socketserver.py is also questionable On Mon, May 20, 2019 at 11:15 PM Christian Heimes <christ...@python.org> wrote: > > Hi, > > here is the first version of my PEP 594 to deprecate and eventually remove > modules from the standard library. The PEP started last year with talk during > the Python Language Summit 2018, https://lwn.net/Articles/755229/. > > The PEP can be confirmed in two stages. I'm not planning any code changes for > 3.8. Instead I only like to document a bunch of modules as deprecated. Active > deprecation is planned for 3.9 and removal for 3.10. The long deprecation > phase gives us 3 years to change our minds or handle edge cases, too. > > Regards, > Christian > > > ---------------------------------------------------------------------------- > PEP: 594 > Title: Removing dead batteries from the standard library > Author: Christian Heimes <christ...@python.org> > Status: Active > Type: Process > Content-Type: text/x-rst > Created: 20-May-2019 > Post-History: > > > Abstract > ======== > > This PEP proposed a list of standard library modules to be removed from the > standard library. The modules are mostly historic data formats and APIs that > have been superseded a long time ago, e.g. Mac OS 9 and Commodore. > > > Rationale > ========= > > Back in the early days of Python, the interpreter came with a large set of > useful modules. This was often refrained to as "batteries included" > philosophy and was one of the corner stones to Python's success story. > Users didn't have to figure out how to download and install separate > packages in order to write a simple web server or parse email. > > Times have changed. The introduction of the cheese shop (PyPI), setuptools, > and later pip, it became simple and straight forward to download and install > packages. Nowadays Python has a rich and vibrant ecosystem of third party > packages. It's pretty much standard to either install packages from PyPI or > use one of the many Python or Linux distributions. > > On the other hand, Python's standard library is piling up cruft, unnecessary > duplication of functionality, and dispensable features. This is undesirable > for several reasons. > > * Any additional module increases the maintenance cost for the Python core > development team. The team has limited resources, reduced maintenance cost > frees development time for other improvements. > * Modules in the standard library are generally favored and seen as the > de-facto solution for a problem. A majority of users only pick 3rd party > modules to replace a stdlib module, when they have a compelling reason, e.g. > lxml instead of `xml`. The removal of an unmaintained stdlib module > increases the chances of a community contributed module to become widely > used. > * A lean and mean standard library benefits platforms with limited resources > like devices with just a few hundred kilobyte of storage (e.g. BBC > Micro:bit). Python on mobile platforms like BeeWare or WebAssembly > (e.g. pyodide) also benefit from reduced download size. > > The modules in the PEP have been selected for deprecation because their > removal is either least controversial or most beneficial. For example > least controversial are 30 years old multimedia formats like ``sunau`` > audio format, which was used on SPARC and NeXT workstations in the late > 1980ties. The ``crypt`` module has fundamental flaws that are better solved > outside the standard library. > > This PEP also designates some modules as not scheduled for removal. Some > modules have been deprecated for several releases or seem unnecessary at > first glance. However it is beneficial to keep the modules in the standard > library, mostly for environments where installing a package from PyPI is not > an option. This can be cooperate environments or class rooms where external > code is not permitted without legal approval. > > * The usage of FTP is declining, but some files are still provided over > the FTP protocol or hosters offer FTP to upload content. Therefore > ``ftplib`` is going to stay. > * The ``optparse`` and ``getopt`` module are widely used. They are mature > modules with very low maintenance overhead. > * According to David Beazley [5]_ the ``wave`` module is easy to teach to > kids and can make crazy sounds. Making a computer generate crazy sounds is > powerful and highly motivating exercise for a 9yo aspiring developer. It's > a fun battery to keep. > > > Deprecation schedule > ==================== > > 3.8 > --- > > This PEP targets Python 3.8. Version 3.8.0 final is scheduled to be released > a few months before Python 2.7 will reach its end of lifetime. We expect that > Python 3.8 will be targeted by users that migrate to Python 3 in 2019 and > 2020. To reduce churn and to allow a smooth transition from Python 2, > Python 3.8 will neither raise `DeprecationWarning` nor remove any > modules that have been scheduled for removal. Instead deprecated modules will > just be *documented* as deprecated. Optionally modules may emit a > `PendingDeprecationWarning`. > > All deprecated modules will also undergo a feature freeze. No additional > features should be added. Bug should still be fixed. > > 3.9 > --- > > Starting with Python 3.9, deprecated modules will start issuing > `DeprecationWarning`. > > > 3.10 > ---- > > In 3.10 all deprecated modules will be removed from the CPython repository > together with tests, documentation, and autoconf rules. > > > PEP acceptance process > ====================== > > 3.8.0b1 is scheduled to be release shortly after the PEP is officially > submitted. Since it's improbable that the PEP will pass all stages of the > PEP process in time, I propose a two step acceptance process that is > analogous Python's two release deprecation process. > > The first *provisionally accepted* phase targets Python 3.8.0b1. In the first > phase no code is changes or removed. Modules are only documented as > deprecated. > > The final decision, which modules will be removed and how the removed code > is preserved, can be delayed for another year. > > > Deprecated modules > ================== > > The modules are grouped as data encoding, multimedia, network, OS interface, > and misc modules. The majority of modules are for old data formats or > old APIs. Some others are rarely useful and have better replacements on > PyPI, e.g. Pillow for image processing or NumPy-based projects to deal with > audio processing. > > .. csv-table:: Table 1: Proposed modules deprecations > :header: "Module", "Deprecated in", "To be removed", "Replacement" > > aifc,3.8,3.10,\- > asynchat,3.8,3.10,asyncio > asyncore,3.8,3.10,asyncio > audioop,3.8,3.10,\- > binhex,3.8,3.10,\- > cgi,3.8,3.10,\- > cgitb,3.8,3.10,\- > chunk,3.8,3.10,\- > colorsys,**3.8?**,**3.10?**,\- > crypt,3.8,3.10,\- > fileinput,3.8,3.10,argparse > formatter,3.4,3.10,\- > fpectl,**3.7**,**3.7**,\- > getopt,**3.2**,**keep**,"argparse, optparse" > imghdr,3.8,3.10,\- > imp,**3.4**,3.10,importlib > lib2to3,\-,**keep**, > macpath,**3.7**,**3.8**,\- > msilib,3.8,3.10,\- > nntplib,3.8,3.10,\- > nis,3.8,3.10,\- > optparse,\-,**keep**,argparse > ossaudiodev,3.8,3.10,\- > pipes,3.8,3.10,subprocess > smtpd,**3.7**,3.10,aiosmtpd > sndhdr,3.8,3.10,\- > spwd,3.8,3.10,\- > sunau,3.8,3.10,\- > uu,3.8,3.10,\- > wave,\-,**keep**, > xdrlib,3.8,3.10,\- > > > Data encoding modules > --------------------- > > binhex > ~~~~~~ > > The `binhex <https://docs.python.org/3/library/binhex.html>`_ module encodes > and decodes Apple Macintosh binhex4 data. It was originally developed for > TSR-80. In the 1980s and early 1990s it was used on classic Mac OS 9 to > encode binary email attachments. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > uu > ~~ > > The `uu <https://docs.python.org/3/library/uu.html>`_ module provides > uuencode format, an old binary encoding format for email from 1980. The uu > format has been replaced by MIME. The uu codec is provided by the binascii > module. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > xdrlib > ~~~~~~ > > The `xdrlib <https://docs.python.org/3/library/xdrlib.html>`_ module supports > the Sun External Data Representation Standard. XDR is an old binary > serialization format from 1987. These days it's rarely used outside > specialized domains like NFS. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > > Multimedia modules > ------------------ > > aifc > ~~~~ > > The `aifc <https://docs.python.org/3/library/aifc.html>`_ module provides > support for reading and writing AIFF and AIFF-C files. The Audio Interchange > File Format is an old audio format from 1988 based on Amiga IFF. It was most > commonly used on the Apple Macintosh. These days only few specialized > application use AIFF. > > Module type > pure Python (depends on `audioop`_ C extension) > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > audioop > ~~~~~~~ > > The `audioop <https://docs.python.org/3/library/audioop.html>`_ module > contains helper functions to manipulate raw audio data and adaptive > differential pulse-code modulated audio data. The module is implemented in > C without any additional dependencies. The `aifc`_, `sunau`_, and `wave`_ > module depend on `audioop`_ for some operations. > > Module type > C extension > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > colorsys > ~~~~~~~~ > > The `colorsys <https://docs.python.org/3/library/colorsys.html>`_ module > defines color conversion functions between RGB, YIQ, HSL, and HSV coordinate > systems. The Pillow library provides much faster conversation between > color systems. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > `Pillow <https://pypi.org/project/Pillow/>`_, > `colorspacious <https://pypi.org/project/colorspacious/>`_ > > chunk > ~~~~~ > > The `chunk <https://docs.python.org/3/library/chunk.html>`_ module provides > support for reading and writing Electronic Arts' Interchange File Format. > IFF is an old audio file format originally introduced for Commodore and > Amiga. The format is no longer relevant. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > imghdr > ~~~~~~ > > The `imghdr <https://docs.python.org/3/library/imghdr.html>`_ module is a > simple tool to guess the image file format from the first 32 bytes > of a file or buffer. It supports only a limited amount of formats and > neither returns resolution nor color depth. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > *n/a* > > ossaudiodev > ~~~~~~~~~~~ > > The `ossaudiodev <https://docs.python.org/3/library/ossaudiodev.html>`_ > module provides support for Open Sound System, an interface to sound > playback and capture devices. OSS was initially free software, but later > support for newer sound devices and improvements were proprietary. Linux > community abandoned OSS in favor of ALSA [1]_. Some operation systems like > OpenBSD and NetBSD provide an incomplete [2]_ emulation of OSS. > > Module type > C extension > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > sndhdr > ~~~~~~ > > The `sndhdr <https://docs.python.org/3/library/sndhdr.html>`_ module is > similar to the `imghdr`_ module but for audio formats. It guesses file > format, channels, frame rate, and sample widths from the first 512 bytes of > a file or buffer. The module only supports AU, AIFF, HCOM, VOC, WAV, and > other ancient formats. > > Module type > pure Python (depends on `audioop`_ C extension for some operations) > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > *n/a* > > sunau > ~~~~~ > > The `sunau <https://docs.python.org/3/library/sunhdr.html>`_ module provides > support for Sun AU sound format. It's yet another old, obsolete file format. > > Module type > pure Python (depends on `audioop`_ C extension for some operations) > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > > Networking modules > ------------------ > > asynchat > ~~~~~~~~ > > The `asynchat <https://docs.python.org/3/library/asynchat.html>`_ module > is build on top of `asyncore`_ and has been deprecated since Python 3.6. > > Module type > pure Python > Deprecated in > 3.6 > Removed in > 3.10 > Substitute > asyncio > > asyncore > ~~~~~~~~ > > The `asyncore <https://docs.python.org/3/library/asyncore.html>`_ module was > the first module for asynchronous socket service clients and servers. It > has been replaced by asyncio and is deprecated since Python 3.6. > > The ``asyncore`` module is also used in stdlib tests. The tests for > ``ftplib``, ``logging``, ``smptd``, ``smtplib``, and ``ssl`` are partly > based on ``asyncore``. These tests must be updated to use asyncio or > threading. > > Module type > pure Python > Deprecated in > 3.6 > Removed in > 3.10 > Substitute > asyncio > > > cgi > ~~~ > > The `cgi <https://docs.python.org/3/library/cgi.html>`_ module is a support > module for Common Gateway Interface (CGI) scripts. CGI is deemed as > inefficient because every incoming request is handled in a new process. PEP > 206 considers the module as *designed poorly and are now near-impossible > to fix*. > > Several people proposed to either keep the cgi module for features like > `cgi.parse_qs()` or move `cgi.escape()` to a different module. The > functions `cgi.parse_qs` and `cgi.parse_qsl` have been > deprecated for a while and are actually aliases for > `urllib.parse.parse_qs` and `urllib.parse.parse_qsl`. The > function `cgi.quote` has been deprecated in favor of `html.quote` > with secure default values. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > > cgitb > ~~~~~ > > The `cgitb <https://docs.python.org/3/library/cgitb.html>`_ module is a > helper for the cgi module for configurable tracebacks. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > smtpd > ~~~~~ > > The `smtpd <https://docs.python.org/3/library/smtpd.html>`_ module provides > a simple implementation of a SMTP mail server. The module documentation > recommends ``aiosmtpd``. > > Module type > pure Python > Deprecated in > **3.7** > To be removed in > 3.10 > Substitute > aiosmtpd > > nntplib > ~~~~~~~ > > The `nntplib <https://docs.python.org/3/library/nntplib.html>`_ module > implements the client side of the Network News Transfer Protocol (nntp). News > groups used to be a dominant platform for online discussions. Over the last > two decades, news has been slowly but steadily replaced with mailing lists > and web-based discussion platforms. > > The ``nntplib`` tests have been the cause of additional work in the recent > past. Python only contains client side of NNTP. The test cases depend on > external news server. These servers were unstable in the past. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > > Operating system interface > -------------------------- > > crypt > ~~~~~ > > The `crypt <https://docs.python.org/3/library/crypt.html>`_ module implements > password hashing based on ``crypt(3)`` function from ``libcrypt`` or > ``libxcrypt`` on Unix-like platform. The algorithms are mostly old, of poor > quality and insecure. Users are discouraged to use them. > > * The module is not available on Windows. Cross-platform application need > an alternative implementation any way. > * Only DES encryption is guarenteed to be available. DES has an extremely > limited key space of 2**56. > * MD5, salted SHA256, salted SHA512, and Blowfish are optional extension. > SSHA256 and SSHA512 are glibc extensions. Blowfish (bcrypt) is the only > algorithm that is still secure. However it's in glibc and therefore not > commonly available on Linux. > * Depending on the platform, the ``crypt`` module is not thread safe. Only > implementations with ``crypt_r(3)`` are thread safe. > > Module type > C extension + Python module > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > `bcrypt <https://pypi.org/project/bcrypt/>`_, > `passlib <https://pypi.org/project/passlib/>`_, > `argon2cffi <https://pypi.org/project/argon2-cffi/>`_, > hashlib module (PBKDF2, scrypt) > > macpath > ~~~~~~~ > > The `macpath <https://docs.python.org/3/library/macpath.html>`_ module > provides Mac OS 9 implementation of os.path routines. Mac OS 9 is no longer > supported > > Module type > pure Python > Deprecated in > 3.7 > Removed in > 3.8 > Substitute > **none** > > nis > ~~~ > > The `nis <https://docs.python.org/3/library/nis.html>`_ module provides > NIS/YP support. Network Information Service / Yellow Pages is an old and > deprecated directory service protocol developed by Sun Microsystems. It's > designed successor NIS+ from 1992 never took off. For a long time, libc's > Name Service Switch, LDAP, and Kerberos/GSSAPI are considered a more powerful > and more secure replacement of NIS. > > Module type > C extension > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > spwd > ~~~~ > > The `spwd <https://docs.python.org/3/library/spwd.html>`_ module provides > direct access to Unix shadow password database using non-standard APIs. > In general it's a bad idea to use the spwd. The spwd circumvents system > security policies, it does not use the PAM stack, and is > only compatible with local user accounts. > > Module type > C extension > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > Misc modules > ------------ > > fileinput > ~~~~~~~~~ > > The `fileinput <https://docs.python.org/3/library/fileinput.html>`_ module > implements a helpers to iterate over a list of files from ``sys.argv``. The > module predates the optparser and argparser module. The same functionality > can be implemented with the argparser module. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > argparse > > formatter > ~~~~~~~~~ > > The `formatter <https://docs.python.org/3/library/formatter.html>`_ module > is an old text formatting module which has been deprecated since Python 3.4. > > Module type > pure Python > Deprecated in > 3.4 > To be removed in > 3.10 > Substitute > *n/a* > > imp > ~~~ > > The `imp <https://docs.python.org/3/library/imp.html>`_ module is the > predecessor of the > `importlib <https://docs.python.org/3/library/importlib.html>`_ module. Most > functions have been deprecated since Python 3.3 and the module since > Python 3.4. > > Module type > C extension > Deprecated in > 3.4 > To be removed in > 3.10 > Substitute > importlib > > msilib > ~~~~~~ > > The `msilib <https://docs.python.org/3/library/msilib.html>`_ package is a > Windows-only package. It supports the creation of Microsoft Installers (MSI). > The package also exposes additional APIs to create cabinet files (CAB). The > module is used to facilitate distutils to create MSI installers with > ``bdist_msi`` command. In the past it was used to create CPython's official > Windows installer, too. > > Microsoft is slowly moving away from MSI in favor of Windows 10 Apps (AppX) > as new deployment model [3]_. > > Module type > C extension + Python code > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > **none** > > pipes > ~~~~~ > > The `pipes <https://docs.python.org/3/library/pipes.html>`_ module provides > helpers to pipe the input of one command into the output of another command. > The module is built on top of ``os.popen``. Users are encouraged to use > the subprocess module instead. > > Module type > pure Python > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > subprocess module > > Removed modules > =============== > > fpectl > ------ > > The `fpectl <https://docs.python.org/3.6/library/fpectl.html>`_ module was > never built by default, its usage was discouraged and considered dangerous. > It also required a configure flag that caused an ABI incompatibility. The > module was removed in 3.7 by Nathaniel J. Smith in > `bpo-29137 <https://bugs.python.org/issue29137>`_. > > Module type > C extension + CAPI > Deprecated in > 3.7 > Removed in > 3.7 > Substitute > **none** > > > Modules to keep > =============== > > Some modules were originally proposed for deprecation. > > lib2to3 > ------- > > The `lib2to3 <https://docs.python.org/3/library/2to3.html>`_ package provides > the ``2to3`` command to transpile Python 2 code to Python 3 code. > > The package is useful for other tasks besides porting code from Python 2 to > 3. For example `black`_ uses it for code reformatting. > > Module type > pure Python > > getopt > ------ > > The `getopt <https://docs.python.org/3/library/getopt.html>`_ module mimics > C's getopt() option parser. Although users are encouraged to use argparse > instead, the getopt module is still widely used. > > Module type > pure Python > > optparse > -------- > > The `optparse <https://docs.python.org/3/library/optparse.html>`_ module is > the predecessor of the argparse module. Although it has been deprecated for > many years, it's still widely used. > > Module type > pure Python > Deprecated in > 3.2 > Substitute > argparse > > wave > ~~~~ > > The `wave <https://docs.python.org/3/library/wave.html>`_ module provides > support for the WAV sound format. The module uses one simple function > from the `audioop`_ module to perform byte swapping between little and big > endian formats. Before 24 bit WAV support was added, byte swap used to be > implemented with the ``array`` module. To remove ``wave``'s dependency on the > ``audioop``, the byte swap function could be either be moved to another > module (e.g. ``operator``) or the ``array`` module could gain support for > 24 bit (3 byte) arrays. > > Module type > pure Python (depends on *byteswap* from `audioop`_ C extension) > Deprecated in > 3.8 > To be removed in > 3.10 > Substitute > *n/a* > > > Future maintenance of removed modules > ===================================== > > The main goal of the PEP is to reduce the burden and workload on the Python > core developer team. Therefore removed modules will not be maintained by > the core team as separate PyPI packages. However the removed code, tests and > documentation may be moved into a new git repository, so community members > have a place from which they can pick up and fork code. > > A first draft of a `legacylib <https://github.com/tiran/legacylib>`_ > repository is available on my private Github account. > > It's my hope that some of the deprecated modules will be picked up and > adopted by users that actually care about them. For example ``colorsys`` and > ``imghdr`` are useful modules, but have limited feature set. A fork of > ``imghdr`` can add new features and support for more image formats, without > being constrained by Python's release cycle. > > Most of the modules are in pure Python and can be easily packaged. Some > depend on a simple C module, e.g. `audioop`_ and `crypt`_. Since `audioop`_ > does not depend on any external libraries, it can be shipped in as binary > wheels with some effort. Other C modules can be replaced with ctypes or cffi. > For example I created `legacycrypt <https://github.com/tiran/legacycrypt>`_ > with ``_crypt`` extension reimplemented with a few lines of ctypes code. > > > Discussions > =========== > > * Elana Hashman and Nick Coghlan suggested to keep the *getopt* module. > * Berker Peksag proposed to deprecate and removed *msilib*. > * Brett Cannon recommended to delay active deprecation warnings and removal > of modules like *imp* until Python 3.10. Version 3.8 will be released > shortly before Python 2 reaches end of lifetime. A delay reduced churn for > users that migrate from Python 2 to 3.8. > * Brett also came up with the idea to keep lib2to3. The package is useful > for other purposes, e.g. `black <https://pypi.org/project/black/>`_ uses > it to reformat Python code. > * At one point, distutils was mentioned in the same sentence as this PEP. > To avoid lengthy discussion and delay of the PEP, I decided against dealing > with distutils. Deprecation of the distutils package will be handled by > another PEP. > * Multiple people (Gregory P. Smith, David Beazley, Nick Coghlan, ...) > convinced me to keep the `wave`_ module. [4]_ > * Gregory P. Smith proposed to deprecate `nntplib`_. [4]_ > > > References > ========== > > .. [1] https://en.wikipedia.org/wiki/Open_Sound_System#Free,_proprietary,_free > .. [2] https://man.openbsd.org/ossaudio > .. [3] > https://blogs.msmvps.com/installsite/blog/2015/05/03/the-future-of-windows-installer-msi-in-the-light-of-windows-10-and-the-universal-windows-platform/ > .. [4] https://twitter.com/ChristianHeimes/status/1130257799475335169 > .. [5] https://twitter.com/dabeaz/status/1130278844479545351 > > > Copyright > ========= > > This document has been placed in the public domain. > > > > .. > Local Variables: > mode: indented-text > indent-tabs-mode: nil > sentence-end-double-space: t > fill-column: 70 > coding: utf-8 > End: > > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > https://mail.python.org/mailman/options/python-dev/andrew.svetlov%40gmail.com
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