• Issue #18514: Fix unreachable Py_DECREF() call in PyCData_FromBaseObj()
• Issue #18513: Fix behaviour of cmath.rect w.r.t. signed zeros on OS X 10.8 + gcc.
• Issue #18480: Add missing call to PyType_Ready to the _elementtree extension.
• Issue #17778: Fix test discovery for test_multiprocessing. (Patch by Zachary Ware.)
• Issue #18431: The new email header parser now decodes RFC2047 encoded words in structured headers.
• Issue #18432: The sched module’s queue method was incorrectly returning an iterator instead of a list.
• Issue #18044: The new email header parser was mis-parsing encoded words where an encoded character immediately followed the ‘?’ that follows the CTE character, resulting in a decoding failure. They are now decoded correctly.
• Issue #18101: Tcl.split() now process strings nested in a tuple as it do with byte strings.
• Issue #17198: Fix a NameError in the dbm module. Patch by Valentina Mukhamedzhanova.
• Issue #18013: Fix cgi.FieldStorage to parse the W3C sample form.
• Issue #18347: ElementTree’s html serializer now preserves the case of closing tags.
• Issue #17261: Ensure multiprocessing’s proxies use proper address.
• Issue #18343: faulthandler.register() now keeps the previous signal handler when the function is called twice, so faulthandler.unregister() restores correctly the original signal handler.
• Issue #17097: Make multiprocessing ignore EINTR.
• Issue #18339: Negative ints keys in unpickler.memo dict no longer cause a segfault inside the _pickle C extension.
• Issue #18224: Removed pydoc script from created venv, as it causes problems on Windows and adds no value over and above python -m pydoc ...
• Issue #18155: The csv module now correctly handles csv files that use a delimter character that has a special meaning in regexes, instead of throwing an exception.
• Issue #14360: encode_quopri can now be successfully used as an encoder when constructing a MIMEApplication object.
• Issue #18135: ssl.SSLSocket.write() now raises an OverflowError if the input string in longer than 2 gigabytes, and ssl.SSLContext.load_cert_chain() raises a ValueError if the password is longer than 2 gigabytes. The ssl module does not support partial write.
• Issue #18248: Fix libffi build on AIX.
• Issue #18259: Declare sethostname in socketmodule.c for AIX
• Issue #18167: cgi.FieldStorage no longer fails to handle multipart/form-data when rn appears at end of 65535 bytes without other newlines.
• subprocess: Prevent a possible double close of parent pipe fds when the subprocess exec runs into an error. Prevent a regular multi-close of the /dev/null fd when any of stdin, stdout and stderr was set to DEVNULL.
• Issue #16102: Make uuid._netbios_getnode() work again on Python 3.
• Issue #18109: os.uname() now decodes fields from the locale encoding, and socket.gethostname() now decodes the hostname from the locale encoding, instead of using the UTF-8 encoding in strict mode.
• Issue #17403: urllib.parse.robotparser normalizes the urls before adding to ruleline. This helps in handling certain types invalid urls in a conservative manner.
• Issue #18025: Fixed a segfault in io.BufferedIOBase.readinto() when raw stream’s read() returns more bytes than requested.
• Issue #18011: base64.b32decode() now raises a binascii.Error if there are non-alphabet characters present in the input string to conform a docstring. Updated the module documentation.
• Issue #13772: Restored directory detection of targets in os.symlink on Windows, which was temporarily removed in Python 3.2.3 due to an incomplete implementation. The implementation now works even if the symlink is created in a location other than the current directory.
• Issue #16986: ElementTree now correctly parses a string input not only when an internal XML encoding is UTF-8 or US-ASCII.
• Issue #17812: Fixed quadratic complexity of base64.b32encode().
• Issue #17980: Fix possible abuse of ssl.match_hostname() for denial of service using certificates with many wildcards (CVE-2013-2099).
• Issue #17981: Closed socket on error in SysLogHandler.
• Fix typos in the multiprocessing module.
• Issue #17754: Make ctypes.util.find_library() independent of the locale.
• Issue #17968: Fix memory leak in os.listxattr().
• Issue #17269: Workaround for socket.getaddrinfo crash on MacOS X with port None or “0” and flags AI_NUMERICSERV.
• Issue #18698: Ensure imp.reload() returns the module out of sys.modules.
• Issue #18080: When building a C extension module on OS X, if the compiler is overriden with the CC environment variable, use the new compiler as the default for linking if LDSHARED is not also overriden. This restores Distutils behavior introduced in 3.2.3 and inadvertently dropped in 3.3.0.
• Issue #18113: Fixed a refcount leak in the curses.panel module’s set_userptr() method. Reported by Atsuo Ishimoto.
• Issue #18849: Fixed a Windows-specific tempfile bug where collision with an existing directory caused mkstemp and related APIs to fail instead of retrying. Report and fix by Vlad Shcherbina.
• Issue #19400: Prevent extension module build failures with Xcode 5 on OS X 10.8+ when using a universal Python that included a PPC architecture, such as with a python.org 32-bit-only binary installer.

C API

• Issue #18351: Fix various issues with a helper function in importlib used by PyImport_ExecCodeModuleWithPathnames() (and thus by extension PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx()).

IDLE

• Issue #18873: IDLE now detects Python source code encoding only in comment lines.
• Issue #18988: The “Tab” key now works when a word is already autocompleted.
• Issue #18489: Add tests for SearchEngine. Original patch by Phil Webster.
• Issue #18429: Format / Format Paragraph, now works when comment blocks are selected. As with text blocks, this works best when the selection only includes complete lines.
• Issue #18226: Add docstrings and unittests for FormatParagraph.py. Original patches by Todd Rovito and Phil Webster.
• Issue #18279: Format - Strip trailing whitespace no longer marks a file as changed when it has not been changed. This fix followed the addition of a test file originally written by Phil Webster (the issue’s main goal).
• Issue #7136: In the Idle File menu, “New Window” is renamed “New File”. Patch by Tal Einat, Roget Serwy, and Todd Rovito.
• Remove dead imports of imp.
• Issue #18196: Avoid displaying spurious SystemExit tracebacks.
• Issue #5492: Avoid traceback when exiting IDLE caused by a race condition.
• Issue #17511: Keep IDLE find dialog open after clicking “Find Next”. Original patch by Sarah K.
• Issue #18055: Move IDLE off of imp and on to importlib.
• Issue #15392: Create a unittest framework for IDLE. Initial patch by Rajagopalasarma Jayakrishnan. See Lib/idlelib/idle_test/README.txt for how to run Idle tests.
• Issue #14146: Highlight source line while debugging on Windows.
• Issue #17532: Always include Options menu for IDLE on OS X. Patch by Guilherme Simões.

Tests

• Issue #14407: Fix unittest test discovery in test_concurrent_futures.
• Issue #18919: Unified and extended tests for audio modules: aifc, sunau and wave.
• Issue #18952: Fix regression in support data downloads introduced when test.support was converted to a package. Regression noticed by Zachary Ware.
• Issue #12037: Fix test_email for desktop Windows.
• Issue #15507: test_subprocess’s test_send_signal could fail if the test runner were run in an environment where the process inherited an ignore setting for SIGINT. Restore the SIGINT handler to the desired KeyboardInterrupt raising one during that test.
• Issue #18792: Use “127.0.0.1” or ”::1” instead of “localhost” as much as possible, since “localhost” goes through a DNS lookup under recent Windows versions.
• Issue #1666318: Add a test that shutil.copytree() retains directory permissions. Patch by Catherine Devlin.
• Issue #18357: add tests for dictview set difference. Patch by Fraser Tweedale.
• Issue #18273: move the tests in Lib/test/json_tests to Lib/test/test_json and make them discoverable by unittest. Patch by Zachary Ware.
• Fix a fcntl test case on KFreeBSD, Debian #708653 (Petr Salinger).
• Issue #18396: Fix spurious test failure in test_signal on Windows when faulthandler is enabled (Patch by Jeremy Kloth)
• Issue #17046: Fix broken test_executable_without_cwd in test_subprocess.
• Issue #15415: Add new temp_dir() and change_cwd() context managers to test.support, and refactor temp_cwd() to use them. Patch by Chris Jerdonek.
• Issue #15494: test.support is now a package rather than a module (Initial patch by Indra Talip)
• Issue #17944: test_zipfile now discoverable and uses subclassing to generate tests for different compression types. Fixed a bug with skipping some tests due to use of exhausted iterators.
• Issue #18266: test_largefile now works with unittest test discovery and supports running only selected tests. Patch by Zachary Ware.
• Issue #17767: test_locale now works with unittest test discovery. Original patch by Zachary Ware.
• Issue #18375: Assume –randomize when –randseed is used for running the testsuite.
• Issue #11185: Fix test_wait4 under AIX. Patch by Sébastien Sablé.
• Issue #17691: test_univnewlines now works with unittest test discovery. Patch by Zachary Ware.
• Issue #18094: test_uuid no more reports skipped tests as passed.
• Issue #11995: test_pydoc doesn’t import all sys.path modules anymore.

Documentation

• Issue #19392: Document that imp.reload() now also requires __loader__ to be set on the module being reloaded.
• Issue #18758: Fixed and improved cross-references.
• Issue #18743: Fix references to non-existant “StringIO” module.
• Issue #18783: Removed existing mentions of Python long type in docstrings, error messages and comments.
• Issue #17701: Improving strftime documentation.
• Issue #18440: Clarify that hash() can truncate the value returned from an object’s custom __hash__() method.
• Issue #17953: Mention that you shouldn’t replace sys.modules and deleting key items will cause Python to not be happy.
• Issue #17844: Add links to encoders and decoders for bytes-to-bytes codecs.
• Issue #14097: improve the “introduction” page of the tutorial.
• Issue #17977: The documentation for the cadefault argument’s default value in urllib.request.urlopen() is fixed to match the code.

Tools/Demos

• Issue #18873: 2to3 and the findnocoding.py script now detect Python source code encoding only in comment lines.
• Issue #18817: Fix a resource warning in Lib/aifc.py demo.
• Issue #18439: Make patchcheck work on Windows for ACKS, NEWS.
• Issue #18448: Fix a typo in Tools/demo/eiffel.py.
• Issue #18457: Fixed saving of formulas and complex numbers in Tools/demo/ss1.py.
• Issue #18449: Make Tools/demo/ss1.py work again on Python 3. Patch by Févry Thibault.
• Issue #15239: Make mkstringprep.py work again on Python 3.
• Issue #12990: The “Python Launcher” on OSX could not launch python scripts that have paths that include wide characters.

Build

• Issue #19356: Avoid using a C variabled named “_self”, it’s a reserved word in some C compilers.
• Issue #19130: Correct PCbuild/readme.txt, Python 3.3 and 3.4 require VS 2010.
• Issue #16067: Add description into MSI file to replace installer’s temporary name.
• Issue #18256: Compilation fix for recent AIX releases. Patch by David Edelsohn.
• Issue #15172: Document NASM 2.10+ as requirement for building OpenSSL 1.0.1 on Windows.
• Issue #1584: Provide options to override default search paths for Tcl and Tk when building _tkinter.
• Issue #15663: Tcl/Tk 8.5.15 is now included with the OS X 10.6+ 64-bit/32-bit installer for 10.6+. It is no longer necessary to install a third-party version of Tcl/Tk 8.5 to work around the problems in the Apple-supplied Tcl/Tk 8.5 shipped in OS X 10.6 and later releases.
• Issue #19019: Change the OS X installer build script to use CFLAGS instead of OPT for special build options. By setting OPT, some compiler-specific options like -fwrapv were overridden and thus not used, which could result in broken interpreters when building with clang.

Core and Builtins

• Issue #17237: Fix crash in the ASCII decoder on m68k.
• Issue #17408: Avoid using an obsolete instance of the copyreg module when the interpreter is shutdown and then started again.
• Issue #17863: In the interactive console, don’t loop forever if the encoding can’t be fetched from stdin.
• Issue #17867: Raise an ImportError if __import__ is not found in __builtins__.
• Issue #17857: Prevent build failures with pre-3.5.0 versions of sqlite3, such as was shipped with Centos 5 and Mac OS X 10.4.
• Issue #17413: sys.settrace callbacks were being passed a string instead of an exception instance for the ‘value’ element of the arg tuple if the exception originated from C code; now an exception instance is always provided.
• Issue #17782: Fix undefined behaviour on platforms where struct timespec‘s “tv_nsec” member is not a C long.
• Issue #17715: Fix segmentation fault from raising an exception in a __trunc__ method.
• Issue #16447: Fixed potential segmentation fault when setting __name__ on a class.
• Issue #17669: Fix crash involving finalization of generators using yield from.
• Issue #17619: Make input() check for Ctrl-C correctly on Windows.
• Issue #17610: Don’t rely on non-standard behavior of the C qsort() function.
• Issue #17357: Add missing verbosity output when using -v/-vv.

Library

• Issue #17606: Fixed support of encoded byte strings in the XMLGenerator characters() and ignorableWhitespace() methods. Original patch by Sebastian Ortiz Vasquez.
• Issue #17732: Ignore distutils.cfg options pertaining to install paths if a virtual environment is active.
• Issue #1159051: Back out a fix for handling corrupted gzip files that broke backwards compatibility.
• Issue #17915: Fix interoperability of xml.sax with file objects returned by codecs.open().
• Issue #16601: Restarting iteration over tarfile no more continues from where it left off. Patch by Michael Birtwell.
• Issue #17289: The readline module now plays nicer with external modules or applications changing the rl_completer_word_break_characters global variable. Initial patch by Bradley Froehle.
• Issue #12181: select module: Fix struct kevent definition on OpenBSD 64-bit platforms. Patch by Federico Schwindt.
• Issue #14173: Avoid crashing when reading a signal handler during interpreter shutdown.
• Issue #16316: mimetypes now recognizes the .xz and .txz (.tar.xz) extensions.
• Issue #15902: Fix imp.load_module() accepting None as a file when loading an extension module.
• Issue #17802: Fix an UnboundLocalError in html.parser. Initial tests by Thomas Barlow.
• Issue #15535: Fix namedtuple pickles which were picking up the OrderedDict instead of just the underlying tuple.
• Issue #17192: Restore the patch for Issue #11729 which was ommitted in 3.3.1 when updating the bundled version of libffi used by ctypes. Update many libffi files that were missed in 3.3.1’s update to libffi-3.0.13.
• Issue #17358: Modules loaded by imp.load_source() and load_compiled() (and by extention load_module()) now have a better chance of working when reloaded.
• Issue #17353: Plistlib emitted empty data tags with deeply nested datastructures
• Issue #11714: Use ‘with’ statements to assure a Semaphore releases a condition variable. Original patch by Thomas Rachel.
• Issue #17795: Reverted backwards-incompatible change in SysLogHandler with Unix domain sockets.
• Issue #17555: Fix ForkAwareThreadLock so that size of after fork registry does not grow exponentially with generation of process.
• Issue #17707: multiprocessing.Queue’s get() method does not block for short timeouts.
• Isuse #17720: Fix the Python implementation of pickle.Unpickler to correctly process the APPENDS opcode when it is used on non-list objects.
• Issue #17012: shutil.which() no longer fallbacks to the PATH environment variable if empty path argument is specified. Patch by Serhiy Storchaka.
• Issue #17710: Fix pickle raising a SystemError on bogus input.
• Issue #17341: Include the invalid name in the error messages from re about invalid group names.
• Issue #17702: os.environ now raises KeyError with the original environment variable name (str on UNIX), instead of using the encoded name (bytes on UNIX).
• Issue #16163: Make the importlib based version of pkgutil.iter_importers work for submodules. Initial patch by Berker Peksag.
• Issue #16804: Fix a bug in the ‘site’ module that caused running ‘python -S -m site’ to incorrectly throw an exception.
• Issue #17016: Get rid of possible pointer wraparounds and integer overflows in the re module. Patch by Nickolai Zeldovich.
• Issue #16658: add missing return to HTTPConnection.send() Patch by Jeff Knupp.
• Issue #14971: unittest test discovery no longer gets confused when a function has a different __name__ than its name in the TestCase class dictionary.
• Issue #17678: Fix DeprecationWarning in the http/cookiejar.py by changing the usage of get_origin_req_host() to origin_req_host.
• Issue #17666: Fix reading gzip files with an extra field.
• Issue #17502: Process DEFAULT values in mock side_effect that returns iterator. Patch by Michael Foord.
• Issue #17572: Avoid chained exceptions while passing bad directives to time.strptime(). Initial patch by Claudiu Popa.
• Issue #17435: threading.Timer’s __init__ method no longer uses mutable default values for the args and kwargs parameters.
• Issue #17526: fix an IndexError raised while passing code without filename to inspect.findsource(). Initial patch by Tyler Doyle.
• Issue #16550: Update the opcode descriptions of pickletools to use unsigned integers where appropriate. Initial patch by Serhiy Storchaka.

IDLE

• Issue #17838: Allow sys.stdin to be reassigned.
• Issue #13495: Avoid loading the color delegator twice in IDLE.
• Issue #17798: Allow IDLE to edit new files when specified on command line.
• Issue #14735: Update IDLE docs to omit “Control-z on Windows”.
• Issue #17585: Fixed IDLE regression. Now closes when using exit() or quit().
• Issue #17657: Show full Tk version in IDLE’s about dialog. Patch by Todd Rovito.
• Issue #17613: Prevent traceback when removing syntax colorizer in IDLE.
• Issue #1207589: Backwards-compatibility patch for right-click menu in IDLE.
• Issue #16887: IDLE now accepts Cancel in tabify/untabify dialog box.
• Issue #17625: In IDLE, close the replace dialog after it is used.
• Issue #14254: IDLE now handles readline correctly across shell restarts.
• Issue #17614: IDLE no longer raises exception when quickly closing a file.
• Issue #6698: IDLE now opens just an editor window when configured to do so.
• Issue #8900: Using keyboard shortcuts in IDLE to open a file no longer raises an exception.
• Issue #6649: Fixed missing exit status in IDLE. Patch by Guilherme Polo.

Tests

• Issue #17833: Fix test_gdb failures seen on machines where debug symbols for glibc are available (seen on PPC64 Linux).
• Issue #7855: Add tests for ctypes/winreg for issues found in IronPython. Initial patch by Dino Viehland.
• Issue #17712: Fix test_gdb failures on Ubuntu 13.04.
• Issue #17835: Fix test_io when the default OS pipe buffer size is larger than one million bytes.
• Issue #17065: Use process-unique key for winreg tests to avoid failures if test is run multiple times in parallel (eg: on a buildbot host).
• Issue #12820: add tests for the xml.dom.minicompat module. Patch by John Chandler and Phil Connell.
• Issue #17790: test_set now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17789: test_random now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17779: test_osx_env now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17766: test_iterlen now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17690: test_time now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17692: test_sqlite now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17843: Removed bz2 test data file that was triggering false-positive virus warnings with certain antivirus software.

Documentation

• Issue #15940: Specify effect of locale on time functions.
• Issue #6696: add documentation for the Profile objects, and improve profile/cProfile docs. Patch by Tom Pinckney.
• Issue #17915: Fix interoperability of xml.sax with file objects returned by codecs.open().

Build

• Issue #17547: In configure, explicitly pass -Wformat for the benefit for GCC 4.8.
• Issue #17962: Build with OpenSSL 1.0.1e on Windows.

Build

• Issue #17550: Fix the –enable-profiling configure switch.

IDLE

• Issue #17625: In IDLE, close the replace dialog after it is used.

Core and Builtins

• Issue #17328: Fix possible refleak in dict.setdefault.
• Issue #17223: Fix PyUnicode_FromUnicode() for string of 1 character outside the range U+0000-U+10ffff.
• Issue #1692335: Move initial args assignment to BaseException.__new__ to help pickling of naive subclasses.
• Issue #17275: Corrected class name in init error messages of the C version of BufferedWriter and BufferedRandom.
• Issue #7963: Fixed misleading error message that issued when object is called without arguments.
• Issue #5308: Raise ValueError when marshalling too large object (a sequence with size >= 2**31), instead of producing illegal marshal data.
• Issue #12983: Bytes literals with invalid x escape now raise a SyntaxError and a full traceback including line number.
• Issue #17173: Remove uses of locale-dependent C functions (isalpha() etc.) in the interpreter.
• Issue #17137: When an Unicode string is resized, the internal wide character string (wstr) format is now cleared.
• Issue #17043: The unicode-internal decoder no longer read past the end of input buffer.
• Issue #17098: All modules now have __loader__ set even if they pre-exist the bootstrapping of importlib.
• Issue #16979: Fix error handling bugs in the unicode-escape-decode decoder.
• Issue #10156: In the interpreter’s initialization phase, unicode globals are now initialized dynamically as needed.
• Issue #16980: Fix processing of escaped non-ascii bytes in the unicode-escape-decode decoder.
• Issue #16975: Fix error handling bug in the escape-decode bytes decoder.
• Issue #14850: Now a charmap decoder treats U+FFFE as “undefined mapping” in any mapping, not only in a string.
• Issue #16730: importlib.machinery.FileFinder now no longers raises an exception when trying to populate its cache and it finds out the directory is unreadable or has turned into a file. Reported and diagnosed by David Pritchard.
• Issue #16906: Fix a logic error that prevented most static strings from being cleared.
• Issue #11461: Fix the incremental UTF-16 decoder. Original patch by Amaury Forgeot d’Arc.
• Issue #16856: Fix a segmentation fault from calling repr() on a dict with a key whose repr raise an exception.
• Issue #16367: Fix FileIO.readall() on Windows for files larger than 2 GB.
• Issue #16455: On FreeBSD and Solaris, if the locale is C, the ASCII/surrogateescape codec is now used, instead of the locale encoding, to decode the command line arguments. This change fixes inconsistencies with os.fsencode() and os.fsdecode() because these operating systems announces an ASCII locale encoding, whereas the ISO-8859-1 encoding is used in practice.
• Issue #16761: Calling int() with base argument only now raises TypeError.
• Issue #16759: Support the full DWORD (unsigned long) range in Reg2Py when retrieving a REG_DWORD value. This corrects functions like winreg.QueryValueEx that may have been returning truncated values.
• Issue #14420: Support the full DWORD (unsigned long) range in Py2Reg when passed a REG_DWORD value. Fixes OverflowError in winreg.SetValueEx.
• Issue #16597: In buffered and text IO, call close() on the underlying stream if invoking flush() fails.
• Issue #16722: In the bytes() constructor, try to call __bytes__ on the argument before __index__.
• Issue #16602: When a weakref’s target was part of a long deallocation chain, the object could remain reachable through its weakref even though its refcount had dropped to zero.
• Issue #16416: On Mac OS X, operating system data are now always encoded/decoded to/from UTF-8/surrogateescape, instead of the locale encoding (which may be ASCII if no locale environment variable is set), to avoid inconsistencies with os.fsencode() and os.fsdecode() functions which are already using UTF-8/surrogateescape.
• Issue #16588: Silence unused-but-set warnings in Python/thread_pthread
• Issue #16546: Fix: ast.YieldFrom argument is now mandatory.
• Issue #16514: Fix regression causing a traceback when sys.path[0] is None (actually, any non-string or non-bytes type).
• Issue #16306: Fix multiple error messages when unknown command line parameters where passed to the interpreter. Patch by Hieu Nguyen.
• Issue #16215: Fix potential double memory free in str.replace(). Patch by Serhiy Storchaka.
• Issue #16453: Fix equality testing of dead weakref objects.
• Issue #9535: Fix pending signals that have been received but not yet handled by Python to not persist after os.fork() in the child process.
• Issue #15001: fix segfault on “del sys.modules[‘__main__’]”. Patch by Victor Stinner.
• Issue #8271: the utf-8 decoder now outputs the correct number of U+FFFD characters when used with the ‘replace’ error handler on invalid utf-8 sequences. Patch by Serhiy Storchaka, tests by Ezio Melotti.
• Issue #5765: Apply a hard recursion limit in the compiler instead of blowing the stack and segfaulting. Initial patch by Andrea Griffini.
• Issue #16402: When slicing a range, fix shadowing of exceptions from __index__.
• Issue #16336: fix input checking in the surrogatepass error handler. Patch by Serhiy Storchaka.
• Issue #8401: assigning an int to a bytearray slice (e.g. b[3:4] = 5) now raises an error.
• Fix segfaults on setting __qualname__ on builtin types and attempting to delete it on any type.
• Issue #16345: Fix an infinite loop when fromkeys on a dict subclass received a nonempty dict from the constructor.
• Issue #16271: Fix strange bugs that resulted from __qualname__ appearing in a class’s __dict__ and on type.
• Issue #6074: Ensure cached bytecode files can always be updated by the user that created them, even when the source file is read-only.
• Issue #14783: Improve int() docstring and switch docstrings for str(), range(), and slice() to use multi-line signatures.
• Issue #16160: Subclass support now works for types.SimpleNamespace.
• Issue #15379: Fix passing of non-BMP characters as integers for the charmap decoder (already working as unicode strings). Patch by Serhiy Storchaka.
• Issue #15144: Fix possible integer overflow when handling pointers as integer values, by using Py_uintptr_t instead of size_t. Patch by Serhiy Storchaka.
• Issue #15965: Explicitly cast AT_FDCWD as (int). Required on Solaris 10 (which defines AT_FDCWD as 0xffd19553), harmless on other platforms.
• Issue #15839: Convert SystemErrors in super() to RuntimeErrors.
• Issue #15846: Fix SystemError which happened when using ast.parse() in an exception handler on code with syntax errors.
• Issue #15801: Make sure mappings passed to ‘%’ formatting are actually subscriptable.
• Issue #15111: __import__ should let ImportError propagate when a module that is imported as a side-effect of using fromlist tries to import a module that cannot be found.

Library

• Issue #17540: Added style to formatter configuration by dict.
• Issue #17536: Add to webbrowser’s browser list: www-browser, x-www-browser, iceweasel, iceape.
• Issue #17488: Change the subprocess.Popen bufsize parameter default value from unbuffered (0) to buffering (-1) to match the behavior existing code expects and match the behavior of the subprocess module in Python 2 to avoid introducing hard to track down bugs.
• Issue #17521: Corrected non-enabling of logger following two calls to fileConfig().
• Issue #17508: Corrected MemoryHandler configuration in dictConfig() where the target handler wasn’t configured first.
• Issue #17209: curses.window.get_wch() now handles correctly KeyboardInterrupt (CTRL+c).
• Issue #5713: smtplib now handles 421 (closing connection) error codes when sending mail by closing the socket and reporting the 421 error code via the exception appropriate to the command that received the error response.
• Issue #17192: Update the ctypes module’s libffi to v3.0.13. This specifically addresses a stack misalignment issue on x86 and issues on some more recent platforms.
• Issue #8862: Fixed curses cleanup when getkey is interrputed by a signal.
• Issue #17443: imaplib.IMAP4_stream was using the default unbuffered IO in subprocess, but the imap code assumes buffered IO. In Python2 this worked by accident. IMAP4_stream now explicitly uses buffered IO.
• Issue #17476: Fixed regression relative to Python2 in undocumented pydoc ‘allmethods’; it was missing unbound methods on the class.
• Issue #16880: Do not assume _imp.load_dynamic() is defined in the imp module.
• Issue #16389: Fixed a performance regression relative to Python 3.1 in the caching of compiled regular expressions.
• Issue #17431: Fix missing import of BytesFeedParser in email.parser.
• Issue #1285086: Get rid of the refcounting hack and speed up urllib.parse.unquote() and urllib.parse.unquote_to_bytes().
• Issue #17368: Fix an off-by-one error in the Python JSON decoder that caused a failure while decoding empty object literals when object_pairs_hook was specified.
• Issue #14645: The email generator classes now produce output using the specified linesep throughout. Previously if the prolog, epilog, or body were stored with a different linesep, that linesep was used. This fix corrects an RFC non-compliance issue with smtplib.send_message.
• Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.
• Issue #16962: Use getdents64 instead of the obsolete getdents syscall in the subprocess module on Linux.
• Issue #17018: Make Process.join() retry if os.waitpid() fails with EINTR.
• Issue #17223: array module: Fix a crasher when converting an array containing invalid characters (outside range [U+0000; U+10ffff]) to Unicode: repr(array), str(array) and array.tounicode(). Patch written by Manuel Jacob.
• Issue #14720: sqlite3: Convert datetime microseconds correctly. Patch by Lowe Thiderman.
• Issue #17225: JSON decoder now counts columns in the first line starting with 1, as in other lines.
• Issue #13700: Fix byte/string handling in imaplib authentication when an authobject is specified.
• Issue #13153: Tkinter functions now raise TclError instead of ValueError when a string argument contains non-BMP character.
• Issue #9669: Protect re against infinite loops on zero-width matching in non-greedy repeat. Patch by Matthew Barnett.
• Issue #13169: The maximal repetition number in a regular expression has been increased from 65534 to 2147483647 (on 32-bit platform) or 4294967294 (on 64-bit).
• Issue #17143: Fix a missing import in the trace module. Initial patch by Berker Peksag.
• Issue #16743: Fix mmap overflow check on 32 bit Windows.
• Issue #16800: tempfile.gettempdir() no longer left temporary files when the disk is full. Original patch by Amir Szekely.
• Issue #16564: Fixed regression relative to Python2 in the operation of email.encoders.encode_7or8bit when used with binary data.
• Issue #17052: unittest discovery should use self.testLoader.
• Issue #4591: Uid and gid values larger than 2**31 are supported now.
• Issue #17141: random.vonmisesvariate() no more hangs for large kappas.
• Issue #17149: Fix random.vonmisesvariate to always return results in [0, 2*math.pi].
• Issue #1470548: XMLGenerator now works with binary output streams.
• Issue #6975: os.path.realpath() now correctly resolves multiple nested symlinks on POSIX platforms.
• Issue #16564: Fixed regression relative to Python2 in the operation of email.encoders.encode_noop when used with binary data.
• Issue #10355: In SpooledTemporaryFile class mode, name, encoding and newlines properties now work for unrolled files. Obsoleted and never working on Python 3 xreadline method now removed.
• Issue #16686: Fixed a lot of bugs in audioop module. Fixed crashes in avgpp(), maxpp() and ratecv(). Fixed an integer overflow in add(), bias(), and ratecv(). reverse(), lin2lin() and ratecv() no more lose precision for 32-bit samples. max() and rms() no more returns a negative result and various other functions now work correctly with 32-bit sample -0x80000000.
• Issue #17073: Fix some integer overflows in sqlite3 module.
• Issue #16723: httplib.HTTPResponse no longer marked closed when the connection is automatically closed.
• Issue #16948: Fix quoted printable body encoding for non-latin1 character sets in the email package.
• Issue #16811: Fix folding of headers with no value in the provisional email policies.
• Issue #17132: Update symbol for “yield from” grammar changes.
• Issue #17076: Make copying of xattrs more permissive of missing FS support. Patch by Thomas Wouters.
• Issue #17089: Expat parser now correctly works with string input not only when an internal XML encoding is UTF-8 or US-ASCII. It now accepts bytes and strings larger than 2 GiB.
• Issue #6083: Fix multiple segmentation faults occured when PyArg_ParseTuple parses nested mutating sequence.
• Issue #5289: Fix ctypes.util.find_library on Solaris.
• Issue #17106: Fix a segmentation fault in io.TextIOWrapper when an underlying stream or a decoder produces data of an unexpected type (i.e. when io.TextIOWrapper initialized with text stream or use bytes-to-bytes codec).
• Issue #15633: httplib.HTTPResponse is now mark closed when the server sends less than the advertised Content-Length.
• Issue #12268: The io module file object write methods no longer abort early when one of its write system calls is interrupted (EINTR).
• Issue #6972: The zipfile module no longer overwrites files outside of its destination path when extracting malicious zip files.
• Issue #4844: ZipFile now raises BadZipFile when opens a ZIP file with an incomplete “End of Central Directory” record. Original patch by Guilherme Polo and Alan McIntyre.
• Issue #17071: Signature.bind() now works when one of the keyword arguments is named self.
• Issue #12004: Fix an internal error in PyZipFile when writing an invalid Python file. Patch by Ben Morgan.
• Issue #1602133: on Mac OS X a shared library build (--enable-shared) now fills the os.environ variable correctly.
• Issue #15505: unittest.installHandler no longer assumes SIGINT handler is set to a callable object.
• Issue #13454: Fix a crash when deleting an iterator created by itertools.tee() if all other iterators were very advanced before.
• Issue #12411: Fix to cgi.parse_multipart to correctly use bytes boundaries and bytes data. Patch by Jonas Wagner.
• Issue #16957: shutil.which() no longer searches a bare file name in the current directory on Unix and no longer searches a relative file path with a directory part in PATH directories. Patch by Thomas Kluyver.
• Issue #16993: shutil.which() now preserves the case of the path and extension on Windows.
• Issue #16992: On Windows in signal.set_wakeup_fd, validate the file descriptor argument.
• Issue #16422: For compatibility with the Python version, the C version of decimal now uses strings instead of integers for rounding mode constants.
• Issue #15861: tkinter now correctly works with lists and tuples containing strings with whitespaces, backslashes or unbalanced braces.
• Issue #10527: Use poll() instead of select() for multiprocessing pipes.
• Issue #9720: zipfile now writes correct local headers for files larger than 4 GiB.
• Issue #16955: Fix the poll() method for multiprocessing’s socket connections on Windows.
• SSLContext.load_dh_params() now properly closes the input file.
• Issue #16900: Issue a ResourceWarning when an ssl socket is left unclosed.
• Issue #13899: A, Z, and B now correctly match the A, Z, and B literals when used inside character classes (e.g. ‘[A]’). Patch by Matthew Barnett.
• Issue #15545: Fix regression in sqlite3’s iterdump method where it was failing if the connection used a row factory (such as sqlite3.Row) that produced unsortable objects. (Regression was introduced by fix for 9750).
• Issue #15972: Fix error messages when os functions expecting a file name or file descriptor receive the incorrect type.
• Issue #16828: Fix error incorrectly raised by bz2.compress(b’‘) and bz2.BZ2Compressor.compress(b’‘). Initial patch by Martin Packman.
• Issue #16541: tk_setPalette() now works with keyword arguments.
• Issue #16820: In configparser, parser.popitem() no longer raises ValueError. This makes parser.clean() work correctly.
• Issue #16820: In configparser, parser['section'] = {} now preserves section order within the parser. This makes parser.update() preserve section order as well.
• Issue #16820: In configparser, parser['DEFAULT'] = {} now correctly clears previous values stored in the default section. Same goes for parser.update({'DEFAULT': {}}).
• Issue #9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.
• Issue #10527: make multiprocessing use poll() instead of select() if available.
• Issue #16688: Now regexes contained backreferences correctly work with non-ASCII strings. Patch by Matthew Barnett.
• Issue #16485: Now file descriptors are closed if file header patching failed on closing an aifc file.
• Issue #16165: sched.scheduler.run() no longer blocks a scheduler for other threads.
• Issue #16641: Default values of sched.scheduler.enter() are no longer modifiable.
• Issue #16618: Make glob.glob match consistently across strings and bytes regarding leading dots. Patch by Serhiy Storchaka.
• Issue #16713: Parsing of ‘tel’ urls using urlparse separates params from path.
• Issue #16443: Add docstrings to regular expression match objects. Patch by Anton Kasyanov.
• Issue #15701: Fix HTTPError info method call to return the headers information.
• Issue #16752: Add a missing import to modulefinder. Patch by Berker Peksag.
• Issue #16646: ftplib.FTP.makeport() might lose socket error details. (patch by Serhiy Storchaka)
• Issue #16626: Fix infinite recursion in glob.glob() on Windows when the pattern contains a wildcard in the drive or UNC path. Patch by Serhiy Storchaka.
• Issue #15783: Except for the number methods, the C version of decimal now supports all None default values present in decimal.py. These values were largely undocumented.
• Issue #16298: In HTTPResponse.read(), close the socket when there is no Content-Length and the incoming stream is finished. Patch by Eran Rundstein.
• Issue #15872: Fix 3.3 regression introduced by the new fd-based shutil.rmtree that caused it to not ignore certain errors when ignore_errors was set. Patch by Alessandro Moura and Serhiy Storchaka.
• Issue #16248: Disable code execution from the user’s home directory by tkinter when the -E flag is passed to Python. Patch by Zachary Ware.
• Issue #16628: Fix a memory leak in ctypes.resize().
• Issue #13614: Fix setup.py register failure with invalid rst in description. Patch by Julien Courteau and Pierre Paul Lefebvre.
• Issue #13512: Create ~/.pypirc securely (CVE-2011-4944). Initial patch by Philip Jenvey, tested by Mageia and Debian.
• Issue #7719: Make distutils ignore .nfs* files instead of choking later on. Initial patch by SilentGhost and Jeff Ramnani.
• Issue #13120: Allow to call pdb.set_trace() from thread. Patch by Ilya Sandler.
• Issue #16585: Make CJK encoders support error handlers that return bytes per PEP 383.
• Issue #10182: The re module doesn’t truncate indices to 32 bits anymore. Patch by Serhiy Storchaka.
• Issue #16573: In 2to3, treat enumerate() like a consuming call, so superfluous list() calls aren’t added to filter(), map(), and zip() which are directly passed enumerate().
• Issue #12848: The pure Python pickle implementation now treats object lengths as unsigned 32-bit integers, like the C implementation does. Patch by Serhiy Storchaka.
• Issue #16408: Fix file descriptors not being closed in error conditions in the zipfile module. Patch by Serhiy Storchaka.
• Issue #16481: multiprocessing no longer leaks process handles on Windows.
• Issue #16140: The subprocess module no longer double closes its child subprocess.PIPE parent file descriptors on child error prior to exec().
• Remove a bare print to stdout from the subprocess module that could have happened if the child process wrote garbage to its pre-exec error pipe.
• Issue #16327: The subprocess module no longer leaks file descriptors used for stdin/stdout/stderr pipes to the child when fork() fails.
• Issue #14396: Handle the odd rare case of waitpid returning 0 when not expected in subprocess.Popen.wait().
• Issue #16411: Fix a bug where zlib.decompressobj().flush() might try to access previously-freed memory. Patch by Serhiy Storchaka.
• Issue #16357: fix calling accept() on a SSLSocket created through SSLContext.wrap_socket(). Original patch by Jeff McNeil.
• Issue #16409: The reporthook callback made by the legacy urllib.request.urlretrieve API now properly supplies a constant non-zero block_size as it did in Python 3.2 and 2.7. This matches the behavior of urllib.request.URLopener.retrieve.
• Issue #16431: Use the type information when constructing a Decimal subtype from a Decimal argument.
• Issue #16350: zlib.decompressobj().decompress() now accumulates data from successive calls after EOF in unused_data, instead of only saving the argument to the last call. decompressobj().flush() now correctly sets unused_data and unconsumed_tail. A bug in the handling of MemoryError when setting the unconsumed_tail attribute has also been fixed. Patch by Serhiy Storchaka.
• Issue #12759: sre_parse now raises a proper error when the name of the group is missing. Initial patch by Serhiy Storchaka.
• Issue #16152: fix tokenize to ignore whitespace at the end of the code when no newline is found. Patch by Ned Batchelder.
• Issue #16230: Fix a crash in select.select() when one the lists changes size while iterated on. Patch by Serhiy Storchaka.
• Issue #16228: Fix a crash in the json module where a list changes size while it is being encoded. Patch by Serhiy Storchaka.
• Issue #14897: Enhance error messages of struct.pack and struct.pack_into. Patch by Matti Mäki.
• Issue #12890: cgitb no longer prints spurious <p> tags in text mode when the logdir option is specified.
• Issue #16307: Fix multiprocessing.Pool.map_async not calling its callbacks. Patch by Janne Karila.
• Issue #16250: Fix URLError invocation with proper args.
• Issue #16116: Fix include and library paths to be correct when building C extensions in venvs.
• Issue #16245: Fix the value of a few entities in html.entities.html5.
• Issue #14398: Fix size truncation and overflow bugs in the bz2 module.
• Issue #16220: wsgiref now always calls close() on an iterable response. Patch by Brent Tubbs.
• Issue #16270: urllib may hang when used for retrieving files via FTP by using a context manager. Patch by Giampaolo Rodola’.
• Issue #16461: Wave library should be able to deal with 4GB wav files, and sample rate of 44100 Hz.
• Issue #16176: Properly identify Windows 8 via platform.platform()
• Issue #16114: The subprocess module no longer provides a misleading error message stating that args[0] did not exist when either the cwd or executable keyword arguments specified a path that did not exist.
• Issue #16169: Fix ctypes.WinError()’s confusion between errno and winerror.
• Issue #16076: Made _elementtree.Element pickleable in a way that is compatible with the Python Element. Pickling/unpickling of xml.etree.ElementTree.Element works again - this was a temporary regression from 3.2 where the by-default imported _elementtree had no pickling capability.
• Issue #16089: Allow ElementTree.TreeBuilder to work again with a non-Element element_factory (fixes a regression in SimpleTAL).
• Issue #16913: Fix Element.itertext()’s handling of text with XML entities.,
• Issue #16034: Fix performance regressions in the new bz2.BZ2File implementation. Initial patch by Serhiy Storchaka.
• Issue #16112: platform.architecture does not correctly escape argument to /usr/bin/file. Patch by David Benjamin.
• Issue #15756: subprocess.poll() now properly handles errno.ECHILD to return a returncode of 0 when the child has already exited or cannot be waited on.
• Issue #15323: Improve failure message of Mock.assert_called_once_with().
• Issue #16064: unittest -m claims executable is “python”, not “python3”.
• Issue #12376: Pass on parameters in TextTestResult.__init__() super call.
• Issue #15222: Insert blank line after each message in mbox mailboxes.
• Issue #16013: Fix csv.Reader parsing issue with ending quote characters. Patch by Serhiy Storchaka.
• Issue #15421: Fix an OverflowError in Calendar.itermonthdates() after datetime.MAXYEAR. Patch by Cédric Krier.
• Issue #15970: xml.etree.ElementTree now serializes correctly the empty HTML elements ‘meta’ and ‘param’.
• Issue #15842: The SocketIO.{readable,writable,seekable} methods now raise ValueError when the file-like object is closed. Patch by Alessandro Moura.
• Issue #15876: Fix a refleak in the curses module: window.encoding.
• Issue #15881: Fix atexit hook in multiprocessing. Original patch by Chris McDonough.
• Issue #15841: The readable(), writable() and seekable() methods of io.BytesIO and io.StringIO objects now raise ValueError when the object has been closed. Patch by Alessandro Moura.
• Issue #15447: Use subprocess.DEVNULL in webbrowser, instead of opening os.devnull explicitly and leaving it open.
• Issue #15509: webbrowser.UnixBrowser no longer passes empty arguments to Popen when %action substitutions produce empty strings.
• Issue #12776, issue #11839: Call argparse type function (specified by add_argument) only once. Before, the type function was called twice in the case where the default was specified and the argument was given as well. This was especially problematic for the FileType type, as a default file would always be opened, even if a file argument was specified on the command line.
• Issue #15906: Fix a regression in argparse caused by the preceding change, when action='append', type='str' and default=[].

IDLE

• Issue #17114: IDLE now uses non-strict config parser.
• Issue #9290: In IDLE the sys.std* streams now implement io.TextIOBase interface and support all mandatory methods and properties.
• Issue #16829: IDLE printing no longer fails if there are spaces or other special characters in the file path.
• Issue #16491: IDLE now prints chained exception tracebacks.
• Issue #16819: IDLE method completion now correctly works for bytes literals.
• Issue #16504: IDLE now catches SyntaxErrors raised by tokenizer. Patch by Roger Serwy.
• Issue #16511: Use default IDLE width and height if config param is not valid. Patch Serhiy Storchaka.
• Issue #1207589: Add Cut/Copy/Paste items to IDLE right click Context Menu Patch by Todd Rovito.

Tests

• Issue #17448: test_sax now skips if there are no xml parsers available instead of raising an ImportError.
• Issue #11420: make test suite pass with -B/DONTWRITEBYTECODE set. Initial patch by Thomas Wouters.
• Issue #10652: make tcl/tk tests run after __all__ test, patch by Zachary Ware.
• Issue #11963: remove human verification from test_parser and test_subprocess.
• Issue #11732: add a new suppress_crash_popup() context manager to test.support that disables crash popups on Windows and use it in test_faulthandler and test_capi.
• Issue #13898: test_ssl no longer prints a spurious stack trace on Ubuntu.
• Issue #17249: convert a test in test_capi to use unittest and reap threads.
• Issue #17041: Fix testing when Python is configured with the –without-doc-strings.
• Issue #16923: Fix ResourceWarnings in test_ssl.
• Issue #15539: Added regression tests for Tools/scripts/pindent.py.
• Issue #17479: test_io now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17066: test_robotparser now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17334: test_index now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17333: test_imaplib now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17082: test_dbm* now work with unittest test discovery. Patch by Zachary Ware.
• Issue #17079: test_ctypes now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17304: test_hash now works with unittest test discovery. Patch by Zachary Ware.
• Issue #17303: test_future* now work with unittest test discovery. Patch by Zachary Ware.
• Issue #17163: test_file now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16925: test_configparser now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16918: test_codecs now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16919: test_crypt now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16910: test_bytes, test_unicode, and test_userstring now work with unittest test discovery. Patch by Zachary Ware.
• Issue #16905: test_warnings now works with unittest test discovery. Initial patch by Berker Peksag.
• Issue #16898: test_bufio now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16888: test_array now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16896: test_asyncore now works with unittest test discovery. Patch by Zachary Ware.
• Issue #16897: test_bisect now works with unittest test discovery. Initial patch by Zachary Ware.
• Issue #16852: test_genericpath, test_posixpath, test_ntpath, and test_macpath now work with unittest test discovery. Patch by Zachary Ware.
• Issue #16748: test_heapq now works with unittest test discovery.
• Issue #15324: Fix regrtest parsing of –fromfile, –match, and –randomize options.
• Issue #16702: test_urllib2_localnet tests now correctly ignores proxies for localhost tests.
• Issue #16664: Add regression tests for glob’s behaviour concerning entries starting with a ”.”. Patch by Sebastian Kreft.
• Issue #16559: Add more tests for the json module, including some from the official test suite at json.org. Patch by Serhiy Storchaka.
• Issue #16661: Fix the os.getgrouplist() test by not assuming that it gives the same output as id -G.
• Issue #16115: Add some tests for the executable argument to subprocess.Popen(). Initial patch by Kushal Das.
• Issue #16126: PyErr_Format format mismatch in _testcapimodule.c. Patch by Serhiy Storchaka.
• Issue #15304: Fix warning message when os.chdir() fails inside test.support.temp_cwd(). Patch by Chris Jerdonek.
• Issue #15802: Fix test logic in TestMaildir.test_create_tmp(). Patch by Serhiy Storchaka.
• Issue #15557: Add a test suite for the webbrowser module, thanks to Anton Barkovsky.
• Issue #16698: Skip posix test_getgroups when built with OS X deployment target prior to 10.6.

Build

• Issue #17550: Fix the –enable-profiling configure switch.
• Issue #17425: Build with openssl 1.0.1d on Windows.
• Issue #16754: Fix the incorrect shared library extension on linux. Introduce two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.
• Issue #5033: Fix building of the sqlite3 extension module when the SQLite library version has “beta” in it. Patch by Andreas Pelme.
• Issue #17228: Fix building without pymalloc.
• Issue #3718: Use AC_ARG_VAR to set MACHDEP in configure.ac.
• Issue #17031: Fix running regen in cross builds.
• Issue #3754: fix typo in pthread AC_CACHE_VAL.
• Issue #15484: Fix _PYTHON_PROJECT_BASE for srcdir != builddir builds; use _PYTHON_PROJECT_BASE in distutils/sysconfig.py.
• Issue #17029: Let h2py search the multiarch system include directory.
• Issue #16953: Fix socket module compilation on platforms with HAVE_BROKEN_POLL. Patch by Jeffrey Armstrong.
• Issue #16836: Enable IPv6 support even if IPv6 is disabled on the build host.
• Cross compiling needs host and build settings. configure no longer creates a broken PYTHON_FOR_BUILD variable when –build is missing.
• Fix cross compiling issue in setup.py, ensure that lib_dirs and inc_dirs are defined in cross compiling mode, too.
• Issue #16593: Have BSD ‘make -s’ do the right thing, thanks to Daniel Shahaf
• Issue #16262: fix out-of-src-tree builds, if mercurial is not installed.
• Issue #15298: ensure _sysconfigdata is generated in build directory, not source directory.
• Issue #15833: Fix a regression in 3.3 that resulted in exceptions being raised if importlib failed to write byte-compiled files. This affected attempts to build Python out-of-tree from a read-only source directory.
• Issue #15923: Fix a mistake in asdl_c.py that resulted in a TypeError after 2801bf875a24 (see #15801).
• Issue #15819: Make sure we can build Python out-of-tree from a read-only source directory. (Somewhat related to issue #9860.)
• Issue #15587: Enable Tk high-resolution text rendering on Macs with Retina displays. Applies to Tkinter apps, such as IDLE, on OS X framework builds linked with Cocoa Tk 8.5.
• Issue #17161: make install now also installs a python3 man page.

C-API

• Issue #16881: Fix Py_ARRAY_LENGTH macro for GCC < 3.1.

Documentation

• Issue 17538: Document XML vulnerabilties
• Issue #16642: sched.scheduler timefunc initial default is time.monotonic. Patch by Ramchandra Apte
• Issue #17047: remove doubled words in docs and docstrings reported by Serhiy Storchaka and Matthew Barnett.
• Issue #15465: Document the versioning macros in the C API docs rather than the standard library docs. Patch by Kushal Das.
• Issue #16406: Combine the pages for uploading and registering to PyPI.
• Issue #16403: Document how distutils uses the maintainer field in PKG-INFO. Patch by Jyrki Pulliainen.
• Issue #16695: Document how glob handles filenames starting with a dot. Initial patch by Jyrki Pulliainen.
• Issue #8890: Stop advertising an insecure practice by replacing uses of the /tmp directory with better alternatives in the documentation. Patch by Geoff Wilson.
• Issue #17203: add long option names to unittest discovery docs.
• Issue #13094: add “Why do lambdas defined in a loop with different values all return the same result?” programming FAQ.
• Issue #14901: Update portions of the Windows FAQ. Patch by Ashish Nitin Patil.
• Issue #16267: Better document the 3.3+ approach to combining @abstractmethod with @staticmethod, @classmethod and @property
• Issue #15209: Clarify exception chaining description in exceptions module documentation
• Issue #15990: Improve argument/parameter documentation.
• Issue #16209: Move the documentation for the str built-in function to a new str class entry in the “Text Sequence Type” section.
• Issue #13538: Improve str() and object.__str__() documentation.
• Issue #16489: Make it clearer that importlib.find_loader() requires any and all packages to be separately imported.
• Issue #16400: Update the description of which versions of a given package PyPI displays.
• Issue #15677: Document that zlib and gzip accept a compression level of 0 to mean ‘no compression’. Patch by Brian Brazil.
• Issue #16197: Update winreg docstrings and documentation to match code. Patch by Zachary Ware.
• Issue #8040: added a version switcher to the documentation. Patch by Yury Selivanov.
• Issue #16241: Document -X faulthandler command line option. Patch by Marek Šuppa.
• Additional comments and some style changes in the concurrent.futures URL retrieval example
• Issue #16115: Improve subprocess.Popen() documentation around args, shell, and executable arguments.
• Issue #15533: Clarify docs and add tests for subprocess.Popen()‘s cwd argument.
• Issue #15979: Improve timeit documentation.
• Issue #16036: Improve documentation of built-in int()‘s signature and arguments.
• Issue #15935: Clarification of argparse docs, re: add_argument() type and default arguments. Patch contributed by Chris Jerdonek.
• Issue #11964: Document a change in v3.2 to the behavior of the indent parameter of json encoding operations.
• Issue #15116: Remove references to appscript as it is no longer being supported.

Tools/Demos

• Issue #17156: pygettext.py now uses an encoding of source file and correctly writes and escapes non-ascii characters.
• Issue #15539: Fix a number of bugs in Tools/scripts/pindent.py. Now pindent.py works with a “with” statement. pindent.py no longer produces improper indentation. pindent.py now works with continued lines broken after “class” or “def” keywords and with continuations at the start of line.
• Issue #15378: Fix Tools/unicode/comparecodecs.py. Patch by Serhiy Storchaka.
• Issue #16476: Fix json.tool to avoid including trailing whitespace.
• Issue #16549: Make json.tool work again on Python 3 and add tests. Initial patch by Berker Peksag and Serhiy Storchaka.
• Issue #13301: use ast.literal_eval() instead of eval() in Tools/i18n/msgfmt.py Patch by Serhiy Storchaka.

Core and Builtins

• Issue #16046: Fix loading sourceless legacy .pyo files.
• Issue #16060: Fix refcounting bug when __trunc__() returns an object whose __int__() gives a non-integer. Patch by Serhiy Storchaka.

Extension Modules

• Issue #16012: Fix a regression in pyexpat. The parser’s UseForeignDTD() method doesn’t require an argument again.

Core and Builtins

• Issue #15900: Fix reference leak in PyUnicode_TranslateCharmap().
• Issue #15926: Fix crash after multiple reinitializations of the interpreter.
• Issue #15895: Fix FILE pointer leak in one error branch of PyRun_SimpleFileExFlags() when filename points to a pyc/pyo file, closeit is false an and set_main_loader() fails.
• Fixes for a few crash and memory leak regressions found by Coverity.

Library

• Issue #15882: Change _decimal to accept any coefficient tuple when constructing infinities. This is done for backwards compatibility with decimal.py: Infinity coefficients are undefined in _decimal (in accordance with the specification).
• Issue #15925: Fix a regression in email.util where the parsedate() and parsedate_tz() functions did not return None anymore when the argument could not be parsed.

Extension Modules

• Issue #15973: Fix a segmentation fault when comparing datetime timezone objects.
• Issue #15977: Fix memory leak in Modules/_ssl.c when the function _set_npn_protocols() is called multiple times, thanks to Daniel Sommermann.
• Issue #15969: faulthandler module: rename dump_tracebacks_later() to dump_traceback_later() and cancel_dump_tracebacks_later() to cancel_dump_traceback_later().
• _decimal module: use only C 89 style comments.

Core and Builtins

• Issue #13992: The trashcan mechanism is now thread-safe. This eliminates sporadic crashes in multi-thread programs when several long deallocator chains ran concurrently and involved subclasses of built-in container types.
• Issue #15784: Modify OSError.__str__() to better distinguish between errno error numbers and Windows error numbers.
• Issue #15781: Fix two small race conditions in import’s module locking.

Library

• Issue #15847: Fix a regression in argparse, which did not accept tuples as argument lists anymore.
• Issue #15828: Restore support for C extensions in imp.load_module().
• Issue #15340: Fix importing the random module when /dev/urandom cannot be opened. This was a regression caused by the hash randomization patch.
• Issue #10650: Deprecate the watchexp parameter of the Decimal.quantize() method.
• Issue #15785: Modify window.get_wch() API of the curses module: return a character for most keys, and an integer for special keys, instead of always returning an integer. So it is now possible to distinguish special keys like keypad keys.
• Issue #14223: Fix window.addch() of the curses module for special characters like curses.ACS_HLINE: the Python function addch(int) and addch(bytes) is now calling the C function waddch()/mvwaddch() (as it was done in Python 3.2), instead of wadd_wch()/mvwadd_wch(). The Python function addch(str) is still calling the C function wadd_wch()/mvwadd_wch() if the Python curses is linked to libncursesw.

Build

• Issue #15822: Really ensure 2to3 grammar pickles are properly installed (replaces fixes for Issue #15645).

Documentation

• Issue #15814: The memoryview enhancements in 3.3.0 accidentally permitted the hashing of multi-dimensional memorviews and memoryviews with multi-byte item formats. The intended restrictions have now been documented - they will be correctly enforced in 3.3.1.

Core and Builtins

• Issue #15573: memoryview comparisons are now performed by value with full support for any valid struct module format definition.
• Issue #15316: When an item in the fromlist for __import__() doesn’t exist, don’t raise an error, but if an exception is raised as part of an import do let that propagate.
• Issue #15778: Ensure that str(ImportError(msg)) returns a str even when msg isn’t a str.
• Issue #2051: Source file permission bits are once again correctly copied to the cached bytecode file. (The migration to importlib reintroduced this problem because these was no regression test. A test has been added as part of this patch)
• Issue #15761: Fix crash when PYTHONEXECUTABLE is set on Mac OS X.
• Issue #15726: Fix incorrect bounds checking in PyState_FindModule. Patch by Robin Schreiber.
• Issue #15604: Update uses of PyObject_IsTrue() to check for and handle errors correctly. Patch by Serhiy Storchaka.
• Issue #14846: importlib.FileFinder now handles the case where the directory being searched is removed after a previous import attempt.

Library

• Issue #13370: Ensure that ctypes works on Mac OS X when Python is compiled using the clang compiler.
• Issue #13072: The array module’s ‘u’ format code is now deprecated and will be removed in Python 4.0.
• Issue #15544: Fix Decimal.__float__ to work with payload-carrying NaNs.
• Issue #15776: Allow pyvenv to work in existing directory with –clean.
• Issue #15249: email’s BytesGenerator now correctly mangles From lines (when requested) even if the body contains undecodable bytes.
• Issue #15777: Fix a refleak in _posixsubprocess.
• Issue ##665194: Update email.utils.localtime to use datetime.astimezone and correctly handle historic changes in UTC offsets.
• Issue #15199: Fix JavaScript’s default MIME type to application/javascript. Patch by Bohuslav Kabrda.
• Issue #12643: code.InteractiveConsole now respects sys.excepthook when displaying exceptions. Patch by Aaron Iles.
• Issue #13579: string.Formatter now understands the ‘a’ conversion specifier.
• Issue #15595: Fix subprocess.Popen(universal_newlines=True) for certain locales (utf-16 and utf-32 family). Patch by Chris Jerdonek.
• Issue #15477: In cmath and math modules, add workaround for platforms whose system-supplied log1p function doesn’t respect signs of zeros.
• Issue #15715: importlib.__import__() will silence an ImportError when the use of fromlist leads to a failed import.
• Issue #14669: Fix pickling of connections and sockets on Mac OS X by sending/receiving an acknowledgment after file descriptor transfer. TestPicklingConnection has been reenabled for Mac OS X.
• Issue #11062: Fix adding a message from file to Babyl mailbox.
• Issue #15646: Prevent equivalent of a fork bomb when using multiprocessing on Windows without the if __name__ == '__main__' idiom.

IDLE

• Issue #15678: Fix IDLE menus when started from OS X command line (3.3.0b2 regression).

Documentation

• Touched up the Python 2 to 3 porting guide.
• Issue #14674: Add a discussion of the json module’s standard compliance. Patch by Chris Rebert.
• Create a ‘Concurrent Execution’ section in the docs, and split up the ‘Optional Operating System Services’ section to use a more user-centric classification scheme (splitting them across the new CE section, IPC and text processing). Operating system limitations can be reflected with the Sphinx :platform: tag, it doesn’t make sense as part of the Table of Contents.
• Issue #4966: Bring the sequence docs up to date for the Py3k transition and the many language enhancements since they were original written.
• The “path importer” misnomer has been replaced with Eric Snow’s more-awkward-but-at-least-not-wrong suggestion of “path based finder” in the import system reference docs.
• Issue #15640: Document importlib.abc.Finder as deprecated.
• Issue #15630: Add an example for “continue” stmt in the tutorial. Patch by Daniel Ellis.

Tests

• Issue #15747: ZFS always returns EOPNOTSUPP when attempting to set the UF_IMMUTABLE flag (via either chflags or lchflags); refactor affected tests in test_posix.py to account for this.
• Issue #15285: Refactor the approach for testing connect timeouts using two external hosts that have been configured specifically for this type of test.
• Issue #15743: Remove the deprecated method usage in urllib tests. Patch by Jeff Knupp.
• Issue #15615: Add some tests for the json module’s handling of invalid input data. Patch by Kushal Das.

Build

• Output lib files for PGO build into PGO directory.
• Pick up 32-bit launcher from PGO directory on 64-bit PGO build.
• Drop PC\python_nt.h as it’s not used. Add input dependency on custom build step.
• Issue #15511: Drop explicit dependency on pythonxy.lib from _decimal amd64 configuration.
• Add missing PGI/PGO configurations for pywlauncher.
• Issue #15645: Ensure 2to3 grammar pickles are properly installed.

Core and Builtins

• Issue #15568: Fix the return value of yield from when StopIteration is raised by a custom iterator.
• Issue #13119: sys.stdout and sys.stderr are now using “rn” newline on Windows, as Python 2.
• Issue #15534: Fix the fast-search function for non-ASCII Unicode strings.
• Issue #15508: Fix the docstring for __import__() to have the proper default value of 0 for ‘level’ and to not mention negative levels since they are not supported.
• Issue #15425: Eliminated traceback noise from more situations involving importlib.
• Issue #14578: Support modules registered in the Windows registry again.
• Issue #15466: Stop using TYPE_INT64 in marshal, to make importlib.h (and other byte code files) equal between 32-bit and 64-bit systems.
• Issue #1692335: Move initial exception args assignment to BaseException.__new__() to help pickling of naive subclasses.
• Issue #12834: Fix PyBuffer_ToContiguous() for non-contiguous arrays.
• Issue #15456: Fix code __sizeof__() after #12399 change. Patch by Serhiy Storchaka.
• Issue #15404: Refleak in PyMethodObject repr.
• Issue #15394: An issue in PyModule_Create() that caused references to be leaked on some error paths has been fixed. Patch by Julia Lawall.
• Issue #15368: An issue that caused bytecode generation to be non-deterministic has been fixed.
• Issue #15202: Consistently use the name “follow_symlinks” for new parameters in os and shutil functions.
• Issue #15314: __main__.__loader__ is now set correctly during interpreter startup.
• Issue #15111: When a module imported using ‘from import’ has an ImportError inside itself, don’t mask that fact behind a generic ImportError for the module itself.
• Issue #15293: Add GC support to the AST base node type.
• Issue #15291: Fix a memory leak where AST nodes where not properly deallocated.
• Issue #15110: Fix the tracebacks generated by “import xxx” to not show the importlib stack frames.
• Issue #16369: Global PyTypeObjects not initialized with PyType_Ready(...).
• Issue #15020: The program name used to search for Python’s path is now “python3” under Unix, not “python”.
• Issue #15897: zipimport.c doesn’t check return value of fseek(). Patch by Felipe Cruz.
• Issue #15033: Fix the exit status bug when modules invoked using -m switch, return the proper failure return value (1). Patch contributed by Jeff Knupp.
• Issue #15229: An OSError subclass whose __init__ doesn’t call back OSError.__init__ could produce incomplete instances, leading to crashes when calling str() on them.
• Issue #15307: Virtual environments now use symlinks with framework builds on Mac OS X, like other POSIX builds.

Library

• Issue #14590: configparser now correctly strips inline comments when delimiter occurs earlier without preceding space.
• Issue #15424: Add a __sizeof__() implementation for array objects. Patch by Ludwig Hähne.
• Issue #15576: Allow extension modules to act as a package’s __init__ module.
• Issue #15502: Have importlib.invalidate_caches() work on sys.meta_path instead of sys.path_importer_cache.
• Issue #15163: Pydoc shouldn’t list __loader__ as module data.
• Issue #15471: Do not use mutable objects as defaults for importlib.__import__().
• Issue #15559: To avoid a problematic failure mode when passed to the bytes constructor, objects in the ipaddress module no longer implement __index__() (they still implement __int__() as appropriate).
• Issue #15546: Fix handling of pathological input data in the peek() and read1() methods of the BZ2File, GzipFile and LZMAFile classes.
• Issue #12655: Instead of requiring a custom type, os.sched_getaffinity() and os.sched_setaffinity() now use regular sets of integers to represent the CPUs a process is restricted to.
• Issue #15538: Fix compilation of the socket.getnameinfo() / socket.getaddrinfo() emulation code. Patch by Philipp Hagemeister.
• Issue #15519: Properly expose WindowsRegistryFinder in importlib (and use the correct term for it). Original patch by Eric Snow.
• Issue #15502: Bring the importlib ABCs into line with the current state of the import protocols given PEP 420. Original patch by Eric Snow.
• Issue #15499: Launching a webbrowser in Unix used to sleep for a few seconds. Original patch by Anton Barkovsky.
• Issue #15463: The faulthandler module truncates strings to 500 characters, instead of 100, to be able to display long file paths.
• Issue #6056: Make multiprocessing use setblocking(True) on the sockets it uses. Original patch by J Derek Wilson.
• Issue #15364: Fix sysconfig.get_config_var(‘srcdir’) to be an absolute path.
• Issue #15413: os.times() had disappeared under Windows.
• Issue #15402: An issue in the struct module that caused sys.getsizeof() to return incorrect results for struct.Struct instances has been fixed. Initial patch by Serhiy Storchaka.
• Issue #15232: When mangle_from is True, email.Generator now correctly mangles lines that start with ‘From ‘ that occur in a MIME preamble or epilogue.
• Issue #15094: Incorrectly placed #endif in _tkinter.c. Patch by Serhiy Storchaka.
• Issue #13922: argparse no longer incorrectly strips ‘–’s that appear after the first one.
• Issue #12353: argparse now correctly handles null argument values.
• Issue #10017, issue #14998: Fix TypeError using pprint on dictionaries with user-defined types as keys or other unorderable keys.
• Issue #15397: inspect.getmodulename() is now based directly on importlib via a new importlib.machinery.all_suffixes() API.
• Issue #14635: telnetlib will use poll() rather than select() when possible to avoid failing due to the select() file descriptor limit.
• Issue #15180: Clarify posixpath.join() error message when mixing str & bytes.
• Issue #15343: pkgutil now includes an iter_importer_modules implementation for importlib.machinery.FileFinder (similar to the way it already handled zipimport.zipimporter).
• Issue #15314: runpy now sets __main__.__loader__ correctly.
• Issue #15357: The import emulation in pkgutil is now deprecated. pkgutil uses importlib internally rather than the emulation.
• Issue #15233: Python now guarantees that callables registered with the atexit module will be called in a deterministic order.
• Issue #15238: shutil.copystat() now copies Linux “extended attributes”.
• Issue #15230: runpy.run_path now correctly sets __package__ as described in the documentation.
• Issue #15315: Support VS 2010 in distutils cygwincompiler.
• Issue #15294: Fix a regression in pkgutil.extend_path()’s handling of nested namespace packages.
• Issue #15056: imp.cache_from_source() and imp.source_from_cache() raise NotImplementedError when sys.implementation.cache_tag is set to None.
• Issue #15256: Grammatical mistake in exception raised by imp.find_module().
• Issue #5931: wsgiref environ variable SERVER_SOFTWARE will specify an implementation specific term like CPython, Jython instead of generic “Python”.
• Issue #13248: Remove obsolete argument “max_buffer_size” of BufferedWriter and BufferedRWPair, from the io module.
• Issue #13248: Remove obsolete argument “version” of argparse.ArgumentParser.
• Issue #14814: Implement more consistent ordering and sorting behaviour for ipaddress objects.
• Issue #14814: ipaddress network objects correctly return NotImplemented when compared to arbitrary objects instead of raising TypeError.
• Issue #14990: Correctly fail with SyntaxError on invalid encoding declaration.
• Issue #14814: ipaddress now provides more informative error messages when constructing instances directly (changes permitted during beta due to provisional API status).
• Issue #15247: io.FileIO now raises an error when given a file descriptor pointing to a directory.
• Issue #15261: Stop os.stat(fd) crashing on Windows when fd not open.
• Issue #15166: Implement imp.get_tag() using sys.implementation.cache_tag.
• Issue #15210: Catch KeyError when importlib.__init__() can’t find _frozen_importlib in sys.modules, not ImportError.
• Issue #15030: importlib.abc.PyPycLoader now supports the new source size header field in .pyc files.
• Issue #5346: Preserve permissions of mbox, MMDF and Babyl mailbox files on flush().
• Issue #10571: Fix the “–sign” option of distutils’ upload command. Patch by Jakub Wilk.
• Issue #9559: If messages were only added, a new file is no longer created and renamed over the old file when flush() is called on an mbox, MMDF or Babyl mailbox.
• Issue #10924: Fixed crypt.mksalt() to use a RNG that is suitable for cryptographic purpose.
• Issue #15184: Ensure consistent results of OS X configuration tailoring for universal builds by factoring out common OS X-specific customizations from sysconfig, distutils.sysconfig, distutils.util, and distutils.unixccompiler into a new module _osx_support.

C API

• Issue #15610: PyImport_ImportModuleEx() now uses a ‘level’ of 0 instead of -1.
• Issue #15169, issue #14599: Strip out the C implementation of imp.source_from_cache() used by PyImport_ExecCodeModuleWithPathnames() and used the Python code instead. Leads to PyImport_ExecCodeModuleObject() to not try to infer the source path from the bytecode path as PyImport_ExecCodeModuleWithPathnames() does.

Extension Modules

• Issue #6493: An issue in ctypes on Windows that caused structure bitfields of type ctypes.c_uint32 and width 32 to incorrectly be set has been fixed.
• Issue #15194: Update libffi to the 3.0.11 release.

IDLE

• Issue #13052: Fix IDLE crashing when replace string in Search/Replace dialog ended with \. Patch by Roger Serwy.

Tools/Demos

• Issue #15458: python-config gets a new option –configdir to print the $LIBPL value.
• Move importlib.test.benchmark to Tools/importbench.
• Issue #12605: The gdb hooks for debugging CPython (within Tools/gdb) have been enhanced to show information on more C frames relevant to CPython within the “py-bt” and “py-bt-full” commands:
  • C frames that are waiting on the GIL
  • C frames that are garbage-collecting
  • C frames that are due to the invocation of a PyCFunction

Documentation

• Issue #15041: Update “see also” list in tkinter documentation.
• Issue #15444: Use proper spelling for non-ASCII contributor names. Patch by Serhiy Storchaka.
• Issue #15295: Reorganize and rewrite the documentation on the import system.
• Issue #15230: Clearly document some of the limitations of the runpy module and nudge readers towards importlib when appropriate.
• Issue #15053: Copy Python 3.3 import lock change notice to all relevant functions in imp instead of just at the top of the relevant section.
• Issue #15288: Link to the term “loader” in notes in pkgutil about how things won’t work as expected in Python 3.3 and mark the requisite functions as “changed” since they will no longer work with modules directly imported by import itself.
• Issue #13557: Clarify effect of giving two different namespaces to exec() or execfile().
• Issue #15250: Document that filecmp.dircmp() compares files shallowly. Patch contributed by Chris Jerdonek.

Tests

• Issue #15467: Move helpers for __sizeof__() tests into test_support. Patch by Serhiy Storchaka.
• Issue #15320: Make iterating the list of tests thread-safe when running tests in multiprocess mode. Patch by Chris Jerdonek.
• Issue #15168: Move importlib.test to test.test_importlib.
• Issue #15091: Reactivate a test on UNIX which was failing thanks to a forgotten importlib.invalidate_caches() call.
• Issue #15230: Adopted a more systematic approach in the runpy tests.
• Issue #15300: Ensure the temporary test working directories are in the same parent folder when running tests in multiprocess mode from a Python build. Patch by Chris Jerdonek.
• Issue #15284: Skip {send,recv}msg tests in test_socket when IPv6 is not enabled. Patch by Brian Brazil.
• Issue #15277: Fix a resource leak in support.py when IPv6 is disabled. Patch by Brian Brazil.

Build

• Issue #11715: Fix multiarch detection without having Debian development tools (dpkg-dev) installed.
• Issue #15037: Build OS X installers with local copy of ncurses 5.9 libraries to avoid curses.unget_wch bug present in older versions of ncurses such as those shipped with OS X.
• Issue #15560: Fix building _sqlite3 extension on OS X with an SDK. Also, for OS X installers, ensure consistent sqlite3 behavior and feature availability by building a local copy of libsqlite3 rather than depending on the wide range of versions supplied with various OS X releases.
• Issue #8847: Disable COMDAT folding in Windows PGO builds.
• Issue #14018: Fix OS X Tcl/Tk framework checking when using OS X SDKs.
• Issue #16256: OS X installer now sets correct permissions for doc directory.
• Issue #15431: Add _freeze_importlib project to regenerate importlib.h on Windows. Patch by Kristján Valur Jónsson.
• Issue #14197: For OS X framework builds, ensure links to the shared library are created with the proper ABI suffix.
• Issue #14330: For cross builds, don’t use host python, use host search paths for host compiler.
• Issue #15235: Allow Berkley DB versions up to 5.3 to build the dbm module.
• Issue #15268: Search curses.h in /usr/include/ncursesw.

Core and Builtins

• Fix a (most likely) very rare memory leak when calling main() and not being able to decode a command-line argument.
• Issue #14815: Use Py_ssize_t instead of long for the object hash, to preserve all 64 bits of hash on Win64.
• Issue #12268: File readline, readlines and read() or readall() methods no longer lose data when an underlying read system call is interrupted. IOError is no longer raised due to a read system call returning EINTR from within these methods.
• Issue #11626: Add _SizeT functions to stable ABI.
• Issue #15142: Fix reference leak when deallocating instances of types created using PyType_FromSpec().
• Issue #10053: Don’t close FDs when FileIO.__init__ fails. Loosely based on the work by Hirokazu Yamamoto.
• Issue #15096: Removed support for ur’’ as the raw notation isn’t compatible with Python 2.x’s raw unicode strings.
• Issue #13783: Generator objects now use the identifier APIs internally
• Issue #14874: Restore charmap decoding speed to pre-PEP 393 levels. Patch by Serhiy Storchaka.
• Issue #15026: utf-16 encoding is now significantly faster (up to 10x). Patch by Serhiy Storchaka.
• Issue #11022: open() and io.TextIOWrapper are now calling locale.getpreferredencoding(False) instead of locale.getpreferredencoding() in text mode if the encoding is not specified. Don’t change temporary the locale encoding using locale.setlocale(), use the current locale encoding instead of the user preferred encoding.
• Issue #14673: Add Eric Snow’s sys.implementation implementation.
• Issue #15038: Optimize python Locks on Windows.

Library

• Issue #16305: Fix a segmentation fault occurring when interrupting math.factorial.
• Issue #12288: Consider ‘0’ and ‘0.0’ as valid initialvalue for tkinter SimpleDialog.
• Issue #15512: Add a __sizeof__ implementation for parser. Patch by Serhiy Storchaka.
• Issue #15469: Add a __sizeof__ implementation for deque objects. Patch by Serhiy Storchaka.
• Issue #15489: Add a __sizeof__ implementation for BytesIO objects. Patch by Serhiy Storchaka.
• Issue #15487: Add a __sizeof__ implementation for buffered I/O objects. Patch by Serhiy Storchaka.
• Issue #15514: Correct __sizeof__ support for cpu_set. Patch by Serhiy Storchaka.
• Issue #15177: Added dir_fd parameter to os.fwalk().
• Issue #15061: Re-implemented hmac.compare_digest() in C to prevent further timing analysis and to support all buffer protocol aware objects as well as ASCII only str instances safely.
• Issue #15164: Change return value of platform.uname() from a plain tuple to a collections.namedtuple.
• Support Mageia Linux in the platform module.
• Issue #11678: Support Arch linux in the platform module.
• Issue #15118: Change return value of os.uname() and os.times() from plain tuples to immutable iterable objects with named attributes (structseq objects).
• Speed up _decimal by another 10-15% by caching the thread local context that was last accessed. In the pi benchmark (64-bit platform, prec=9), _decimal is now only 1.5x slower than float.
• Remove the packaging module, which is not ready for prime time.
• Issue #15154: Add “dir_fd” parameter to os.rmdir, remove “rmdir” parameter from os.remove / os.unlink.
• Issue #4489: Add a shutil.rmtree that isn’t susceptible to symlink attacks. It is used automatically on platforms supporting the necessary os.openat() and os.unlinkat() functions. Main code by Martin von Löwis.
• Issue #15156: HTMLParser now uses the new “html.entities.html5” dictionary.
• Issue #11113: add a new “html5” dictionary containing the named character references defined by the HTML5 standard and the equivalent Unicode character(s) to the html.entities module.
• Issue #15114: the strict mode of HTMLParser and the HTMLParseError exception are deprecated now that the parser is able to parse invalid markup.
• Issue #3665: u and U escapes are now supported in unicode regular expressions. Patch by Serhiy Storchaka.
• Issue #15153: Added inspect.getgeneratorlocals to simplify white box testing of generator state updates
• Issue #13062: Added inspect.getclosurevars to simplify testing stateful closures
• Issue #11024: Fixes and additional tests for Time2Internaldate.
• Issue #14626: Large refactoring of functions / parameters in the os module. Many functions now support “dir_fd” and “follow_symlinks” parameters; some also support accepting an open file descriptor in place of a path string. Added os.support_* collections as LBYL helpers. Removed many functions only previously seen in 3.3 alpha releases (often starting with “f” or “l”, or ending with “at”). Originally suggested by Serhiy Storchaka; implemented by Larry Hastings.
• Issue #15008: Implement PEP 362 “Signature Objects”. Patch by Yury Selivanov.
• Issue: #15138: base64.urlsafe_{en,de}code() are now 3-4x faster.
• Issue #444582: Add shutil.which, for finding programs on the system path. Original patch by Erik Demaine, with later iterations by Jan Killian and Brian Curtin.
• Issue #14837: SSL errors now have library and reason attributes describing precisely what happened and in which OpenSSL submodule. The str() of a SSLError is also enhanced accordingly.
• Issue #9527: datetime.astimezone() method will now supply a class timezone instance corresponding to the system local timezone when called with no arguments.
• Issue #14653: email.utils.mktime_tz() no longer relies on system mktime() when timezone offest is supplied.
• Issue #14684: zlib.compressobj() and zlib.decompressobj() now support the use of predefined compression dictionaries. Original patch by Sam Rushing.
• Fix GzipFile’s handling of filenames given as bytes objects.
• Issue #14772: Return destination values from some shutil functions.
• Issue #15064: Implement context manager protocol for multiprocessing types
• Issue #15101: Make pool finalizer avoid joining current thread.
• Issue #14657: The frozen instance of importlib used for bootstrap is now also the module imported as importlib._bootstrap.
• Issue #14055: Add __sizeof__ support to _elementtree.
• Issue #15054: A bug in tokenize.tokenize that caused string literals with ‘b’ prefixes to be incorrectly tokenized has been fixed. Patch by Serhiy Storchaka.
• Issue #15006: Allow equality comparison between naive and aware time or datetime objects.
• Issue #15036: Mailbox no longer throws an error if a flush is done between operations when removing or changing multiple items in mbox, MMDF, or Babyl mailboxes.
• Issue #14059: Implement multiprocessing.Barrier.
• Issue #15061: The inappropriately named hmac.secure_compare has been renamed to hmac.compare_digest, restricted to operating on bytes inputs only and had its documentation updated to more accurately reflect both its intent and its limitations
• Issue #13841: Make child processes exit using sys.exit() on Windows.
• Issue #14936: curses_panel was converted to PEP 3121 and PEP 384 API. Patch by Robin Schreiber.
• Issue #1667546: On platforms supporting tm_zone and tm_gmtoff fields in struct tm, time.struct_time objects returned by time.gmtime(), time.localtime() and time.strptime() functions now have tm_zone and tm_gmtoff attributes. Original patch by Paul Boddie.
• Rename adjusted attribute to adjustable in time.get_clock_info() result.
• Issue #3518: Remove references to non-existent BaseManager.from_address() method.
• Issue #13857: Added textwrap.indent() function (initial patch by Ezra Berch)
• Issue #2736: Added datetime.timestamp() method.
• Issue #13854: Make multiprocessing properly handle non-integer non-string argument to SystemExit.
• Issue #12157: Make pool.map() empty iterables correctly. Initial patch by mouad.
• Issue #11823: disassembly now shows argument counts on calls with keyword args.
• Issue #14711: os.stat_float_times() has been deprecated.
• LZMAFile now accepts the modes “rb”/”wb”/”ab” as synonyms of “r”/”w”/”a”.
• The bz2 and lzma modules now each contain an open() function, allowing compressed files to readily be opened in text mode as well as binary mode.
• BZ2File.__init__() and LZMAFile.__init__() now accept a file object as their first argument, rather than requiring a separate “fileobj” argument.
• gzip.open() now accepts file objects as well as filenames.
• Issue #14992: os.makedirs(path, exist_ok=True) would raise an OSError when the path existed and had the S_ISGID mode bit set when it was not explicitly asked for. This is no longer an exception as mkdir cannot control if the OS sets that bit for it or not.
• Issue #14989: Make the CGI enable option to http.server available via command line.
• Issue #14987: Add a missing import statement to inspect.
• Issue #1079: email.header.decode_header now correctly parses all the examples in RFC2047. There is a necessary visible behavior change: the leading and/or trailing whitespace on ASCII parts is now preserved.
• Issue #14969: Better handling of exception chaining in contextlib.ExitStack
• Issue #14963: Convert contextlib.ExitStack.__exit__ to use an iterative algorithm (Patch by Alon Horev)
• Issue #14785: Add sys._debugmallocstats() to help debug low-level memory allocation issues
• Issue #14443: Ensure that .py files are byte-compiled with the correct Python executable within bdist_rpm even on older versions of RPM

C-API

• Issue #15146: Add PyType_FromSpecWithBases. Patch by Robin Schreiber.
• Issue #15042: Add PyState_AddModule and PyState_RemoveModule. Add version guard for Py_LIMITED_API additions. Patch by Robin Schreiber.
• Issue #13783: Inadvertent additions to the public C API in the PEP 380 implementation have either been removed or marked as private interfaces.

Extension Modules

• Issue #15000: Support the “unique” x32 architecture in _posixsubprocess.c.

IDLE

• Issue #9803: Don’t close IDLE on saving if breakpoint is open. Patch by Roger Serwy.
• Issue #14962: Update text coloring in IDLE shell window after changing options. Patch by Roger Serwy.

Documentation

• Issue #15176: Clarified behavior, documentation, and implementation of os.listdir().
• Issue #14982: Document that pkgutil’s iteration functions require the non-standard iter_modules() method to be defined by an importer (something the importlib importers do not define).
• Issue #15081: Document PyState_FindModule. Patch by Robin Schreiber.
• Issue #14814: Added first draft of ipaddress module API reference

Tests

• Issue #15187: Bugfix: remove temporary directories test_shutil was leaving behind.
• Issue #14769: test_capi now has SkipitemTest, which cleverly checks for “parity” between PyArg_ParseTuple() and the Python/getargs.c static function skipitem() for all possible “format units”.
• test_nntplib now tolerates being run from behind NNTP gateways that add “X-Antivirus” headers to articles
• Issue #15043: test_gdb is now skipped entirely if gdb security settings block loading of the gdb hooks
• Issue #14963: Add test cases for exception handling behaviour in contextlib.ExitStack (Initial patch by Alon Horev)

Build

• Issue #13590: Improve support for OS X Xcode 4:

  • Try to avoid building Python or extension modules with problematic llvm-gcc compiler.
  • Since Xcode 4 removes ppc support, extension module builds now check for ppc compiler support and automatically remove ppc and ppc64 archs when not available.
  • Since Xcode 4 no longer install SDKs in default locations, extension module builds now revert to using installed headers and libs if the SDK used to build the interpreter is not available.
  • Update ./configure to use better defaults for universal builds; in particular, –enable-universalsdk=yes uses the Xcode default SDK and –with-universal-archs now defaults to “intel” if ppc not available.

• Issue #14225: Fix Unicode support for curses (#12567) on OS X

• Issue #14928: Fix importlib bootstrap issues by using a custom executable (Modules/_freeze_importlib) to build Python/importlib.h.

Core and Builtins

• Issue #14835: Make plistlib output empty arrays & dicts like OS X. Patch by Sidney San Martín.
• Issue #14744: Use the new _PyUnicodeWriter internal API to speed up str%args and str.format(args).
• Issue #14930: Make memoryview objects weakrefable.
• Issue #14775: Fix a potential quadratic dict build-up due to the garbage collector repeatedly trying to untrack dicts.
• Issue #14857: fix regression in references to PEP 3135 implicit __class__ closure variable (Reopens issue #12370)
• Issue #14712 (PEP 405): Virtual environments. Implemented by Vinay Sajip.
• Issue #14660 (PEP 420): Namespace packages. Implemented by Eric Smith.
• Issue #14494: Fix __future__.py and its documentation to note that absolute imports are the default behavior in 3.0 instead of 2.7. Patch by Sven Marnach.
• Issue #9260: A finer-grained import lock. Most of the import sequence now uses per-module locks rather than the global import lock, eliminating well-known issues with threads and imports.
• Issue #14624: UTF-16 decoding is now 3x to 4x faster on various inputs. Patch by Serhiy Storchaka.
• asdl_seq and asdl_int_seq are now Py_ssize_t sized.
• Issue #14133 (PEP 415): Implement suppression of __context__ display with an attribute on BaseException. This replaces the original mechanism of PEP 409.
• Issue #14417: Mutating a dict during lookup now restarts the lookup instead of raising a RuntimeError (undoes issue #14205).
• Issue #14738: Speed-up UTF-8 decoding on non-ASCII data. Patch by Serhiy Storchaka.
• Issue #14700: Fix two broken and undefined-behaviour-inducing overflow checks in old-style string formatting.

Library

• Issue #14690: Use monotonic clock instead of system clock in the sched, subprocess and trace modules.
• Issue #14443: Tell rpmbuild to use the correct version of Python in bdist_rpm. Initial patch by Ross Lagerwall.
• Issue #12515: email now registers a defect if it gets to EOF while parsing a MIME part without seeing the closing MIME boundary.
• Issue #1672568: email now always decodes base64 payloads, adding padding and ignoring non-base64-alphabet characters if needed, and registering defects for any such problems.
• Issue #14925: email now registers a defect when the parser decides that there is a missing header/body separator line. MalformedHeaderDefect, which the existing code would never actually generate, is deprecated.
• Issue #10365: File open dialog now works instead of crashing even when the parent window is closed before the dialog. Patch by Roger Serwy.
• Issue #8739: Updated smtpd to support RFC 5321, and added support for the RFC 1870 SIZE extension.
• Issue #665194: Added a localtime function to email.utils to provide an aware local datetime for use in setting Date headers.
• Issue #12586: Added new provisional policies that implement convenient unicode support for email headers. See What’s New for details.
• Issue #14731: Refactored email Policy framework to support full backward compatibility with Python 3.2 by default yet allow for the introduction of new features through new policies. Note that Policy.must_be_7bit is renamed to cte_type.
• Issue #14876: Use user-selected font for highlight configuration.
• Issue #14920: Fix the help(urllib.parse) failure on locale C on terminals. Have ascii characters in help.
• Issue #14548: Make multiprocessing finalizers check pid before running to cope with possibility of gc running just after fork.
• Issue #14036: Add an additional check to validate that port in urlparse does not go in illegal range and returns None.
• Issue #14862: Add missing names to os.__all__
• Issue #14875: Use float(‘inf’) instead of float(‘1e66666’) in the json module.
• Issue #13585: Added contextlib.ExitStack
• PEP 3144, Issue #14814: Added the ipaddress module
• Issue #14426: Correct the Date format in Expires attribute of Set-Cookie Header in Cookie.py.
• Issue #14588: The types module now provide new_class() and prepare_class() functions to support PEP 3115 compliant dynamic class creation. Patch by Daniel Urban and Nick Coghlan.
• Issue #13152: Allow to specify a custom tabsize for expanding tabs in textwrap. Patch by John Feuerstein.
• Issue #14721: Send the correct ‘Content-length: 0’ header when the body is an empty string ‘’. Initial Patch contributed by Arve Knudsen.
• Issue #14072: Fix parsing of ‘tel’ URIs in urlparse by making the check for ports stricter.
• Issue #9374: Generic parsing of query and fragment portions of url for any scheme. Supported both by RFC3986 and RFC2396.
• Issue #14798: Fix the functions in pyclbr to raise an ImportError when the first part of a dotted name is not a package. Patch by Xavier de Gaye.
• Issue #12098: multiprocessing on Windows now starts child processes using the same sys.flags as the current process. Initial patch by Sergey Mezentsev.
• Issue #13031: Small speed-up for tarfile when unzipping tarfiles. Patch by Justin Peel.
• Issue #14780: urllib.request.urlopen() now has a cadefault argument to use the default certificate store. Initial patch by James Oakley.
• Issue #14829: Fix bisect and range() indexing with large indices (>= 2 ** 32) under 64-bit Windows.
• Issue #14732: The _csv module now uses PEP 3121 module initialization. Patch by Robin Schreiber.
• Issue #14809: Add HTTP status codes introduced by RFC 6585 to http.server and http.client. Patch by EungJun Yi.
• Issue #14777: tkinter may return undecoded UTF-8 bytes as a string when accessing the Tk clipboard. Modify clipboad_get() to first request type UTF8_STRING when no specific type is requested in an X11 windowing environment, falling back to the current default type STRING if that fails. Original patch by Thomas Kluyver.
• Issue #14773: Fix os.fwalk() failing on dangling symlinks.
• Issue #12541: Be lenient with quotes around Realm field of HTTP Basic Authentation in urllib2.
• Issue #14807: move undocumented tarfile.filemode() to stat.filemode() and add doc entry. Add tarfile.filemode alias with deprecation warning.
• Issue #13815: TarFile.extractfile() now returns io.BufferedReader objects.
• Issue #14532: Add a secure_compare() helper to the hmac module, to mitigate timing attacks. Patch by Jon Oberheide.
• Add importlib.util.resolve_name().
• Issue #14366: Support lzma compression in zip files. Patch by Serhiy Storchaka.
• Issue #13959: Introduce importlib.find_loader() and document imp.find_module/load_module as deprecated.
• Issue #14082: shutil.copy2() now copies extended attributes, if possible. Patch by Hynek Schlawack.
• Issue #13959: Make importlib.abc.FileLoader.load_module()/get_filename() and importlib.machinery.ExtensionFileLoader.load_module() have their single argument be optional. Allows for the replacement (and thus deprecation) of imp.load_source()/load_package()/load_compiled().
• Issue #13959: imp.get_suffixes() has been deprecated in favour of the new attributes on importlib.machinery: SOURCE_SUFFIXES, DEBUG_BYTECODE_SUFFIXES, OPTIMIZED_BYTECODE_SUFFIXES, BYTECODE_SUFFIXES, and EXTENSION_SUFFIXES. This led to an indirect deprecation of inspect.getmoduleinfo().
• Issue #14662: Prevent shutil failures on OS X when destination does not support chflag operations. Patch by Hynek Schlawack.
• Issue #14157: Fix time.strptime failing without a year on February 29th. Patch by Hynek Schlawack.
• Issue #14753: Make multiprocessing’s handling of negative timeouts the same as it was in Python 3.2.
• Issue #14583: Fix importlib bug when a package’s __init__.py would first import one of its modules then raise an error.
• Issue #14741: Fix missing support for Ellipsis (‘...’) in parser module.
• Issue #14697: Fix missing support for set displays and set comprehensions in parser module.
• Issue #14701: Fix missing support for ‘raise ... from’ in parser module.
• Add support for timeouts to the acquire() methods of multiprocessing’s lock/semaphore/condition proxies.
• Issue #13989: Add support for text mode to gzip.open().
• Issue #14127: The os.stat() result object now provides three additional fields: st_ctime_ns, st_mtime_ns, and st_atime_ns, providing those times as an integer with nanosecond resolution. The functions os.utime(), os.lutimes(), and os.futimes() now accept a new parameter, ns, which accepts mtime and atime as integers with nanosecond resolution.
• Issue #14127 and #10148: shutil.copystat now preserves exact mtime and atime on filesystems providing nanosecond resolution.

IDLE

• Issue #14958: Change IDLE systax highlighting to recognize all string and byte literals supported in Python 3.3.
• Issue #10997: Prevent a duplicate entry in IDLE’s “Recent Files” menu.
• Issue #14929: Stop IDLE 3.x from closing on Unicode decode errors when grepping. Patch by Roger Serwy.
• Issue #12510: Attempting to get invalid tooltip no longer closes IDLE. Other tooltipss have been corrected or improved and the number of tests has been tripled. Original patch by Roger Serwy.

Tools/Demos

• Issue #14695: Bring Tools/parser/unparse.py support up to date with the Python 3.3 Grammar.

Build

• Issue #14472: Update .gitignore. Patch by Matej Cepl.
• Upgrade Windows library versions: bzip 1.0.6, OpenSSL 1.0.1c.
• Issue #14693: Under non-Windows platforms, hashlib’s fallback modules are always compiled, even if OpenSSL is present at build time.
• Issue #13210: Windows build now uses VS2010, ported from VS2008.

C-API

• Issue #14705: The PyArg_Parse() family of functions now support the ‘p’ format unit, which accepts a “boolean predicate” argument. It converts any Python value into an integer–0 if it is “false”, and 1 otherwise.

Documentation

• Issue #14863: Update the documentation of os.fdopen() to reflect the fact that it’s only a thin wrapper around open() anymore.
• Issue #14588: The language reference now accurately documents the Python 3 class definition process. Patch by Nick Coghlan.
• Issue #14943: Correct a default argument value for winreg.OpenKey and correctly list the argument names in the function’s explanation.

Core and Builtins

• Issue #14699: Fix calling the classmethod descriptor directly.
• Issue #14433: Prevent msvcrt crash in interactive prompt when stdin is closed.
• Issue #14521: Make result of float(‘nan’) and float(‘-nan’) more consistent across platforms.
• Issue #14646: __import__() sets __loader__ if the loader did not.
• Issue #14605: No longer have implicit entries in sys.meta_path. If sys.meta_path is found to be empty, raise ImportWarning.
• Issue #14605: No longer have implicit entries in sys.path_hooks. If sys.path_hooks is found to be empty, a warning will be raised. None is now inserted into sys.path_importer_cache if no finder was discovered. This also means imp.NullImporter is no longer implicitly used.
• Issue #13903: Implement PEP 412. Individual dictionary instances can now share their keys with other dictionaries. Classes take advantage of this to share their instance dictionary keys for improved memory and performance.
• Issue #11603 (again): Setting __repr__ to __str__ now raises a RuntimeError when repr() or str() is called on such an object.
• Issue #14658: Fix binding a special method to a builtin implementation of a special method with a different name.
• Issue #14630: Fix a memory access bug for instances of a subclass of int with value 0.
• Issue #14339: Speed improvements to bin, oct and hex functions. Patch by Serhiy Storchaka.
• Issue #14385: It is now possible to use a custom type for the __builtins__ namespace, instead of a dict. It can be used for sandboxing for example. Raise also a NameError instead of ImportError if __build_class__ name if not found in __builtins__.
• Issue #12599: Be more strict in accepting None compared to a false-like object for importlib.util.module_for_loader and importlib.machinery.PathFinder.
• Issue #14612: Fix jumping around with blocks by setting f_lineno.
• Issue #14592: Attempting a relative import w/o __package__ or __name__ set in globals raises a KeyError.
• Issue #14607: Fix keyword-only arguments which started with __.
• Issue #10854: The ImportError raised when an extension module on Windows fails to import now uses the new path and name attributes from Issue #1559549.
• Issue #13889: Check and (if necessary) set FPU control word before calling any of the dtoa.c string <-> float conversion functions, on MSVC builds of Python. This fixes issues when embedding Python in a Delphi app.
• __import__() now matches PEP 328 and documentation by defaulting ‘index’ to 0 instead of -1 and removing support for negative values.
• Issue #2377: Make importlib the implementation of __import__().
• Issue #1559549: ImportError now has ‘name’ and ‘path’ attributes that are set using keyword arguments to its constructor. They are currently not set by import as they are meant for use by importlib.
• Issue #14474: Save and restore exception state in thread.start_new_thread() while writing error message if the thread leaves a unhandled exception.
• Issue #13019: Fix potential reference leaks in bytearray.extend(). Patch by Suman Saha.

Library

• Issue #14768: os.path.expanduser(‘~/a’) doesn’t works correctly when HOME is ‘/’.
• Issue #14371: Support bzip2 in zipfile module. Patch by Serhiy Storchaka.
• Issue #13183: Fix pdb skipping frames after hitting a breakpoint and running step. Patch by Xavier de Gaye.
• Issue #14696: Fix parser module to understand ‘nonlocal’ declarations.
• Issue #10941: Fix imaplib.Internaldate2tuple to produce correct result near the DST transition. Patch by Joe Peterson.
• Issue #9154: Fix parser module to understand function annotations.
• Issue #6085: In http.server.py SimpleHTTPServer.address_string returns the client ip address instead client hostname. Patch by Charles-François Natali.
• Issue #14309: Deprecate time.clock(), use time.perf_counter() or time.process_time() instead.
• Issue #14428: Implement the PEP 418. Add time.get_clock_info(), time.perf_counter() and time.process_time() functions, and rename time.steady() to time.monotonic().
• Issue #14646: importlib.util.module_for_loader() now sets __loader__ and __package__ (when possible).
• Issue #14664: It is now possible to use @unittest.skip{If,Unless} on a test class that doesn’t inherit from TestCase (i.e. a mixin).
• Issue #4892: multiprocessing Connections can now be transferred over multiprocessing Connections. Patch by Richard Oudkerk (sbt).
• Issue #14160: TarFile.extractfile() failed to resolve symbolic links when the links were not located in an archive subdirectory.
• Issue #14638: pydoc now treats non-string __name__ values as if they were missing, instead of raising an error.
• Issue #13684: Fix httplib tunnel issue of infinite loops for certain sites which send EOF without trailing rn.
• Issue #14605: Add importlib.abc.FileLoader, importlib.machinery.(FileFinder, SourceFileLoader, SourcelessFileLoader, ExtensionFileLoader).
• Issue #13959: imp.cache_from_source()/source_from_cache() now follow os.path.join()/split() semantics for path manipulation instead of its prior, custom semantics of caring the right-most path separator forward in path joining.
• Issue #2193: Allow ”:” character in Cookie NAME values.
• Issue #14629: tokenizer.detect_encoding will specify the filename in the SyntaxError exception if found at readline.__self__.name.
• Issue #14629: Raise SyntaxError in tokenizer.detect_encoding if the first two lines have non-UTF-8 characters without an encoding declaration.
• Issue #14308: Fix an exception when a “dummy” thread is in the threading module’s active list after a fork().
• Issue #11750: The Windows API functions scattered in the _subprocess and _multiprocessing.win32 modules now live in a single module “_winapi”. Patch by sbt.
• Issue #14087: multiprocessing: add Condition.wait_for(). Patch by sbt.
• Issue #14538: HTMLParser can now parse correctly start tags that contain a bare ‘/’.
• Issue #14452: SysLogHandler no longer inserts a UTF-8 BOM into the message.
• Issue #14386: Expose the dict_proxy internal type as types.MappingProxyType.
• Issue #13959: Make imp.reload() always use a module’s __loader__ to perform the reload.
• Issue #13959: Add imp.py and rename the built-in module to _imp, allowing for re-implementing parts of the module in pure Python.
• Issue #13496: Fix potential overflow in bisect.bisect algorithm when applied to a collection of size > sys.maxsize / 2.
• Have importlib take advantage of ImportError’s new ‘name’ and ‘path’ attributes.
• Issue #14399: zipfile now recognizes that the archive has been modified even if only the comment is changed. In addition, the TypeError that results from trying to set a non-binary value as a comment is now raised at the time the comment is set rather than at the time the zipfile is written.
• trace.CoverageResults.is_ignored_filename() now ignores any name that starts with “<” and ends with “>” instead of special-casing “<string>” and “<doctest ”.
• Issue #12537: The mailbox module no longer depends on knowledge of internal implementation details of the email package Message object.
• Issue #7978: socketserver now restarts the select() call when EINTR is returned. This avoids crashing the server loop when a signal is received. Patch by Jerzy Kozera.
• Issue #14522: Avoid duplicating socket handles in multiprocessing.connection. Patch by sbt.
• Don’t Py_DECREF NULL variable in io.IncrementalNewlineDecoder.
• Issue #3033: Add displayof parameter to tkinter font. Patch by Guilherme Polo.
• Issue #14482: Raise a ValueError, not a NameError, when trying to create a multiprocessing Client or Listener with an AF_UNIX type address under Windows. Patch by Popa Claudiu.
• Issue #802310: Generate always unique tkinter font names if not directly passed.
• Issue #14151: Raise a ValueError, not a NameError, when trying to create a multiprocessing Client or Listener with an AF_PIPE type address under non-Windows platforms. Patch by Popa Claudiu.
• Issue #14493: Use gvfs-open or xdg-open in webbrowser.

Build

• “make touch” will now touch generated files that are checked into Mercurial, after a “hg update” which failed to bring the timestamps into the right order.

Tests

• Issue #14026: In test_cmd_line_script, check that sys.argv is populated correctly for the various invocation approaches (Patch by Jason Yeo)
• Issue #14032: Fix incorrect variable name in test_cmd_line_script debugging message (Patch by Jason Yeo)
• Issue #14589: Update certificate chain for sha256.tbs-internet.com, fixing a test failure in test_ssl.
• Issue #14355: Regrtest now supports the standard unittest test loading, and will use it if a test file contains no test_main method.

IDLE

• Issue #8515: Set __file__ when run file in IDLE. Initial patch by Bruce Frederiksen.
• Issue #14496: Fix wrong name in idlelib/tabbedpages.py. Patch by Popa Claudiu.

Tools / Demos

• Issue #3561: The Windows installer now has an option, off by default, for placing the Python installation into the system “Path” environment variable.
• Issue #13165: stringbench is now available in the Tools/stringbench folder. It used to live in its own SVN project.

C-API

• Issue #14098: New functions PyErr_GetExcInfo and PyErr_SetExcInfo. Patch by Stefan Behnel.

Core and Builtins

• Issue #1683368: object.__new__ and object.__init__ raise a TypeError if they are passed arguments and their complementary method is not overridden.
• Issue #14378: Fix compiling ast.ImportFrom nodes with a “__future__” string as the module name that was not interned.
• Issue #14331: Use significantly less stack space when importing modules by allocating path buffers on the heap instead of the stack.
• Issue #14334: Prevent in a segfault in type.__getattribute__ when it was not passed strings.
• Issue #1469629: Allow cycles through an object’s __dict__ slot to be collected. (For example if x.__dict__ is x).
• Issue #14205: dict lookup raises a RuntimeError if the dict is modified during a lookup.
• Issue #14220: When a generator is delegating to another iterator with the yield from syntax, it needs to have its gi_running flag set to True.
• Issue #14435: Remove dedicated block allocator from floatobject.c and rely on the PyObject_Malloc() api like all other objects.
• Issue #14471: Fix a possible buffer overrun in the winreg module.
• Issue #14288: Allow the serialization of builtin iterators

Library

• Issue #14300: Under Windows, sockets created using socket.dup() now allow overlapped I/O. Patch by sbt.
• Issue #13872: socket.detach() now marks the socket closed (as mirrored in the socket repr()). Patch by Matt Joiner.
• Issue #14406: Fix a race condition when using concurrent.futures.wait( return_when=ALL_COMPLETED). Patch by Matt Joiner.
• Issue #5136: deprecate old, unused functions from tkinter.
• Issue #14416: syslog now defines the LOG_ODELAY and LOG_AUTHPRIV constants if they are defined in <syslog.h>.
• Issue #14295: Add unittest.mock
• Issue #7652: Add –with-system-libmpdec option to configure for linking the _decimal module against an installed libmpdec.
• Issue #14380: MIMEText now defaults to utf-8 when passed non-ASCII unicode with no charset specified.
• Issue #10340: asyncore - properly handle EINVAL in dispatcher constructor on OSX; avoid to call handle_connect in case of a disconnected socket which was not meant to connect.
• Issue #14204: The ssl module now has support for the Next Protocol Negotiation extension, if available in the underlying OpenSSL library. Patch by Colin Marc.
• Issue #3035: Unused functions from tkinter are marked as pending deprecated.
• Issue #12757: Fix the skipping of doctests when python is run with -OO so that it works in unittest’s verbose mode as well as non-verbose mode.
• Issue #7652: Integrate the decimal floating point libmpdec library to speed up the decimal module. Performance gains of the new C implementation are between 10x and 100x, depending on the application.
• Issue #14269: SMTPD now conforms to the RFC and requires a HELO command before MAIL, RCPT, or DATA.
• Issue #13694: asynchronous connect in asyncore.dispatcher does not set addr attribute.
• Issue #14344: fixed the repr of email.policy objects.
• Issue #11686: Added missing entries to email package __all__ lists (mostly the new Bytes classes).
• Issue #14335: multiprocessing’s custom Pickler subclass now inherits from the C-accelerated implementation. Patch by sbt.
• Issue #10484: Fix the CGIHTTPServer’s PATH_INFO handling problem.
• Issue #11199: Fix the with urllib which hangs on particular ftp urls.
• Improve the memory utilization and speed of functools.lru_cache.
• Issue #14222: Use the new time.steady() function instead of time.time() for timeout in queue and threading modules to not be affected of system time update.
• Issue #13248: Remove lib2to3.pytree.Base.get_prefix/set_prefix.
• Issue #14234: CVE-2012-0876: Randomize hashes of xml attributes in the hash table internal to the pyexpat module’s copy of the expat library to avoid a denial of service due to hash collisions. Patch by David Malcolm with some modifications by the expat project.
• Issue #12818: format address no longer needlessly escapes ()s in names when the name ends up being quoted.
• Issue #14062: BytesGenerator now correctly folds Header objects, including using linesep when folding.
• Issue #13839: When invoked on the command-line, the pstats module now accepts several filenames of profile stat files and merges them all. Patch by Matt Joiner.
• Issue #14291: Email now defaults to utf-8 for non-ASCII unicode headers instead of raising an error. This fixes a regression relative to 2.7.
• Issue #989712: Support using Tk without a mainloop.
• Issue #3835: Refuse to use unthreaded Tcl in threaded Python.
• Issue #2843: Add new Tk API to Tkinter.
• Issue #14184: Increase the default stack size for secondary threads on Mac OS X to avoid interpreter crashes when using threads on 10.7.
• Issue #14180: datetime.date.fromtimestamp(), datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp() now raise an OSError instead of ValueError if localtime() or gmtime() failed.
• Issue #14180: time.ctime(), gmtime(), time.localtime(), datetime.date.fromtimestamp(), datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp() now raises an OverflowError, instead of a ValueError, if the timestamp does not fit in time_t.
• Issue #14180: datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp() now round microseconds towards zero instead of rounding to nearest with ties going away from zero.
• Issue #10543: Fix unittest test discovery with Jython bytecode files.
• Issue #1178863: Separate initialisation from setting when initializing Tkinter.Variables; harmonize exceptions to ValueError; only delete variables that have not been deleted; assert that variable names are strings.
• Issue #14104: Implement time.monotonic() on Mac OS X, patch written by Nicholas Riley.
• Issue #13394: the aifc module now uses warnings.warn() to signal warnings.
• Issue #14252: Fix subprocess.Popen.terminate() to not raise an error under Windows when the child process has already exited.
• Issue #14223: curses.addch() is no more limited to the range 0-255 when the Python curses is not linked to libncursesw. It was a regression introduced in Python 3.3a1.
• Issue #14168: Check for presence of Element._attrs in minidom before accessing it.
• Issue #12328: Fix multiprocessing’s use of overlapped I/O on Windows. Also, add a multiprocessing.connection.wait(rlist, timeout=None) function for polling multiple objects at once. Patch by sbt.
• Issue #14007: Accept incomplete TreeBuilder objects (missing start, end, data or close method) for the Python implementation as well. Drop the no-op TreeBuilder().xml() method from the C implementation.
• Issue #14210: pdb now has tab-completion not only for command names, but also for their arguments, wherever possible.
• Issue #14310: Sockets can now be with other processes on Windows using the api socket.socket.share() and socket.fromshare().
• Issue #10576: The gc module now has a ‘callbacks’ member that will get called when garbage collection takes place.

Build

• Issue #14557: Fix extensions build on HP-UX. Patch by Adi Roiban.
• Issue #14387: Do not include accu.h from Python.h.
• Issue #14359: Only use O_CLOEXEC in _posixmodule.c if it is defined. Based on patch from Hervé Coatanhay.
• Issue #14321: Do not run pgen during the build if files are up to date.

Documentation

• Issue #14034: added the argparse tutorial.
• Issue #14324: Fix configure tests for cross builds.
• Issue #14327: Call AC_CANONICAL_HOST in configure.ac and check in config.{guess,sub}. Don’t use uname calls for cross builds.

Extension Modules

• Issue #9041: An issue in ctypes.c_longdouble, ctypes.c_double, and ctypes.c_float that caused an incorrect exception to be returned in the case of overflow has been fixed.
• Issue #14212: The re module didn’t retain a reference to buffers it was scanning, resulting in segfaults.
• Issue #14259: The finditer() method of re objects did not take any keyword arguments, contrary to the documentation.
• Issue #10142: Support for SEEK_HOLE/SEEK_DATA (for example, under ZFS).

Tests

• Issue #14442: Add missing errno import in test_smtplib.
• Issue #8315: (partial fix) python -m unittest test.test_email now works.

Core and Builtins

• Issue #14172: Fix reference leak when marshalling a buffer-like object (other than a bytes object).

• Issue #13521: dict.setdefault() now does only one lookup for the given key, making it “atomic” for many purposes. Patch by Filip Gruszczyński.

• PEP 409, Issue #6210: “raise X from None” is now supported as a means of suppressing the display of the chained exception context. The chained context still remains available as the __context__ attribute.

• Issue #10181: New memoryview implementation fixes multiple ownership and lifetime issues of dynamically allocated Py_buffer members (#9990) as well as crashes (#8305, #7433). Many new features have been added (See whatsnew/3.3), and the documentation has been updated extensively. The ndarray test object from _testbuffer.c implements all aspects of PEP-3118, so further development towards the complete implementation of the PEP can proceed in a test-driven manner.

  Thanks to Nick Coghlan, Antoine Pitrou and Pauli Virtanen for review and many ideas.

• Issue #12834: Fix incorrect results of memoryview.tobytes() for non-contiguous arrays.

• Issue #5231: Introduce memoryview.cast() method that allows changing format and shape without making a copy of the underlying memory.

• Issue #14084: Fix a file descriptor leak when importing a module with a bad encoding.

• Upgrade Unicode data to Unicode 6.1.

• Issue #14040: Remove rarely used file name suffixes for C extensions (under POSIX mainly).

• Issue #14051: Allow arbitrary attributes to be set of classmethod and staticmethod.

• Issue #13703: oCERT-2011-003: Randomize hashes of str and bytes to protect against denial of service attacks due to hash collisions within the dict and set types. Patch by David Malcolm, based on work by Victor Stinner.

• Issue #13020: Fix a reference leak when allocating a structsequence object fails. Patch by Suman Saha.

• Issue #13908: Ready types returned from PyType_FromSpec.

• Issue #11235: Fix OverflowError when trying to import a source file whose modification time doesn’t fit in a 32-bit timestamp.

• Issue #12705: A SyntaxError exception is now raised when attempting to compile multiple statements as a single interactive statement.

• Fix the builtin module initialization code to store the init function for future reinitialization.

• Issue #8052: The posix subprocess module would take a long time closing all possible file descriptors in the child process rather than just open file descriptors. It now closes only the open fds if possible for the default close_fds=True behavior.

• Issue #13629: Renumber the tokens in token.h so that they match the indexes into _PyParser_TokenNames.

• Issue #13752: Add a casefold() method to str.

• Issue #13761: Add a “flush” keyword argument to the print() function, used to ensure flushing the output stream.

• Issue #13645: pyc files now contain the size of the corresponding source code, to avoid timestamp collisions (especially on filesystems with a low timestamp resolution) when checking for freshness of the bytecode.

• PEP 380, Issue #11682: Add “yield from <x>” to support easy delegation to subgenerators (initial patch by Greg Ewing, integration into 3.3 by Renaud Blanch, Ryan Kelly, Zbigniew Jędrzejewski-Szmek and Nick Coghlan)

• Issue #13748: Raw bytes literals can now be written with the rb prefix as well as br.

• Issue #12736: Use full unicode case mappings for upper, lower, and title case.

• Issue #12760: Add a create mode to open(). Patch by David Townshend.

• Issue #13738: Simplify implementation of bytes.lower() and bytes.upper().

• Issue #13577: Built-in methods and functions now have a __qualname__. Patch by sbt.

• Issue #6695: Full garbage collection runs now clear the freelist of set objects. Initial patch by Matthias Troffaes.

• Fix OSError.__init__ and OSError.__new__ so that each of them can be overriden and take additional arguments (followup to issue #12555).

• Fix the fix for issue #12149: it was incorrect, although it had the side effect of appearing to resolve the issue. Thanks to Mark Shannon for noticing.

• Issue #13505: Pickle bytes objects in a way that is compatible with Python 2 when using protocols <= 2.

• Issue #11147: Fix an unused argument in _Py_ANNOTATE_MEMORY_ORDER. (Fix given by Campbell Barton).

• Issue #13503: Use a more efficient reduction format for bytearrays with pickle protocol >= 3. The old reduction format is kept with older protocols in order to allow unpickling under Python 2. Patch by Irmen de Jong.

• Issue #7111: Python can now be run without a stdin, stdout or stderr stream. It was already the case with Python 2. However, the corresponding sys module entries are now set to None (instead of an unusable file object).

• Issue #11849: Ensure that free()d memory arenas are really released on POSIX systems supporting anonymous memory mappings. Patch by Charles-François Natali.

• PEP 3155 / issue #13448: Qualified name for classes and functions.

• Issue #13436: Fix a bogus error message when an AST object was passed an invalid integer value.

• Issue #13411: memoryview objects are now hashable when the underlying object is hashable.

• Issue #13338: Handle all enumerations in _Py_ANNOTATE_MEMORY_ORDER to allow compiling extension modules with -Wswitch-enum on gcc. Initial patch by Floris Bruynooghe.

• Issue #10227: Add an allocation cache for a single slice object. Patch by Stefan Behnel.

• Issue #13393: BufferedReader.read1() now asks the full requested size to the raw stream instead of limiting itself to the buffer size.

• Issue #13392: Writing a pyc file should now be atomic under Windows as well.

• Issue #13333: The UTF-7 decoder now accepts lone surrogates (the encoder already accepts them).

• Issue #13389: Full garbage collection passes now clear the freelists for list and dict objects. They already cleared other freelists in the interpreter.

• Issue #13327: Remove the need for an explicit None as the second argument to os.utime, os.lutimes, os.futimes, os.futimens, os.futimesat, in order to update to the current time. Also added keyword argument handling to os.utimensat in order to remove the need for explicit None.

• Issue #13350: Simplify some C code by replacing most usages of PyUnicode_Format by PyUnicode_FromFormat.

• Issue #13342: input() used to ignore sys.stdin’s and sys.stdout’s unicode error handler in interactive mode (when calling into PyOS_Readline()).

• Issue #9896: Add start, stop, and step attributes to range objects.

• Issue #13343: Fix a SystemError when a lambda expression uses a global variable in the default value of a keyword-only argument: lambda *, arg=GLOBAL_NAME: None

• Issue #12797: Added custom opener parameter to builtin open() and FileIO.open().

• Issue #10519: Avoid unnecessary recursive function calls in setobject.c.

• Issue #10363: Deallocate global locks in Py_Finalize().

• Issue #13018: Fix reference leaks in error paths in dictobject.c. Patch by Suman Saha.

• Issue #13201: Define ‘==’ and ‘!=’ to compare range objects based on the sequence of values they define (instead of comparing based on object identity).

• Issue #1294232: In a few cases involving metaclass inheritance, the interpreter would sometimes invoke the wrong metaclass when building a new class object. These cases now behave correctly. Patch by Daniel Urban.

• Issue #12753: Add support for Unicode name aliases and named sequences. Both unicodedata.lookup() and ‘N{...}’ now resolve aliases, and unicodedata.lookup() resolves named sequences too.

• Issue #12170: The count(), find(), rfind(), index() and rindex() methods of bytes and bytearray objects now accept an integer between 0 and 255 as their first argument. Patch by Petri Lehtinen.

• Issue #12604: VTRACE macro expanded to no-op in _sre.c to avoid compiler warnings. Patch by Josh Triplett and Petri Lehtinen.

• Issue #12281: Rewrite the MBCS codec to handle correctly replace and ignore error handlers on all Windows versions. The MBCS codec is now supporting all error handlers, instead of only replace to encode and ignore to decode.

• Issue #13188: When called without an explicit traceback argument, generator.throw() now gets the traceback from the passed exception’s __traceback__ attribute. Patch by Petri Lehtinen.

• Issue #13146: Writing a pyc file is now atomic under POSIX.

• Issue #7833: Extension modules built using distutils on Windows will no longer include a “manifest” to prevent them failing at import time in some embedded situations.

• PEP 3151 / issue #12555: reworking the OS and IO exception hierarchy.

• Add internal API for static strings (_Py_identifier et al.).

• Issue #13063: the Windows error ERROR_NO_DATA (numbered 232 and described as “The pipe is being closed”) is now mapped to POSIX errno EPIPE (previously EINVAL).

• Issue #12911: Fix memory consumption when calculating the repr() of huge tuples or lists.

• PEP 393: flexible string representation. Thanks to Torsten Becker for the initial implementation, and Victor Stinner for various bug fixes.

• Issue #14081: The ‘sep’ and ‘maxsplit’ parameter to str.split, bytes.split, and bytearray.split may now be passed as keyword arguments.

• Issue #13012: The ‘keepends’ parameter to str.splitlines may now be passed as a keyword argument: “my_string.splitlines(keepends=True)”. The same change also applies to bytes.splitlines and bytearray.splitlines.

• Issue #7732: Don’t open a directory as a file anymore while importing a module. Ignore the direcotry if its name matchs the module name (e.g. “__init__.py”) and raise a ImportError instead.

• Issue #13021: Missing decref on an error path. Thanks to Suman Saha for finding the bug and providing a patch.

• Issue #12973: Fix overflow checks that relied on undefined behaviour in list_repeat (listobject.c) and islice_next (itertoolsmodule.c). These bugs caused test failures with recent versions of Clang.

• Issue #12904: os.utime, os.futimes, os.lutimes, and os.futimesat now write atime and mtime with nanosecond precision on modern POSIX platforms.

• Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now mapped to POSIX errno ENOTDIR (previously EINVAL).

• Issue #9200: The str.is* methods now work with strings that contain non-BMP characters even in narrow Unicode builds.

• Issue #12791: Break reference cycles early when a generator exits with an exception.

• Issue #12773: Make __doc__ mutable on user-defined classes.

• Issue #12766: Raise a ValueError when creating a class with a class variable that conflicts with a name in __slots__.

• Issue #12266: Fix str.capitalize() to correctly uppercase/lowercase titlecased and cased non-letter characters.

• Issue #12732: In narrow unicode builds, allow Unicode identifiers which fall outside the BMP.

• Issue #12575: Validate user-generated AST before it is compiled.

• Make type(None), type(Ellipsis), and type(NotImplemented) callable. They return the respective singleton instances.

• Forbid summing bytes with sum().

• Verify the types of AST strings and identifiers provided by the user before compiling them.

• Issue #12647: The None object now has a __bool__() method that returns False. Formerly, bool(None) returned False only because of special case logic in PyObject_IsTrue().

• Issue #12579: str.format_map() now raises a ValueError if used on a format string that contains positional fields. Initial patch by Julian Berman.

• Issue #10271: Allow warnings.showwarning() be any callable.

• Issue #11627: Fix segfault when __new__ on a exception returns a non-exception class.

• Issue #12149: Update the method cache after a type’s dictionary gets cleared by the garbage collector. This fixes a segfault when an instance and its type get caught in a reference cycle, and the instance’s deallocator calls one of the methods on the type (e.g. when subclassing IOBase). Diagnosis and patch by Davide Rizzo.

• Issue #9611, #9015: FileIO.read() clamps the length to INT_MAX on Windows.

• Issue #9642: Uniformize the tests on the availability of the mbcs codec, add a new HAVE_MBCS define.

• Issue #9642: Fix filesystem encoding initialization: use the ANSI code page on Windows if the mbcs codec is not available, and fail with a fatal error if we cannot get the locale encoding (if nl_langinfo(CODESET) is not available) instead of using UTF-8.

• When a generator yields, do not retain the caller’s exception state on the generator.

• Issue #12475: Prevent generators from leaking their exception state into the caller’s frame as they return for the last time.

• Issue #12291: You can now load multiple marshalled objects from a stream, with other data interleaved between marshalled objects.

• Issue #12356: When required positional or keyword-only arguments are not given, produce a informative error message which includes the name(s) of the missing arguments.

• Issue #12370: Fix super with no arguments when __class__ is overriden in the class body.

• Issue #12084: os.stat on Windows now works properly with relative symbolic links when called from any directory.

• Loosen type restrictions on the __dir__ method. __dir__ can now return any sequence, which will be converted to a list and sorted by dir().

• Issue #12265: Make error messages produced by passing an invalid set of arguments to a function more informative.

• Issue #12225: Still allow Python to build if Python is not in its hg repo or mercurial is not installed.

• Issue #1195: my_fgets() now always clears errors before calling fgets(). Fix the following case: sys.stdin.read() stopped with CTRL+d (end of file), raw_input() interrupted by CTRL+c.

• Issue #12216: Allow unexpected EOF errors to happen on any line of the file.

• Issue #12199: The TryExcept and TryFinally and AST nodes have been unified into a Try node.

• Issue #9670: Increase the default stack size for secondary threads on Mac OS X and FreeBSD to reduce the chances of a crash instead of a “maximum recursion depth” RuntimeError exception. (patch by Ronald Oussoren)

• Issue #12106: The use of the multiple-with shorthand syntax is now reflected in the AST.

• Issue #12190: Try to use the same filename object when compiling unmarshalling a code objects in the same file.

• Issue #12166: Move implementations of dir() specialized for various types into the __dir__() methods of those types.

• Issue #5715: In socketserver, close the server socket in the child process.

• Correct lookup of __dir__ on objects. Among other things, this causes errors besides AttributeError found on lookup to be propagated.

• Issue #12060: Use sig_atomic_t type and volatile keyword in the signal module. Patch written by Charles-François Natali.

• Issue #1746656: Added the if_nameindex, if_indextoname, if_nametoindex methods to the socket module.

• Issue #12044: Fixed subprocess.Popen when used as a context manager to wait for the process to end when exiting the context to avoid unintentionally leaving zombie processes around.

• Issue #1195: Fix input() if it is interrupted by CTRL+d and then CTRL+c, clear the end-of-file indicator after CTRL+d.

• Issue #1856: Avoid crashes and lockups when daemon threads run while the interpreter is shutting down; instead, these threads are now killed when they try to take the GIL.

• Issue #9756: When calling a method descriptor or a slot wrapper descriptor, the check of the object type doesn’t read the __class__ attribute anymore. Fix a crash if a class override its __class__ attribute (e.g. a proxy of the str type). Patch written by Andreas Stührk.

• Issue #10517: After fork(), reinitialize the TLS used by the PyGILState_* APIs, to avoid a crash with the pthread implementation in RHEL 5. Patch by Charles-François Natali.

• Issue #10914: Initialize correctly the filesystem codec when creating a new subinterpreter to fix a bootstrap issue with codecs implemented in Python, as the ISO-8859-15 codec.

• Issue #11918: OS/2 and VMS are no more supported because of the lack of maintainer.

• Issue #6780: fix starts/endswith error message to mention that tuples are accepted too.

• Issue #5057: fix a bug in the peepholer that led to non-portable pyc files between narrow and wide builds while optimizing BINARY_SUBSCR on non-BMP chars (e.g. “U00012345”[0]).

• Issue #11845: Fix typo in rangeobject.c that caused a crash in compute_slice_indices. Patch by Daniel Urban.

• Issue #5673: Added a timeout keyword argument to subprocess.Popen.wait, subprocess.Popen.communicated, subprocess.call, subprocess.check_call, and subprocess.check_output. If the blocking operation takes more than timeout seconds, the subprocess.TimeoutExpired exception is raised.

• Issue #11650: PyOS_StdioReadline() retries fgets() if it was interrupted (EINTR), for example if the program is stopped with CTRL+z on Mac OS X. Patch written by Charles-Francois Natali.

• Issue #9319: Include the filename in “Non-UTF8 code ...” syntax error.

• Issue #10785: Store the filename as Unicode in the Python parser.

• Issue #11619: _PyImport_LoadDynamicModule() doesn’t encode the path to bytes on Windows.

• Issue #10998: Remove mentions of -Q, sys.flags.division_warning and Py_DivisionWarningFlag left over from Python 2.

• Issue #11244: Remove an unnecessary peepholer check that was preventing negative zeros from being constant-folded properly.

• Issue #11395: io.FileIO().write() clamps the data length to 32,767 bytes on Windows if the file is a TTY to workaround a Windows bug. The Windows console returns an error (12: not enough space error) on writing into stdout if stdout mode is binary and the length is greater than 66,000 bytes (or less, depending on heap usage).

• Issue #11320: fix bogus memory management in Modules/getpath.c, leading to a possible crash when calling Py_SetPath().

• Issue #11432: A bug was introduced in subprocess.Popen on posix systems with 3.2.0 where the stdout or stderr file descriptor being the same as the stdin file descriptor would raise an exception. webbrowser.open would fail. fixed.

• Issue #9856: Change object.__format__ with a non-empty format string to be a DeprecationWarning. In 3.2 it was a PendingDeprecationWarning. In 3.4 it will be a TypeError.

• Issue #11244: The peephole optimizer is now able to constant-fold arbitrarily complex expressions. This also fixes a 3.2 regression where operations involving negative numbers were not constant-folded.

• Issue #11450: Don’t truncate hg version info in Py_GetBuildInfo() when there are many tags (e.g. when using mq). Patch by Nadeem Vawda.

• Issue #11335: Fixed a memory leak in list.sort when the key function throws an exception.

• Issue #8923: When a string is encoded to UTF-8 in strict mode, the result is cached into the object. Examples: str.encode(), str.encode(‘utf-8’), PyUnicode_AsUTF8String() and PyUnicode_AsEncodedString(unicode, “utf-8”, NULL).

• Issue #10829: Refactor PyUnicode_FromFormat(), use the same function to parse the format string in the 3 steps, fix crashs on invalid format strings.

• Issue #13007: whichdb should recognize gdbm 1.9 magic numbers.

• Issue #11286: Raise a ValueError from calling PyMemoryView_FromBuffer with a buffer struct having a NULL data pointer.

• Issue #11272: On Windows, input() strips ‘r’ (and not only ‘n’), and sys.stdin uses universal newline (replace ‘rn’ by ‘n’).

• Issue #11828: startswith and endswith now accept None as slice index. Patch by Torsten Becker.

• Issue #11168: Remove filename debug variable from PyEval_EvalFrameEx(). It encoded the Unicode filename to UTF-8, but the encoding fails on undecodable filename (on surrogate characters) which raises an unexpected UnicodeEncodeError on recursion limit.

• Issue #11187: Remove bootstrap code (use ASCII) of PyUnicode_AsEncodedString(), it was replaced by a better fallback (use the locale encoding) in PyUnicode_EncodeFSDefault().

• Check for NULL result in PyType_FromSpec.

• Issue #10516: New copy() and clear() methods for lists and bytearrays.

• Issue #11386: bytearray.pop() now throws IndexError when the bytearray is empty, instead of OverflowError.

• Issue #12380: The rjust, ljust and center methods of bytes and bytearray now accept a bytearray argument.

Library

• Issue #14195: An issue that caused weakref.WeakSet instances to incorrectly return True for a WeakSet instance ‘a’ in both ‘a < a’ and ‘a > a’ has been fixed.
• Issue #14166: Pickler objects now have an optional dispatch_table attribute which allows to set custom per-pickler reduction functions. Patch by sbt.
• Issue #14177: marshal.loads() now raises TypeError when given an unicode string. Patch by Guilherme Gonçalves.
• Issue #13550: Remove the debug machinery from the threading module: remove verbose arguments from all threading classes and functions.
• Issue #14159: Fix the len() of weak containers (WeakSet, WeakKeyDictionary, WeakValueDictionary) to return a better approximation when some objects are dead or dying. Moreover, the implementation is now O(1) rather than O(n).
• Issue #11841: Fix comparison bug with ‘rc’ versions in packaging.version. Patch by Filip Gruszczyński.
• Issue #6884: Fix long-standing bugs with MANIFEST.in parsing in distutils on Windows. Also fixed in packaging.
• Issue #8033: sqlite3: Fix 64-bit integer handling in user functions on 32-bit architectures. Initial patch by Philippe Devalkeneer.
• HTMLParser is now able to handle slashes in the start tag.
• Issue #13641: Decoding functions in the base64 module now accept ASCII-only unicode strings. Patch by Catalin Iacob.
• Issue #14043: Speed up importlib’s _FileFinder by at least 8x, and add a new importlib.invalidate_caches() function.
• Issue #14001: CVE-2012-0845: xmlrpc: Fix an endless loop in SimpleXMLRPCServer upon malformed POST request.
• Issue #13961: Move importlib over to using os.replace() for atomic renaming.
• Do away with ambiguous level values (as suggested by PEP 328) in importlib.__import__() by raising ValueError when level < 0.
• Issue #2489: pty.spawn could consume 100% cpu when it encountered an EOF.
• Issue #13014: Fix a possible reference leak in SSLSocket.getpeercert().
• Issue #13777: Add PF_SYSTEM sockets on OS X. Patch by Michael Goderbauer.
• Issue #13015: Fix a possible reference leak in defaultdict.__repr__. Patch by Suman Saha.
• Issue #1326113: distutils’ and packaging’s build_ext commands option now correctly parses multiple values (separated by whitespace or commas) given to their –libraries option.
• Issue #10287: nntplib now queries the server’s CAPABILITIES first before sending MODE READER, and only sends it if not already in READER mode. Patch by Hynek Schlawack.
• Issue #13993: HTMLParser is now able to handle broken end tags when strict=False.
• Issue #13930: lib2to3 now supports writing converted output files to another directory tree as well as copying unchanged files and altering the file suffix.
• Issue #9750: Fix sqlite3.Connection.iterdump on tables and fields with a name that is a keyword or contains quotes. Patch by Marko Kohtala.
• Issue #10287: nntplib now queries the server’s CAPABILITIES again after authenticating (since the result may change, according to RFC 4643). Patch by Hynek Schlawack.
• Issue #13590: On OS X 10.7 and 10.6 with Xcode 4.2, building Distutils-based packages with C extension modules may fail because Apple has removed gcc-4.2, the version used to build python.org 64-bit/32-bit Pythons. If the user does not explicitly override the default C compiler by setting the CC environment variable, Distutils will now attempt to compile extension modules with clang if gcc-4.2 is required but not found. Also as a convenience, if the user does explicitly set CC, substitute its value as the default compiler in the Distutils LDSHARED configuration variable for OS X. (Note, the python.org 32-bit-only Pythons use gcc-4.0 and the 10.4u SDK, neither of which are available in Xcode 4. This change does not attempt to override settings to support their use with Xcode 4.)
• Issue #13960: HTMLParser is now able to handle broken comments when strict=False.
• When ‘’ is a path (e.g. in sys.path), make sure __file__ uses the current working directory instead of ‘’ in importlib.
• Issue #13609: Add two functions to query the terminal size: os.get_terminal_size (low level) and shutil.get_terminal_size (high level). Patch by Zbigniew Jędrzejewski-Szmek.
• Issue #13845: On Windows, time.time() now uses GetSystemTimeAsFileTime() instead of ftime() to have a resolution of 100 ns instead of 1 ms (the clock accuracy is between 0.5 ms and 15 ms).
• Issue #13846: Add time.monotonic(), monotonic clock.
• Issue #8184: multiprocessing: On Windows, don’t set SO_REUSEADDR on Connection sockets, and set FILE_FLAG_FIRST_PIPE_INSTANCE on named pipes, to make sure two listeners can’t bind to the same socket/pipe (or any existing socket/pipe).
• Issue #10811: Fix recursive usage of cursors. Instead of crashing, raise a ProgrammingError now.
• Issue #13734: Add os.fwalk(), a directory walking function yielding file descriptors.
• Issue #2945: Make the distutils upload command aware of bdist_rpm products.
• Issue #13712: pysetup create should not convert package_data to extra_files.
• Issue #11805: package_data in setup.cfg should allow more than one value.
• Issue #13676: Handle strings with embedded zeros correctly in sqlite3.
• Issue #8828: Add new function os.replace(), for cross-platform renaming with overwriting.
• Issue #13848: open() and the FileIO constructor now check for NUL characters in the file name. Patch by Hynek Schlawack.
• Issue #13806: The size check in audioop decompression functions was too strict and could reject valid compressed data. Patch by Oleg Plakhotnyuk.
• Issue #13812: When a multiprocessing Process child raises an exception, flush stderr after printing the exception traceback.
• Issue #13885: CVE-2011-3389: the _ssl module would always disable the CBC IV attack countermeasure.
• Issue #13847: time.localtime() and time.gmtime() now raise an OSError instead of ValueError on failure. time.ctime() and time.asctime() now raises an OSError if localtime() failed. time.clock() now raises a RuntimeError if the processor time used is not available or its value cannot be represented
• Issue #13772: In os.symlink() under Windows, do not try to guess the link target’s type (file or directory). The detection was buggy and made the call non-atomic (therefore prone to race conditions).
• Issue #6631: Disallow relative file paths in urllib urlopen methods.
• Issue #13722: Avoid silencing ImportErrors when initializing the codecs registry.
• Issue #13781: Fix GzipFile bug that caused an exception to be raised when opening for writing using a fileobj returned by os.fdopen().
• Issue #13803: Under Solaris, distutils doesn’t include bitness in the directory name.
• Issue #10278: Add time.wallclock() function, monotonic clock.
• Issue #13809: Fix regression where bz2 module wouldn’t work when threads are disabled. Original patch by Amaury Forgeot d’Arc.
• Issue #13589: Fix some serialization primitives in the aifc module. Patch by Oleg Plakhotnyuk.
• Issue #13642: Unquote before b64encoding user:password during Basic Authentication. Patch contributed by Joonas Kuorilehto.
• Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor. The hang would occur when retrieving the result of a scheduled future after the executor had been shut down.
• Issue #13502: threading: Fix a race condition in Event.wait() that made it return False when the event was set and cleared right after.
• Issue #9993: When the source and destination are on different filesystems, and the source is a symlink, shutil.move() now recreates a symlink on the destination instead of copying the file contents. Patch by Jonathan Niehof and Hynek Schlawack.
• Issue #12926: Fix a bug in tarfile’s link extraction.
• Issue #13696: Fix the 302 Relative URL Redirection problem.
• Issue #13636: Weak ciphers are now disabled by default in the ssl module (except when SSLv2 is explicitly asked for).
• Issue #12715: Add an optional symlinks argument to shutil functions (copyfile, copymode, copystat, copy, copy2). When that parameter is true, symlinks aren’t dereferenced and the operation instead acts on the symlink itself (or creates one, if relevant). Patch by Hynek Schlawack.
• Add a flags parameter to select.epoll.
• Issue #13626: Add support for SSL Diffie-Hellman key exchange, through the SSLContext.load_dh_params() method and the ssl.OP_SINGLE_DH_USE option.
• Issue #11006: Don’t issue low level warning in subprocess when pipe2() fails.
• Issue #13620: Support for Chrome browser in webbrowser. Patch contributed by Arnaud Calmettes.
• Issue #11829: Fix code execution holes in inspect.getattr_static for metaclasses with metaclasses. Patch by Andreas Stührk.
• Issue #12708: Add starmap() and starmap_async() methods (similar to itertools.starmap()) to multiprocessing.Pool. Patch by Hynek Schlawack.
• Issue #1785: Fix inspect and pydoc with misbehaving descriptors.
• Issue #13637: “a2b” functions in the binascii module now accept ASCII-only unicode strings.
• Issue #13634: Add support for querying and disabling SSL compression.
• Issue #13627: Add support for SSL Elliptic Curve-based Diffie-Hellman key exchange, through the SSLContext.set_ecdh_curve() method and the ssl.OP_SINGLE_ECDH_USE option.
• Issue #13635: Add ssl.OP_CIPHER_SERVER_PREFERENCE, so that SSL servers choose the cipher based on their own preferences, rather than on the client’s.
• Issue #11813: Fix inspect.getattr_static for modules. Patch by Andreas Stührk.
• Issue #7502: Fix equality comparison for DocTestCase instances. Patch by Cédric Krier.
• Issue #11870: threading: Properly reinitialize threads internal locks and condition variables to avoid deadlocks in child processes.
• Issue #8035: urllib: Fix a bug where the client could remain stuck after a redirection or an error.
• Issue #13560: os.strerror() now uses the current locale encoding instead of UTF-8.
• Issue #8373: The filesystem path of AF_UNIX sockets now uses the filesystem encoding and the surrogateescape error handler, rather than UTF-8. Patch by David Watson.
• Issue #10350: Read and save errno before calling a function which might overwrite it. Original patch by Hallvard B Furuseth.
• Issue #11610: Introduce a more general way to declare abstract properties.
• Issue #13591: A bug in importlib has been fixed that caused import_module to load a module twice.
• Issue #13449 sched.scheduler.run() method has a new “blocking” parameter which when set to False makes run() execute the scheduled events due to expire soonest (if any) and then return. Patch by Giampaolo Rodolà.
• Issue #8684 sched.scheduler class can be safely used in multi-threaded environments. Patch by Josiah Carlson and Giampaolo Rodolà.
• Alias resource.error to OSError ala PEP 3151.
• Issue #5689: Add support for lzma compression to the tarfile module.
• Issue #13248: Turn 3.2’s PendingDeprecationWarning into 3.3’s DeprecationWarning. It covers ‘cgi.escape’, ‘importlib.abc.PyLoader’, ‘importlib.abc.PyPycLoader’, ‘nntplib.NNTP.xgtitle’, ‘nntplib.NNTP.xpath’, and private attributes of ‘smtpd.SMTPChannel’.
• Issue #5905, #13560: time.strftime() is now using the current locale encoding, instead of UTF-8, if the wcsftime() function is not available.
• Issue #13464: Add a readinto() method to http.client.HTTPResponse. Patch by Jon Kuhn.
• tarfile.py: Correctly detect bzip2 compressed streams with blocksizes other than 900k.
• Issue #13439: Fix many errors in turtle docstrings.
• Issue #6715: Add a module ‘lzma’ for compression using the LZMA algorithm. Thanks to Per Øyvind Karlsen for the initial implementation.
• Issue #13487: Make inspect.getmodule robust against changes done to sys.modules while it is iterating over it.
• Issue #12618: Fix a bug that prevented py_compile from creating byte compiled files in the current directory. Initial patch by Sjoerd de Vries.
• Issue #13444: When stdout has been closed explicitly, we should not attempt to flush it at shutdown and print an error.
• Issue #12567: The curses module uses Unicode functions for Unicode arguments when it is linked to the ncurses library. It encodes also Unicode strings to the locale encoding instead of UTF-8.
• Issue #12856: Ensure child processes do not inherit the parent’s random seed for filename generation in the tempfile module. Patch by Brian Harring.
• Issue #9957: SpooledTemporaryFile.truncate() now accepts an optional size parameter, as other file-like objects. Patch by Ryan Kelly.
• Issue #13458: Fix a memory leak in the ssl module when decoding a certificate with a subjectAltName. Patch by Robert Xiao.
• Issue #13415: os.unsetenv() doesn’t ignore errors anymore.
• Issue #13245: sched.scheduler class constructor’s timefunc and delayfunct parameters are now optional. scheduler.enter and scheduler.enterabs methods gained a new kwargs parameter. Patch contributed by Chris Clark.
• Issue #12328: Under Windows, refactor handling of Ctrl-C events and make _multiprocessing.win32.WaitForMultipleObjects interruptible when the wait_flag parameter is false. Patch by sbt.
• Issue #13322: Fix BufferedWriter.write() to ensure that BlockingIOError is raised when the wrapped raw file is non-blocking and the write would block. Previous code assumed that the raw write() would raise BlockingIOError, but RawIOBase.write() is defined to returned None when the call would block. Patch by sbt.
• Issue #13358: HTMLParser now calls handle_data only once for each CDATA.
• Issue #4147: minidom’s toprettyxml no longer adds whitespace around a text node when it is the only child of an element. Initial patch by Dan Kenigsberg.
• Issue #13374: The Windows bytes API has been deprecated in the os module. Use Unicode filenames instead of bytes filenames to not depend on the ANSI code page anymore and to support any filename.
• Issue #13297: Use bytes type to send and receive binary data through XMLRPC.
• Issue #6397: Support “/dev/poll” polling objects in select module, under Solaris & derivatives.
• Issues #1745761, #755670, #13357, #12629, #1200313: HTMLParser now correctly handles non-valid attributes, including adjacent and unquoted attributes.
• Issue #13193: Fix distutils.filelist.FileList and packaging.manifest.Manifest under Windows.
• Issue #13384: Remove unnecessary __future__ import in Lib/random.py
• Issue #13149: Speed up append-only StringIO objects.
• Issue #13373: multiprocessing.Queue.get() could sometimes block indefinitely when called with a timeout. Patch by Arnaud Ysmal.
• Issue #13254: Fix Maildir initialization so that maildir contents are read correctly.
• Issue #3067: locale.setlocale() now raises TypeError if the second argument is an invalid iterable. Its documentation and docstring were also updated. Initial patch by Jyrki Pulliainen.
• Issue #13140: Fix the daemon_threads attribute of ThreadingMixIn.
• Issue #13339: Fix compile error in posixmodule.c due to missing semicolon. Thanks to Robert Xiao.
• Byte compilation in packaging is now isolated from the calling Python -B or -O options, instead of being disallowed under -B or buggy under -O.
• Issue #10570: curses.putp() and curses.tparm() are now expecting a byte string, instead of a Unicode string.
• Issue #13295: http.server now produces valid HTML 4.01 strict.
• Issue #2892: preserve iterparse events in case of SyntaxError.
• Issue #13287: urllib.request and urllib.error now contains an __all__ attribute to expose only relevant classes and functions. Patch by Florent Xicluna.
• Issue #670664: Fix HTMLParser to correctly handle the content of <script>...</script> and <style>...</style>.
• Issue #10817: Fix urlretrieve function to raise ContentTooShortError even when reporthook is None. Patch by Jyrki Pulliainen.
• Fix the xmlrpc.client user agent to return something similar to urllib.request user agent: “Python-xmlrpc/3.3”.
• Issue #13293: Better error message when trying to marshal bytes using xmlrpc.client.
• Issue #13291: NameError in xmlrpc package.
• Issue #13258: Use callable() built-in in the standard library.
• Issue #13273: fix a bug that prevented HTMLParser to properly detect some tags when strict=False.
• Issue #11183: Add finer-grained exceptions to the ssl module, so that you don’t have to inspect the exception’s attributes in the common case.
• Issue #13216: Add cp65001 codec, the Windows UTF-8 (CP_UTF8).
• Issue #13226: Add RTLD_xxx constants to the os module. These constants can be used with sys.setdlopenflags().
• Issue #10278: Add clock_getres(), clock_gettime() and CLOCK_xxx constants to the time module. time.clock_gettime(time.CLOCK_MONOTONIC) provides a monotonic clock
• Issue #10332: multiprocessing: fix a race condition when a Pool is closed before all tasks have completed.
• Issue #13255: wrong docstrings in array module.
• Issue #8540: Remove deprecated Context._clamp attribute in Decimal module.
• Issue #13235: Added DeprecationWarning to logging.warn() method and function.
• Issue #9168: now smtpd is able to bind privileged port.
• Issue #12529: fix cgi.parse_header issue on strings with double-quotes and semicolons together. Patch by Ben Darnell and Petri Lehtinen.
• Issue #13227: functools.lru_cache() now has a option to distinguish calls with different argument types.
• Issue #6090: zipfile raises a ValueError when a document with a timestamp earlier than 1980 is provided. Patch contributed by Petri Lehtinen.
• Issue #13150: sysconfig no longer parses the Makefile and config.h files when imported, instead doing it at build time. This makes importing sysconfig faster and reduces Python startup time by 20%.
• Issue #12448: smtplib now flushes stdout while running python -m smtplib in order to display the prompt correctly.
• Issue #12454: The mailbox module is now using ASCII, instead of the locale encoding, to read and write .mh_sequences files.
• Issue #13194: zlib.compressobj().copy() and zlib.decompressobj().copy() are now available on Windows.
• Issue #1673007: urllib.request now supports HEAD request via new method argument. Patch contributions by David Stanek, Patrick Westerhoff and Ezio Melotti.
• Issue #12386: packaging does not fail anymore when writing the RESOURCES file.
• Issue #13158: Fix decoding and encoding of GNU tar specific base-256 number fields in tarfile.
• Issue #13025: mimetypes is now reading MIME types using the UTF-8 encoding, instead of the locale encoding.
• Issue #10653: On Windows, use strftime() instead of wcsftime() because wcsftime() doesn’t format time zone correctly.
• Issue #13150: The tokenize module doesn’t compile large regular expressions at startup anymore.
• Issue #11171: Fix distutils.sysconfig.get_makefile_filename when Python was configured with different prefix and exec-prefix.
• Issue #11254: Teach distutils and packaging to compile .pyc and .pyo files in PEP 3147-compliant __pycache__ directories.
• Issue #7367: Fix pkgutil.walk_paths to skip directories whose contents cannot be read.
• Issue #3163: The struct module gets new format characters ‘n’ and ‘N’ supporting C integer types ssize_t and size_t, respectively.
• Issue #13099: Fix sqlite3.Cursor.lastrowid under a Turkish locale. Reported and diagnosed by Thomas Kluyver.
• Issue #13087: BufferedReader.seek() now always raises UnsupportedOperation if the underlying raw stream is unseekable, even if the seek could be satisfied using the internal buffer. Patch by John O’Connor.
• Issue #7689: Allow pickling of dynamically created classes when their metaclass is registered with copyreg. Patch by Nicolas M. Thiéry and Craig Citro.
• Issue #13034: When decoding some SSL certificates, the subjectAltName extension could be unreported.
• Issue #12306: Expose the runtime version of the zlib C library as a constant, ZLIB_RUNTIME_VERSION, in the zlib module. Patch by Torsten Landschoff.
• Issue #12959: Add collections.ChainMap to collections.__all__.
• Issue #8933: distutils’ PKG-INFO files and packaging’s METADATA files will now correctly report Metadata-Version: 1.1 instead of 1.0 if a Classifier or Download-URL field is present.
• Issue #12567: Add curses.unget_wch() function. Push a character so the next get_wch() will return it.
• Issue #9561: distutils and packaging now writes egg-info files using UTF-8, instead of the locale encoding.
• Issue #8286: The distutils command sdist will print a warning message instead of crashing when an invalid path is given in the manifest template.
• Issue #12841: tarfile unnecessarily checked the existence of numerical user and group ids on extraction. If one of them did not exist the respective id of the current user (i.e. root) was used for the file and ownership information was lost.
• Issue #12888: Fix a bug in HTMLParser.unescape that prevented it to escape more than 128 entities. Patch by Peter Otten.
• Issue #12878: Expose a __dict__ attribute on io.IOBase and its subclasses.
• Issue #12494: On error, call(), check_call(), check_output() and getstatusoutput() functions of the subprocess module now kill the process, read its status (to avoid zombis) and close pipes.
• Issue #12720: Expose low-level Linux extended file attribute functions in os.
• Issue #10946: The distutils commands bdist_dumb, bdist_wininst and bdist_msi now respect a –skip-build option given to bdist. The packaging commands were fixed too.
• Issue #12847: Fix a crash with negative PUT and LONG_BINPUT arguments in the C pickle implementation.
• Issue #11564: Avoid crashes when trying to pickle huge objects or containers (more than 2**31 items). Instead, in most cases, an OverflowError is raised.
• Issue #12287: Fix a stack corruption in ossaudiodev module when the FD is greater than FD_SETSIZE.
• Issue #12839: Fix crash in zlib module due to version mismatch. Fix by Richard M. Tew.
• Issue #9923: The mailcap module now correctly uses the platform path separator for the MAILCAP environment variable on non-POSIX platforms.
• Issue #12835: Follow up to #6560 that unconditionally prevents use of the unencrypted sendmsg/recvmsg APIs on SSL wrapped sockets. Patch by David Watson.
• Issue #12803: SSLContext.load_cert_chain() now accepts a password argument to be used if the private key is encrypted. Patch by Adam Simpkins.
• Issue #11657: Fix sending file descriptors over 255 over a multiprocessing Pipe.
• Issue #12811: tabnanny.check() now promptly closes checked files. Patch by Anthony Briggs.
• Issue #6560: The sendmsg/recvmsg API is now exposed by the socket module when provided by the underlying platform, supporting processing of ancillary data in pure Python code. Patch by David Watson and Heiko Wundram.
• Issue #12326: On Linux, sys.platform doesn’t contain the major version anymore. It is now always ‘linux’, instead of ‘linux2’ or ‘linux3’ depending on the Linux version used to build Python.
• Issue #12213: Fix a buffering bug with interleaved reads and writes that could appear on BufferedRandom streams.
• Issue #12778: Reduce memory consumption when JSON-encoding a large container of many small objects.
• Issue #12650: Fix a race condition where a subprocess.Popen could leak resources (FD/zombie) when killed at the wrong time.
• Issue #12744: Fix inefficient representation of integers between 2**31 and 2**63 on systems with a 64-bit C “long”.
• Issue #12646: Add an ‘eof’ attribute to zlib.Decompress, to make it easier to detect truncated input streams.
• Issue #11513: Fix exception handling tarfile.TarFile.gzopen() when the file cannot be opened.
• Issue #12687: Fix a possible buffering bug when unpickling text mode (protocol 0, mostly) pickles.
• Issue #10087: Fix the html output format of the calendar module.
• Issue #13121: add support for inplace math operators to collections.Counter.
• Add support for unary plus and unary minus to collections.Counter.
• Issue #12683: urlparse updated to include svn as schemes that uses relative paths. (svn from 1.5 onwards support relative path).
• Issue #12655: Expose functions from sched.h in the os module: sched_yield(), sched_setscheduler(), sched_getscheduler(), sched_setparam(), sched_get_min_priority(), sched_get_max_priority(), sched_rr_get_interval(), sched_getaffinity(), sched_setaffinity().
• Add ThreadError to threading.__all__.
• Issues #11104, #8688: Fix the behavior of distutils’ sdist command with manually-maintained MANIFEST files.
• Issue #11281: smtplib.STMP gets source_address parameter, which adds the ability to bind to specific source address on a machine with multiple interfaces. Patch by Paulo Scardine.
• Issue #12464: tempfile.TemporaryDirectory.cleanup() should not follow symlinks: fix it. Patch by Petri Lehtinen.
• Issue #8887: “pydoc somebuiltin.somemethod” (or help(‘somebuiltin.somemethod’) in Python code) now finds the doc of the method.
• Issue #10968: Remove indirection in threading. The public names (Event, Condition, etc.) used to be factory functions returning instances of hidden classes (_Event, _Condition, etc.), because (if Guido recalls correctly) this code pre-dates the ability to subclass extension types. It is now possible to inherit from these classes, without having to import the private underscored names like multiprocessing did.
• Issue #9723: Add shlex.quote functions, to escape filenames and command lines.
• Issue #12603: Fix pydoc.synopsis() on files with non-negative st_mtime.
• Issue #12514: Use try/finally to assure the timeit module restores garbage collections when it is done.
• Issue #12607: In subprocess, fix issue where if stdin, stdout or stderr is given as a low fd, it gets overwritten.
• Issue #12576: Fix urlopen behavior on sites which do not send (or obfuscate) a Connection: close header.
• Issue #12560: Build libpython.so on OpenBSD. Patch by Stefan Sperling.
• Issue #1813: Fix codec lookup under Turkish locales.
• Issue #12591: Improve support of “universal newlines” in the subprocess module: the piped streams can now be properly read from or written to.
• Issue #12591: Allow io.TextIOWrapper to work with raw IO objects (without a read1() method), and add a write_through parameter to mandate unbuffered writes.
• Issue #10883: Fix socket leaks in urllib.request when using FTP.
• Issue #12592: Make Python build on OpenBSD 5 (and future major releases).
• Issue #12372: POSIX semaphores are broken on AIX: don’t use them.
• Issue #12551: Provide a get_channel_binding() method on SSL sockets so as to get channel binding data for the current SSL session (only the “tls-unique” channel binding is implemented). This allows the implementation of certain authentication mechanisms such as SCRAM-SHA-1-PLUS. Patch by Jacek Konieczny.
• Issue #665194: email.utils now has format_datetime and parsedate_to_datetime functions, allowing for round tripping of RFC2822 format dates.
• Issue #12571: Add a plat-linux3 directory mirroring the plat-linux2 directory, so that “import DLFCN” and other similar imports work on Linux 3.0.
• Issue #7484: smtplib no longer puts <> around addresses in VRFY and EXPN commands; they aren’t required and in fact postfix doesn’t support that form.
• Issue #12273: Remove ast.__version__. AST changes can be accounted for by checking sys.version_info or sys._mercurial.
• Silence spurious “broken pipe” tracebacks when shutting down a ProcessPoolExecutor.
• Fix potential resource leaks in concurrent.futures.ProcessPoolExecutor by joining all queues and processes when shutdown() is called.
• Issue #11603: Fix a crash when __str__ is rebound as __repr__. Patch by Andreas Stührk.
• Issue #11321: Fix a crash with multiple imports of the _pickle module when embedding Python. Patch by Andreas Stührk.
• Issue #6755: Add get_wch() method to curses.window class. Patch by Iñigo Serna.
• Add cgi.closelog() function to close the log file.
• Issue #12502: asyncore: fix polling loop with AF_UNIX sockets.
• Issue #4376: ctypes now supports nested structures in a endian different than the parent structure. Patch by Vlad Riscutia.
• Raise ValueError when attempting to set the _CHUNK_SIZE attribute of a TextIOWrapper to a huge value, not TypeError.
• Issue #12504: Close file handles in a timely manner in packaging.database. This fixes a bug with the remove (uninstall) feature on Windows.
• Issues #12169 and #10510: Factor out code used by various packaging commands to make HTTP POST requests, and make sure it uses CRLF.
• Issue #12016: Multibyte CJK decoders now resynchronize faster. They only ignore the first byte of an invalid byte sequence. For example, b’xffn’.decode(‘gb2312’, ‘replace’) gives ‘ufffdn’ instead of ‘ufffd’.
• Issue #12459: time.sleep() now raises a ValueError if the sleep length is negative, instead of an infinite sleep on Windows or raising an IOError on Linux for example, to have the same behaviour on all platforms.
• Issue #12451: pydoc: html_getfile() now uses tokenize.open() to support Python scripts using a encoding different than UTF-8 (read the coding cookie of the script).
• Issue #12493: subprocess: Popen.communicate() now also handles EINTR errors if the process has only one pipe.
• Issue #12467: warnings: fix a race condition if a warning is emitted at shutdown, if globals()[‘__file__’] is None.
• Issue #12451: pydoc: importfile() now opens the Python script in binary mode, instead of text mode using the locale encoding, to avoid encoding issues.
• Issue #12451: runpy: run_path() now opens the Python script in binary mode, instead of text mode using the locale encoding, to support other encodings than UTF-8 (scripts using the coding cookie).
• Issue #12451: xml.dom.pulldom: parse() now opens files in binary mode instead of the text mode (using the locale encoding) to avoid encoding issues.
• Issue #12147: Adjust the new-in-3.2 smtplib.send_message method for better conformance to the RFCs: correctly handle Sender and Resent- headers.
• Issue #12352: Fix a deadlock in multiprocessing.Heap when a block is freed by the garbage collector while the Heap lock is held.
• Issue #12462: time.sleep() now immediately calls the (Python) signal handler if it is interrupted by a signal, instead of having to wait until the next instruction.
• Issue #12442: new shutil.disk_usage function, providing total, used and free disk space statistics.
• Issue #12451: The XInclude default loader of xml.etree now decodes files from UTF-8 instead of the locale encoding if the encoding is not specified. It now also opens XML files for the parser in binary mode instead of the text mode to avoid encoding issues.
• Issue #12451: doctest.debug_script() doesn’t create a temporary file anymore to avoid encoding issues.
• Issue #12451: pydoc.synopsis() now reads the encoding cookie if available, to read the Python script from the right encoding.
• Issue #12451: distutils now opens the setup script in binary mode to read the encoding cookie, instead of opening it in UTF-8.
• Issue #9516: On Mac OS X, change Distutils to no longer globally attempt to check or set the MACOSX_DEPLOYMENT_TARGET environment variable for the interpreter process. This could cause failures in non-Distutils subprocesses and was unreliable since tests or user programs could modify the interpreter environment after Distutils set it. Instead, have Distutils set the deployment target only in the environment of each build subprocess. It is still possible to globally override the default by setting MACOSX_DEPLOYMENT_TARGET before launching the interpreter; its value must be greater or equal to the default value, the value with which the interpreter was built. Also, implement the same handling in packaging.
• Issue #12422: In the copy module, don’t store objects that are their own copy in the memo dict.
• Issue #12303: Add sigwaitinfo() and sigtimedwait() to the signal module.
• Issue #12404: Remove C89 incompatible code from mmap module. Patch by Akira Kitada.
• Issue #1874: email now detects and reports as a defect the presence of any CTE other than 7bit, 8bit, or binary on a multipart.
• Issue #12383: Fix subprocess module with env={}: don’t copy the environment variables, start with an empty environment.
• Issue #11637: Fix support for importing packaging setup hooks from the project directory.
• Issue #6771: Moved the curses.wrapper function from the single-function wrapper module into __init__, eliminating the module. Since __init__ was already importing the function to curses.wrapper, there is no API change.
• Issue #11584: email.header.decode_header no longer fails if the header passed to it is a Header object, and Header/make_header no longer fail if given binary unknown-8bit input.
• Issue #11700: mailbox proxy object close methods can now be called multiple times without error.
• Issue #11767: Correct file descriptor leak in mailbox’s __getitem__ method.
• Issue #12133: AbstractHTTPHandler.do_open() of urllib.request closes the HTTP connection if its getresponse() method fails with a socket error. Patch written by Ezio Melotti.
• Issue #12240: Allow multiple setup hooks in packaging’s setup.cfg files. Original patch by Erik Bray.
• Issue #9284: Allow inspect.findsource() to find the source of doctest functions.
• Issue #11595: Fix assorted bugs in packaging.util.cfg_to_args, a compatibility helper for the distutils-packaging transition. Original patch by Erik Bray.
• Issue #12287: In ossaudiodev, check that the device isn’t closed in several methods.
• Issue #12009: Fixed regression in netrc file comment handling.
• Issue #12246: Warn and fail when trying to install a third-party project from an uninstalled Python (built in a source checkout). Original patch by Tshepang Lekhonkhobe.
• Issue #10694: zipfile now ignores garbage at the end of a zipfile.
• Issue #12283: Fixed regression in smtplib quoting of leading dots in DATA.
• Issue #10424: Argparse now includes the names of the missing required arguments in the missing arguments error message.
• Issue #12168: SysLogHandler now allows NUL termination to be controlled using a new ‘append_nul’ attribute on the handler.
• Issue #11583: Speed up os.path.isdir on Windows by using GetFileAttributes instead of os.stat.
• Issue #12021: Make mmap’s read() method argument optional. Patch by Petri Lehtinen.
• Issue #9205: concurrent.futures.ProcessPoolExecutor now detects killed children and raises BrokenProcessPool in such a situation. Previously it would reliably freeze/deadlock.
• Issue #12040: Expose a new attribute sentinel on instances of multiprocessing.Process. Also, fix Process.join() to not use polling anymore, when given a timeout.
• Issue #11893: Remove obsolete internal wrapper class SSLFakeFile in the smtplib module. Patch by Catalin Iacob.
• Issue #12080: Fix a Decimal.power() case that took an unreasonably long time to compute.
• Issue #12221: Remove __version__ attributes from pyexpat, pickle, tarfile, pydoc, tkinter, and xml.parsers.expat. This were useless version constants left over from the Mercurial transition
• Named tuples now work correctly with vars().
• Issue #12085: Fix an attribute error in subprocess.Popen destructor if the constructor has failed, e.g. because of an undeclared keyword argument. Patch written by Oleg Oshmyan.
• Issue #12028: Make threading._get_ident() public, rename it to threading.get_ident() and document it. This function was already used using _thread.get_ident().
• Issue #12171: IncrementalEncoder.reset() of CJK codecs (multibytecodec) calls encreset() instead of decreset().
• Issue #12218: Removed wsgiref.egg-info.
• Issue #12196: Add pipe2() to the os module.
• Issue #985064: Make plistlib more resilient to faulty input plists. Patch by Mher Movsisyan.
• Issue #1625: BZ2File and bz2.decompress() now support multi-stream files. Initial patch by Nir Aides.
• Issue #12175: BufferedReader.read(-1) now calls raw.readall() if available.
• Issue #12175: FileIO.readall() now only reads the file position and size once.
• Issue #12175: RawIOBase.readall() now returns None if read() returns None.
• Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError if the file is closed.
• Issue #11109: New service_action method for BaseServer, used by ForkingMixin class for cleanup. Initial Patch by Justin Warkentin.
• Issue #12045: Avoid duplicate execution of command in ctypes.util._get_soname(). Patch by Sijin Joseph.
• Issue #10818: Remove the Tk GUI and the serve() function of the pydoc module, pydoc -g has been deprecated in Python 3.2 and it has a new enhanced web server.
• Issue #1441530: In imaplib, read the data in one chunk to speed up large reads and simplify code.
• Issue #12070: Fix the Makefile parser of the sysconfig module to handle correctly references to “bogus variable” (e.g. “prefix=$/opt/python”).
• Issue #12100: Don’t reset incremental encoders of CJK codecs at each call to their encode() method anymore, but continue to call the reset() method if the final argument is True.
• Issue #12049: Add RAND_bytes() and RAND_pseudo_bytes() functions to the ssl module.
• Issue #6501: os.device_encoding() returns None on Windows if the application has no console.
• Issue #12105: Add O_CLOEXEC to the os module.
• Issue #12079: Decimal(‘Infinity’).fma(Decimal(‘0’), (3.91224318126786e+19+0j)) now raises TypeError (reflecting the invalid type of the 3rd argument) rather than Decimal.InvalidOperation.
• Issue #12124: zipimport doesn’t keep a reference to zlib.decompress() anymore to be able to unload the module.
• Add the packaging module, an improved fork of distutils (also known as distutils2).
• Issue #12065: connect_ex() on an SSL socket now returns the original errno when the socket’s timeout expires (it used to return None).
• Issue #8809: The SMTP_SSL constructor and SMTP.starttls() now support passing a context argument pointing to an ssl.SSLContext instance. Patch by Kasun Herath.
• Issue #9516: Issue #9516: avoid errors in sysconfig when MACOSX_DEPLOYMENT_TARGET is set in shell.
• Issue #8650: Make zlib module 64-bit clean. compress(), decompress() and their incremental counterparts now raise OverflowError if given an input larger than 4GB, instead of silently truncating the input and returning an incorrect result.
• Issue #12050: zlib.decompressobj().decompress() now clears the unconsumed_tail attribute when called without a max_length argument.
• Issue #12062: Fix a flushing bug when doing a certain type of I/O sequence on a file opened in read+write mode (namely: reading, seeking a bit forward, writing, then seeking before the previous write but still within buffered data, and writing again).
• Issue #9971: Write an optimized implementation of BufferedReader.readinto(). Patch by John O’Connor.
• Issue #11799: urllib.request Authentication Handlers will raise a ValueError when presented with an unsupported Authentication Scheme. Patch contributed by Yuval Greenfield.
• Issue #10419, #6011: build_scripts command of distutils handles correctly non-ASCII path (path to the Python executable). Open and write the script in binary mode, but ensure that the shebang is decodable from UTF-8 and from the encoding of the script.
• Issue #8498: In socket.accept(), allow to specify 0 as a backlog value in order to accept exactly one connection. Patch by Daniel Evers.
• Issue #12011: signal.signal() and signal.siginterrupt() raise an OSError, instead of a RuntimeError: OSError has an errno attribute.
• Issue #3709: add a flush_headers method to BaseHTTPRequestHandler, which manages the sending of headers to output stream and flushing the internal headers buffer. Patch contribution by Andrew Schaaf
• Issue #11743: Rewrite multiprocessing connection classes in pure Python.
• Issue #11164: Stop trying to use _xmlplus in the xml module.
• Issue #11888: Add log2 function to math module. Patch written by Mark Dickinson.
• Issue #12012: ssl.PROTOCOL_SSLv2 becomes optional.
• Issue #8407: The signal handler writes the signal number as a single byte instead of a nul byte into the wakeup file descriptor. So it is possible to wait more than one signal and know which signals were raised.
• Issue #8407: Add pthread_kill(), sigpending() and sigwait() functions to the signal module.
• Issue #11927: SMTP_SSL now uses port 465 by default as documented. Patch by Kasun Herath.
• Issue #12002: ftplib’s abort() method raises TypeError.
• Issue #11916: Add a number of MacOSX specific definitions to the errno module. Patch by Pierre Carrier.
• Issue #11999: fixed sporadic sync failure mailbox.Maildir due to its trying to detect mtime changes by comparing to the system clock instead of to the previous value of the mtime.
• Issue #11072: added MLSD command (RFC-3659) support to ftplib.
• Issue #8808: The IMAP4_SSL constructor now allows passing an SSLContext parameter to control parameters of the secure channel. Patch by Sijin Joseph.
• ntpath.samefile failed to notice that “a.txt” and “A.TXT” refer to the same file on Windows XP. As noticed in issue #10684.
• Issue #12000: When a SSL certificate has a subjectAltName without any dNSName entry, ssl.match_hostname() should use the subject’s commonName. Patch by Nicolas Bareil.
• Issue #10775: assertRaises, assertRaisesRegex, assertWarns, and assertWarnsRegex now accept a keyword argument ‘msg’ when used as context managers. Initial patch by Winston Ewert.
• Issue #10684: shutil.move used to delete a folder on case insensitive filesystems when the source and destination name where the same except for the case.
• Issue #11647: objects created using contextlib.contextmanager now support more than one call to the function when used as a decorator. Initial patch by Ysj Ray.
• Issue #11930: Removed deprecated time.accept2dyear variable. Removed year >= 1000 restriction from datetime.strftime.
• logging: don’t define QueueListener if Python has no thread support.
• functools.cmp_to_key() now works with collections.Hashable().
• Issue #11277: mmap.mmap() calls fcntl(fd, F_FULLFSYNC) on Mac OS X to get around a mmap bug with sparse files. Patch written by Steffen Daode Nurpmeso.
• Issue #8407: Add signal.pthread_sigmask() function to fetch and/or change the signal mask of the calling thread.
• Issue #11858: configparser.ExtendedInterpolation expected lower-case section names.
• Issue #11324: ConfigParser(interpolation=None) now works correctly.
• Issue #11811: ssl.get_server_certificate() is now IPv6-compatible. Patch by Charles-François Natali.
• Issue #11763: don’t use difflib in TestCase.assertMultiLineEqual if the strings are too long.
• Issue #11236: getpass.getpass responds to ctrl-c or ctrl-z on terminal.
• Issue #11856: Speed up parsing of JSON numbers.
• Issue #11005: threading.RLock()._release_save() raises a RuntimeError if the lock was not acquired.
• Issue #11258: Speed up ctypes.util.find_library() under Linux by a factor of 5 to 10. Initial patch by Jonas H.
• Issue #11382: Trivial system calls, such as dup() or pipe(), needn’t release the GIL. Patch by Charles-François Natali.
• Issue #11223: Add threading._info() function providing informations about the thread implementation.
• Issue #11731: simplify/enhance email parser/generator API by introducing policy objects.
• Issue #11768: The signal handler of the signal module only calls Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or parallel calls. PyErr_SetInterrupt() writes also into the wake up file.
• Issue #11492: fix several issues with header folding in the email package.
• Issue #11852: Add missing imports and update tests.
• Issue #11875: collections.OrderedDict’s __reduce__ was temporarily mutating the object instead of just working on a copy.
• Issue #11467: Fix urlparse behavior when handling urls which contains scheme specific part only digits. Patch by Santoso Wijaya.
• collections.Counter().copy() now works correctly for subclasses.
• Issue #11474: Fix the bug with url2pathname() handling of ‘/C|/’ on Windows. Patch by Santoso Wijaya.
• Issue #11684: complete email.parser bytes API by adding BytesHeaderParser.
• The bz2 module now handles 4GiB+ input buffers correctly.
• Issue #9233: Fix json.loads(‘{}’) to return a dict (instead of a list), when _json is not available.
• Issue #11830: Remove unnecessary introspection code in the decimal module.
• Issue #11703: urllib2.geturl() does not return correct url when the original url contains #fragment.
• Issue #10019: Fixed regression in json module where an indent of 0 stopped adding newlines and acted instead like ‘None’.
• Issue #11186: pydoc ignores a module if its name contains a surrogate character in the index of modules.
• Issue #11815: Use a light-weight SimpleQueue for the result queue in concurrent.futures.ProcessPoolExecutor.
• Issue #5162: Treat services like frozen executables to allow child spawning from multiprocessing.forking on Windows.
• logging.basicConfig now supports an optional ‘handlers’ argument taking an iterable of handlers to be added to the root logger. Additional parameter checks were also added to basicConfig.
• Issue #11814: Fix likely typo in multiprocessing.Pool._terminate().
• Issue #11747: Fix range formatting in difflib.context_diff() and difflib.unified_diff().
• Issue #8428: Fix a race condition in multiprocessing.Pool when terminating worker processes: new processes would be spawned while the pool is being shut down. Patch by Charles-François Natali.
• Issue #2650: re.escape() no longer escapes the ‘_’.
• Issue #11757: select.select() now raises ValueError when a negative timeout is passed (previously, a select.error with EINVAL would be raised). Patch by Charles-François Natali.
• Issue #7311: fix html.parser to accept non-ASCII attribute values.
• Issue #11605: email.parser.BytesFeedParser was incorrectly converting multipart subparts with an 8-bit CTE into unicode instead of preserving the bytes.
• Issue #1690608: email.util.formataddr is now RFC 2047 aware: it now has a charset parameter that defaults to utf-8 and is used as the charset for RFC 2047 encoding when the realname contains non-ASCII characters.
• Issue #10963: Ensure that subprocess.communicate() never raises EPIPE.
• Issue #10791: Implement missing method GzipFile.read1(), allowing GzipFile to be wrapped in a TextIOWrapper. Patch by Nadeem Vawda.
• Issue #11707: Added a fast C version of functools.cmp_to_key(). Patch by Filip Gruszczyński.
• Issue #11688: Add sqlite3.Connection.set_trace_callback(). Patch by Torsten Landschoff.
• Issue #11746: Fix SSLContext.load_cert_chain() to accept elliptic curve private keys.
• Issue #5863: Rewrite BZ2File in pure Python, and allow it to accept file-like objects using a new fileobj constructor argument. Patch by Nadeem Vawda.
• unittest.TestCase.assertSameElements has been removed.
• sys.getfilesystemencoding() raises a RuntimeError if initfsencoding() was not called yet: detect bootstrap (startup) issues earlier.
• Issue #11393: Add the new faulthandler module.
• Issue #11618: Fix the timeout logic in threading.Lock.acquire() under Windows.
• Removed the ‘strict’ argument to email.parser.Parser, which has been deprecated since Python 2.4.
• Issue #11256: Fix inspect.getcallargs on functions that take only keyword arguments.
• Issue #11696: Fix ID generation in msilib.
• itertools.accumulate now supports an optional func argument for a user-supplied binary function.
• Issue #11692: Remove unnecessary demo functions in subprocess module.
• Issue #9696: Fix exception incorrectly raised by xdrlib.Packer.pack_int when trying to pack a negative (in-range) integer.
• Issue #11675: multiprocessing.[Raw]Array objects created from an integer size are now zeroed on creation. This matches the behaviour specified by the documentation.
• Issue #7639: Fix short file name generation in bdist_msi
• Issue #11635: Don’t use polling in worker threads and processes launched by concurrent.futures.
• Issue #6811: Allow importlib to change a code object’s co_filename attribute to match the path to where the source code currently is, not where the code object originally came from.
• Issue #8754: Have importlib use the repr of a module name in error messages.
• Issue #11591: Prevent “import site” from modifying sys.path when python was started with -S.
• collections.namedtuple() now adds a _source attribute to the generated class. This make the source more accessible than the outdated “verbose” option which prints to stdout but doesn’t make the source string available.
• Issue #11371: Mark getopt error messages as localizable. Patch by Filip Gruszczyński.
• Issue #11333: Add __slots__ to collections ABCs.
• Issue #11628: cmp_to_key generated class should use __slots__.
• Issue #11666: let help() display named tuple attributes and methods that start with a leading underscore.
• Issue #11662: Make urllib and urllib2 ignore redirections if the scheme is not HTTP, HTTPS or FTP (CVE-2011-1521).
• Issue #5537: Fix time2isoz() and time2netscape() functions of httplib.cookiejar for expiration year greater than 2038 on 32-bit systems.
• Issue #4391: Use proper gettext plural forms in optparse.
• Issue #11127: Raise a TypeError when trying to pickle a socket object.
• Issue #11563: Connection: close header is sent by requests using URLOpener class which helps in closing of sockets after connection is over. Patch contributions by Jeff McNeil and Nadeem Vawda.
• Issue #11459: A bufsize value of 0 in subprocess.Popen() really creates unbuffered pipes, such that select() works properly on them.
• Issue #5421: Fix misleading error message when one of socket.sendto()’s arguments has the wrong type. Patch by Nikita Vetoshkin.
• Issue #10812: Add some extra posix functions to the os module.
• Issue #10979: unittest stdout buffering now works with class and module setup and teardown.
• Issue #11243: fix the parameter querying methods of Message to work if the headers contain un-encoded non-ASCII data.
• Issue #11401: fix handling of headers with no value; this fixes a regression relative to Python2 and the result is now the same as it was in Python2.
• Issue #9298: base64 bodies weren’t being folded to line lengths less than 78, which was a regression relative to Python2. Unlike Python2, the last line of the folded body now ends with a carriage return.
• Issue #11560: shutil.unpack_archive now correctly handles the format parameter. Patch by Evan Dandrea.
• Issue #5870: Add subprocess.DEVNULL constant.
• Issue #11133: fix two cases where inspect.getattr_static can trigger code execution. Patch by Andreas Stührk.
• Issue #11569: use absolute path to the sysctl command in multiprocessing to ensure that it will be found regardless of the shell PATH. This ensures that multiprocessing.cpu_count works on default installs of MacOSX.
• Issue #11501: disutils.archive_utils.make_zipfile no longer fails if zlib is not installed. Instead, the zipfile.ZIP_STORED compression is used to create the ZipFile. Patch by Natalia B. Bidart.
• Issue #11289: smtp.SMTP class is now a context manager so it can be used in a with statement. Contributed by Giampaolo Rodola.
• Issue #11554: Fixed support for Japanese codecs; previously the body output encoding was not done if euc-jp or shift-jis was specified as the charset.
• Issue #11407: TestCase.run returns the result object used or created. Contributed by Janathan Hartley.
• Issue #11500: Fixed a bug in the OS X proxy bypass code for fully qualified IP addresses in the proxy exception list.
• Issue #11491: dbm.error is no longer raised when dbm.open is called with the “n” as the flag argument and the file exists. The behavior matches the documentation and general logic.
• Issue #1162477: Postel Principle adjustment to email date parsing: handle the fact that some non-compliant MUAs use ‘.’ instead of ‘:’ in time specs.
• Issue #11131: Fix sign of zero in decimal.Decimal plus and minus operations when the rounding mode is ROUND_FLOOR.
• Issue #9935: Speed up pickling of instances of user-defined classes.
• Issue #5622: Fix curses.wrapper to raise correct exception if curses initialization fails.
• Issue #11408: In threading.Lock.acquire(), only call gettimeofday() when really necessary. Patch by Charles-François Natali.
• Issue #11391: Writing to a mmap object created with mmap.PROT_READ|mmap.PROT_EXEC would segfault instead of raising a TypeError. Patch by Charles-François Natali.
• Issue #9795: add context manager protocol support for nntplib.NNTP class.
• Issue #11306: mailbox in certain cases adapts to an inability to open certain files in read-write mode. Previously it detected this by checking for EACCES, now it also checks for EROFS.
• Issue #11265: asyncore now correctly handles EPIPE, EBADF and EAGAIN errors on accept(), send() and recv().
• Issue #11377: Deprecate platform.popen() and reimplement it with os.popen().
• Issue #8513: On UNIX, subprocess supports bytes command string.
• Issue #10866: Add socket.sethostname(). Initial patch by Ross Lagerwall.
• Issue #11140: Lock.release() now raises a RuntimeError when attempting to release an unacquired lock, as claimed in the threading documentation. The _thread.error exception is now an alias of RuntimeError. Patch by Filip Gruszczyński. Patch for _dummy_thread by Aymeric Augustin.
• Issue #8594: ftplib now provides a source_address parameter to specify which (address, port) to bind to before connecting.
• Issue #11326: Add the missing connect_ex() implementation for SSL sockets, and make it work for non-blocking connects.
• Issue #11297: Add collections.ChainMap().
• Issue #10755: Add the posix.flistdir() function. Patch by Ross Lagerwall.
• Issue #4761: Add the *at() family of functions (openat(), etc.) to the posix module. Patch by Ross Lagerwall.
• Issue #7322: Trying to read from a socket’s file-like object after a timeout occurred now raises an error instead of silently losing data.
• Issue #11291: poplib.POP no longer suppresses errors on quit().
• Issue #11177: asyncore’s create_socket() arguments can now be omitted.
• Issue #6064: Add a daemon keyword argument to the threading.Thread and multiprocessing.Process constructors in order to override the default behaviour of inheriting the daemonic property from the current thread/process.
• Issue #10956: Buffered I/O classes retry reading or writing after a signal has arrived and the handler returned successfully.
• Issue #10784: New os.getpriority() and os.setpriority() functions.
• Issue #11114: Fix catastrophic performance of tell() on text files (up to 1000x faster in some cases). It is still one to two order of magnitudes slower than binary tell().
• Issue #10882: Add os.sendfile function.
• Issue #10868: Allow usage of the register method of an ABC as a class decorator.
• Issue #11224: Fixed a regression in tarfile that affected the file-like objects returned by TarFile.extractfile() regarding performance, memory consumption and failures with the stream interface.
• Issue #10924: Adding salt and Modular Crypt Format to crypt library. Moved old C wrapper to _crypt, and added a Python wrapper with enhanced salt generation and simpler API for password generation.
• Issue #11074: Make ‘tokenize’ so it can be reloaded.
• Issue #11085: Moved collections abstract base classes into a separate module called collections.abc, following the pattern used by importlib.abc. For backwards compatibility, the names are imported into the collections module.
• Issue #4681: Allow mmap() to work on file sizes and offsets larger than 4GB, even on 32-bit builds. Initial patch by Ross Lagerwall, adapted for 32-bit Windows.
• Issue #11169: compileall module uses repr() to format filenames and paths to escape surrogate characters and show spaces.
• Issue #11089: Fix performance issue limiting the use of ConfigParser() with large config files.
• Issue #10276: Fix the results of zlib.crc32() and zlib.adler32() on buffers larger than 4GB. Patch by Nadeem Vawda.
• Issue #11388: Added a clear() method to MutableSequence
• Issue #11174: Add argparse.MetavarTypeHelpFormatter, which uses type names for the names of optional and positional arguments in help messages.
• Issue #9348: Raise an early error if argparse nargs and metavar don’t match.
• Issue #9026: Fix order of argparse sub-commands in help messages.
• Issue #9347: Fix formatting for tuples in argparse type= error messages.
• Issue #12191: Added shutil.chown() to change user and/or group owner of a given path also specifying their names.
• Issue #13988: The _elementtree accelerator is used whenever available. Now xml.etree.cElementTree becomes a deprecated alias to ElementTree.

Build

• Issue #6807: Run msisupport.mak earlier.
• Issue #10580: Minor grammar change in Windows installer.
• Issue #13326: Clean __pycache__ directories correctly on OpenBSD.
• PEP 393: the configure option –with-wide-unicode is removed.
• Issue #12852: Set _XOPEN_SOURCE to 700, instead of 600, to get POSIX 2008 functions on OpenBSD (e.g. fdopendir).
• Issue #11863: Remove support for legacy systems deprecated in Python 3.2 (following PEP 11). These systems are systems using Mach C Threads, SunOS lightweight processes, GNU pth threads and IRIX threads.
• Issue #8746: Correct faulty configure checks so that os.chflags() and os.lchflags() are once again built on systems that support these functions (BSD and OS X). Also add new stat file flags for OS X (UF_HIDDEN and UF_COMPRESSED).
• Issue #10645: Installing Python no longer creates a Python-X.Y.Z-pyX.Y.egg-info file in the lib-dynload directory.
• Do not accidentally include the directory containing sqlite.h twice when building sqlite3.
• Issue #11217: For 64-bit/32-bit Mac OS X universal framework builds, ensure “make install” creates symlinks in –prefix bin for the “-32” files in the framework bin directory like the installer does.
• Issue #11347: Use –no-as-needed when linking libpython3.so.
• Issue #11411: Fix ‘make DESTDIR=’ with a relative destination.
• Issue #11268: Prevent Mac OS X Installer failure if Documentation package had previously been installed.
• Issue #11495: OSF support is eliminated. It was deprecated in Python 3.2.

IDLE

• Issue #14409: IDLE now properly executes commands in the Shell window when it cannot read the normal config files on startup and has to use the built-in default key bindings. There was previously a bug in one of the defaults.
• IDLE can be launched as python -m idlelib
• Issue #3573: IDLE hangs when passing invalid command line args (directory(ies) instead of file(s)) (Patch by Guilherme Polo)
• Issue #14200: IDLE shell crash on printing non-BMP unicode character.
• Issue #5219: Prevent event handler cascade in IDLE.
• Issue #964437: Make IDLE help window non-modal. Patch by Guilherme Polo and Roger Serwy.
• Issue #13933: IDLE auto-complete did not work with some imported module, like hashlib. (Patch by Roger Serwy)
• Issue #13506: Add ‘’ to path for IDLE Shell when started and restarted with Restart Shell. Original patches by Marco Scataglini and Roger Serwy.
• Issue #4625: If IDLE cannot write to its recent file or breakpoint files, display a message popup and continue rather than crash. Original patch by Roger Serwy.
• Issue #8641: Update IDLE 3 syntax coloring to recognize b”..” and not u”..”. Patch by Tal Einat.
• Issue #13296: Fix IDLE to clear compile __future__ flags on shell restart. (Patch by Roger Serwy)
• Issue #9871: Prevent IDLE 3 crash when given byte stings with invalid hex escape sequences, like b’x0’. (Original patch by Claudiu Popa.)
• Issue #12636: IDLE reads the coding cookie when executing a Python script.
• Issue #12540: Prevent zombie IDLE processes on Windows due to changes in os.kill().
• Issue #12590: IDLE editor window now always displays the first line when opening a long file. With Tk 8.5, the first line was hidden.
• Issue #11088: don’t crash when using F5 to run a script in IDLE on MacOSX with Tk 8.5.
• Issue #1028: Tk returns invalid Unicode null in %A: UnicodeDecodeError. With Tk < 8.5 _tkinter.c:PythonCmd() raised UnicodeDecodeError, caused IDLE to exit. Converted to valid Unicode null in PythonCmd().
• Issue #11718: IDLE’s open module dialog couldn’t find the __init__.py file in a package.

Tools/Demos

• Issue #14053: patchcheck.py (“make patchcheck”) now works with MQ patches. Patch by Francisco Martín Brugué.
• Issue #13930: 2to3 is now able to write its converted output files to another directory tree as well as copying unchanged files and altering the file suffix. See its new -o, -W and –add-suffix options. This makes it more useful in many automated code translation workflows.
• Issue #13628: python-gdb.py is now able to retrieve more frames in the Python traceback if Python is optimized.
• Issue #11996: libpython (gdb), replace “py-bt” command by “py-bt-full” and add a smarter “py-bt” command printing a classic Python traceback.
• Issue #11179: Make ccbench work under Python 3.1 and 2.7 again.
• Issue #10639: reindent.py no longer converts newlines and will raise an error if attempting to convert a file with mixed newlines. “–newline” option added to specify new line character.

Extension Modules

• Issue #16847: Fixed improper use of _PyUnicode_CheckConsistency() in non-pydebug builds. Several extension modules now compile cleanly when assert()s are enabled in standard builds (-DDEBUG flag).
• Issue #13840: The error message produced by ctypes.create_string_buffer when given a Unicode string has been fixed.
• Issue #9975: socket: Fix incorrect use of flowinfo and scope_id. Patch by Vilmos Nebehaj.
• Issue #7777: socket: Add Reliable Datagram Sockets (PF_RDS) support.
• Issue #13159: FileIO and BZ2Compressor/BZ2Decompressor now use a linear-time buffer growth strategy instead of a quadratic-time one.
• Issue #10141: socket: Add SocketCAN (PF_CAN) support. Initial patch by Matthias Fuchs, updated by Tiago Gonçalves.
• Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle would be finalized after the reference to its underlying BufferedRWPair’s writer got cleared by the GC.
• Issue #12881: ctypes: Fix segfault with large structure field names.
• Issue #13058: ossaudiodev: fix a file descriptor leak on error. Patch by Thomas Jarosch.
• Issue #13013: ctypes: Fix a reference leak in PyCArrayType_from_ctype. Thanks to Suman Saha for finding the bug and providing a patch.
• Issue #13022: Fix: _multiprocessing.recvfd() doesn’t check that file descriptor was actually received.
• Issue #1172711: Add ‘long long’ support to the array module. Initial patch by Oren Tirosh and Hirokazu Yamamoto.
• Issue #12483: ctypes: Fix a crash when the destruction of a callback object triggers the garbage collector.
• Issue #12950: Fix passing file descriptors in multiprocessing, under OpenIndiana/Illumos.
• Issue #12764: Fix a crash in ctypes when the name of a Structure field is not a string.
• Issue #11241: subclasses of ctypes.Array can now be subclassed.
• Issue #9651: Fix a crash when ctypes.create_string_buffer(0) was passed to some functions like file.write().
• Issue #10309: Define _GNU_SOURCE so that mremap() gets the proper signature. Without this, architectures where sizeof void* != sizeof int are broken. Patch given by Hallvard B Furuseth.
• Issue #12051: Fix segfault in json.dumps() while encoding highly-nested objects using the C accelerations.
• Issue #12017: Fix segfault in json.loads() while decoding highly-nested objects using the C accelerations.
• Issue #1838: Prevent segfault in ctypes, when _as_parameter_ on a class is set to an instance of the class.

Tests

• Issue #13125: Silence spurious test_lib2to3 output when in non-verbose mode. Patch by Mikhail Novikov.
• Issue #13447: Add a test file to host regression tests for bugs in the scripts found in the Tools directory.
• Issue #10881: Fix test_site failure with OS X framework builds.
• Issue #13901: Prevent test_distutils failures on OS X with –enable-shared.
• Issue #13862: Fix spurious failure in test_zlib due to runtime/compile time minor versions not matching.
• Issue #12804: Fix test_socket and test_urllib2net failures when running tests on a system without internet access.
• Issue #13726: Fix the ambiguous -S flag in regrtest. It is -o/–slow for slow tests.
• Issue #11659: Fix ResourceWarning in test_subprocess introduced by #11459. Patch by Ben Hayden.
• Issue #11577: fix ResourceWarning triggered by improved binhex test coverage
• Issue #11509: Significantly increase test coverage of fileinput. Patch by Denver Coneybeare at PyCon 2011 Sprints.
• Issue #11689: Fix a variable scoping error in an sqlite3 test
• Issue #13786: Remove unimplemented ‘trace’ long option from regrtest.py.
• Issue #13725: Fix regrtest to recognize the documented -d flag. Patch by Erno Tukia.
• Issue #13304: Skip test case if user site-packages disabled (-s or PYTHONNOUSERSITE). (Patch by Carl Meyer)
• Issue #5661: Add a test for ECONNRESET/EPIPE handling to test_asyncore. Patch by Xavier de Gaye.
• Issue #13218: Fix test_ssl failures on Debian/Ubuntu.
• Re-enable lib2to3’s test_parser.py tests, though with an expected failure (see issue 13125).
• Issue #12656: Add tests for IPv6 and Unix sockets to test_asyncore.
• Issue #6484: Add unit tests for mailcap module (patch by Gregory Nofi)
• Issue #11651: Improve the Makefile test targets to run more of the test suite more quickly. The –multiprocess option is now enabled by default, reducing the amount of time needed to run the tests. “make test” and “make quicktest” now include some resource-intensive tests, but no longer run the test suite twice to check for bugs in .pyc generation. Tools/scripts/run_test.py provides an easy platform-independent way to run test suite with sensible defaults.
• Issue #12331: The test suite for the packaging module can now run from an installed Python.
• Issue #12331: The test suite for lib2to3 can now run from an installed Python.
• Issue #12626: In regrtest, allow to filter tests using a glob filter with the -m (or --match) option. This works with all test cases using the unittest module. This is useful with long test suites such as test_io or test_subprocess.
• Issue #12624: It is now possible to fail after the first failure when running in verbose mode (-v or -W), by using the --failfast (or -G) option to regrtest. This is useful with long test suites such as test_io or test_subprocess.
• Issue #12587: Correct faulty test file and reference in test_tokenize. (Patch by Robert Xiao)
• Issue #12573: Add resource checks for dangling Thread and Process objects.
• Issue #12549: Correct test_platform to not fail when OS X returns ‘x86_64’ as the processor type on some Mac systems.
• Skip network tests when getaddrinfo() returns EAI_AGAIN, meaning a temporary failure in name resolution.
• Issue #11812: Solve transient socket failure to connect to ‘localhost’ in test_telnetlib.py.
• Solved a potential deadlock in test_telnetlib.py. Related to issue #11812.
• Avoid failing in test_robotparser when mueblesmoraleda.com is flaky and an overzealous DNS service (e.g. OpenDNS) redirects to a placeholder Web site.
• Avoid failing in test_urllibnet.test_bad_address when some overzealous DNS service (e.g. OpenDNS) resolves a non-existent domain name. The test is now skipped instead.
• Issue #12440: When testing whether some bits in SSLContext.options can be reset, check the version of the OpenSSL headers Python was compiled against, rather than the runtime version of the OpenSSL library.
• Issue #11512: Add a test suite for the cgitb module. Patch by Robbie Clemons.
• Issue #12497: Install test/data to prevent failures of the various codecmaps tests.
• Issue #12496: Install test/capath directory to prevent test_connect_capath testcase failure in test_ssl.
• Issue #12469: Run wakeup and pending signal tests in a subprocess to run the test in a fresh process with only one thread and to not change signal handling of the parent process.
• Issue #8716: Avoid crashes caused by Aqua Tk on OSX when attempting to run test_tk or test_ttk_guionly under a username that is not currently logged in to the console windowserver (as may be the case under buildbot or ssh).
• Issue #12407: Explicitly skip test_capi.EmbeddingTest under Windows.
• Issue #12400: regrtest -W doesn’t rerun the tests twice anymore, but captures the output and displays it on failure instead. regrtest -v doesn’t print the error twice anymore if there is only one error.
• Issue #12141: Install copies of template C module file so that test_build_ext of test_distutils and test_command_build_ext of test_packaging are no longer silently skipped when run outside of a build directory.
• Issue #8746: Add additional tests for os.chflags() and os.lchflags(). Patch by Garrett Cooper.
• Issue #10736: Fix test_ttk test_widgets failures with Cocoa Tk 8.5.9 2.8 + on Mac OS X. (Patch by Ronald Oussoren)
• Issue #12057: Add tests for ISO 2022 codecs (iso2022_jp, iso2022_jp_2, iso2022_kr).
• Issue #12096: Fix a race condition in test_threading.test_waitfor(). Patch written by Charles-François Natali.
• Issue #11614: import __hello__ prints “Hello World!”. Patch written by Andreas Stührk.
• Issue #5723: Improve json tests to be executed with and without accelerations.
• Issue #12041: Make test_wait3 more robust.
• Issue #11873: Change regex in test_compileall to fix occasional failures when when the randomly generated temporary path happened to match the regex.
• Issue #11958: Fix FTP tests for IPv6, bind to ”::1” instead of “localhost”. Patch written by Charles-Francois Natali.
• Issue #8407, #11859: Fix tests of test_io using threads and an alarm: use pthread_sigmask() to ensure that the SIGALRM signal is received by the main thread.
• Issue #11811: Factor out detection of IPv6 support on the current host and make it available as test.support.IPV6_ENABLED. Patch by Charles-François Natali.
• Issue #10914: Add a minimal embedding test to test_capi.
• Issue #11223: Skip test_lock_acquire_interruption() and test_rlock_acquire_interruption() of test_threadsignals if a thread lock is implemented using a POSIX mutex and a POSIX condition variable. A POSIX condition variable cannot be interrupted by a signal (e.g. on Linux, the futex system call is restarted).
• Issue #11790: Fix sporadic failures in test_multiprocessing.WithProcessesTestCondition.
• Fix possible “file already exists” error when running the tests in parallel.
• Issue #11719: Fix message about unexpected test_msilib skip on non-Windows platforms. Patch by Nadeem Vawda.
• Issue #11727: Add a –timeout option to regrtest: if a test takes more than TIMEOUT seconds, dumps the traceback of all threads and exits.
• Issue #11653: fix -W with -j in regrtest.
• The email test suite now lives in the Lib/test/test_email package. The test harness code has also been modernized to allow use of new unittest features.
• regrtest now discovers test packages as well as test modules.
• Issue #11577: improve test coverage of binhex.py. Patch by Arkady Koplyarov.
• New test_crashers added to exercise the scripts in the Lib/test/crashers directory and confirm they fail as expected
• Issue #11578: added test for the timeit module. Patch by Michael Henry.
• Issue #11503: improve test coverage of posixpath.py. Patch by Evan Dandrea.
• Issue #11505: improves test coverage of string.py, increases granularity of string.Formatter tests. Initial patch by Alicia Arlen.
• Issue #11548: Improve test coverage of the shutil module. Patch by Evan Dandrea.
• Issue #11554: Reactivated test_email_codecs.
• Issue #11505: improves test coverage of string.py. Patch by Alicia Arlen
• Issue #11490: test_subprocess.test_leaking_fds_on_error no longer gives a false positive if the last directory in the path is inaccessible.
• Issue #11223: Fix test_threadsignals to fail, not hang, when the non-semaphore implementation of locks is used under POSIX.
• Issue #10911: Add tests on CGI with non-ASCII characters. Patch written by Pierre Quentel.
• Issue #9931: Fix hangs in GUI tests under Windows in certain conditions. Patch by Hirokazu Yamamoto.
• Issue #10512: Properly close sockets under test.test_cgi.
• Issue #10992: Make tests pass under coverage.
• Issue #10826: Prevent sporadic failure in test_subprocess on Solaris due to open door files.
• Issue #10990: Prevent tests from clobbering a set trace function.

C-API

• Issue #13452: PyUnicode_EncodeDecimal() doesn’t support error handlers different than “strict” anymore. The caller was unable to compute the size of the output buffer: it depends on the error handler.
• Issue #13560: Add PyUnicode_DecodeLocale(), PyUnicode_DecodeLocaleAndSize() and PyUnicode_EncodeLocale() functions to the C API to decode/encode from/to the current locale encoding.
• Issue #10831: PyUnicode_FromFormat() supports %li, %lli and %zi formats.
• Issue #11246: Fix PyUnicode_FromFormat(“%V”) to decode the byte string from UTF-8 (with replace error handler) instead of ISO-8859-1 (in strict mode). Patch written by Ray Allen.
• Issue #10830: Fix PyUnicode_FromFormatV(“%c”) for non-BMP characters on narrow build.
• Add PyObject_GenericGetDict and PyObject_GeneriSetDict. They are generic implementations for the getter and setter of a __dict__ descriptor of C types.
• Issue #13727: Add 3 macros to access PyDateTime_Delta members: PyDateTime_DELTA_GET_DAYS, PyDateTime_DELTA_GET_SECONDS, PyDateTime_DELTA_GET_MICROSECONDS.
• Issue #10542: Add 4 macros to work with surrogates: Py_UNICODE_IS_SURROGATE, Py_UNICODE_IS_HIGH_SURROGATE, Py_UNICODE_IS_LOW_SURROGATE, Py_UNICODE_JOIN_SURROGATES.
• Issue #12724: Add Py_RETURN_NOTIMPLEMENTED macro for returning NotImplemented.
• PY_PATCHLEVEL_REVISION has been removed, since it’s meaningless with Mercurial.
• Issue #12173: The first argument of PyImport_ImportModuleLevel is now const char * instead of char *.
• Issue #12380: PyArg_ParseTuple now accepts a bytearray for the ‘c’ format.

Documentation

• Issue #13989: Document that GzipFile does not support text mode, and give a more helpful error message when opened with an invalid mode string.
• Issue #13921: Undocument and clean up sqlite3.OptimizedUnicode, which is obsolete in Python 3.x. It’s now aliased to str for backwards compatibility.
• Issue #12102: Document that buffered files must be flushed before being used with mmap. Patch by Steffen Daode Nurpmeso.
• Issue #8982: Improve the documentation for the argparse Namespace object.
• Issue #9343: Document that argparse parent parsers must be configured before their children.
• Issue #13498: Clarify docs of os.makedirs()’s exist_ok argument. Done with great native-speaker help from R. David Murray.
• Issues #13491 and #13995: Fix many errors in sqlite3 documentation. Initial patch for #13491 by Johannes Vogel.
• Issue #13402: Document absoluteness of sys.executable.
• Issue #13883: PYTHONCASEOK also works on OS X.
• Issue #9021: Add an introduction to the copy module documentation.
• Issue #6005: Examples in the socket library documentation use sendall, where relevant, instead send method.
• Issue #12798: Updated the mimetypes documentation.
• Issue #12949: Document the kwonlyargcount argument for the PyCode_New C API function.
• Issue #13513: Fix io.IOBase documentation to correctly link to the io.IOBase.readline method instead of the readline module.
• Issue #13237: Reorganise subprocess documentation to emphasise convenience functions and the most commonly needed arguments to Popen.
• Issue #13141: Demonstrate recommended style for socketserver examples.
• Issue #11818: Fix tempfile examples for Python 3.

(For information about older versions, consult the HISTORY file.)