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peps/pep-0011.txt
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| PEP: 11 | |
| Title: CPython platform support | |
| Author: Martin von Löwis <martin@v.loewis.de>, | |
| Brett Cannon <brett@python.org> | |
| Status: Active | |
| Type: Process | |
| Content-Type: text/x-rst | |
| Created: 07-Jul-2002 | |
| Post-History: `18-Aug-2007 <https://mail.python.org/archives/list/python-dev@python.org/thread/DSSGXU5LBCMKYMZBRVB6RF3YAB6ST5AV/>`__, | |
| `14-May-2014 <https://mail.python.org/archives/list/python-dev@python.org/thread/T7WTUJ6TD3IGYGWV3M4PHJWNLM2WPZAW/>`__, | |
| `20-Feb-2015 <https://mail.python.org/archives/list/python-dev@python.org/thread/OEQHRR2COYZDL6LZ42RBZOMIUB32WI34/#L3K7IKGVT4ND45SKAJPJ3Q2ADVK5KP52>`__, | |
| `10-Mar-2022 <https://mail.python.org/archives/list/python-committers@python.org/thread/K757345KX6W5ZLTWYBUXOXQTJJTL7GW5/>`__, | |
| Abstract | |
| ======== | |
| This PEP documents how an operating system (platform) becomes | |
| supported in CPython, what platforms are currently supported, and | |
| documents past support. | |
| Rationale | |
| ========= | |
| Over time, the CPython source code has collected various pieces of | |
| platform-specific code, which, at some point in time, was | |
| considered necessary to use CPython on a specific platform. | |
| Without access to this platform, it is not possible to determine | |
| whether this code is still needed. As a result, this code may | |
| either break during CPython's evolution, or it may become | |
| unnecessary as the platforms evolve as well. | |
| Allowing these fragments to grow poses the risk of | |
| unmaintainability: without having experts for a large number of | |
| platforms, it is not possible to determine whether a certain | |
| change to the CPython source code will work on all supported | |
| platforms. | |
| To reduce this risk, this PEP specifies what is required for a | |
| platform to be considered supported by CPython as well as providing a | |
| procedure to remove code for platforms with few or no CPython | |
| users. | |
| This PEP also lists what plaforms *are* supported by the CPython | |
| interpreter. This lets people know what platforms are directly | |
| supported by the CPython development team. | |
| Support tiers | |
| ============= | |
| Platform support is broken down into *tiers*. Each tier comes with | |
| different requirements which lead to different promises being made | |
| about support. | |
| To be promoted to a tier, steering council support is required and is | |
| expected to be driven by team consensus. Demotion to a lower tier | |
| occurs when the requirements of the current tier are no longer met for | |
| a platform for an extended period of time based on the judgment of | |
| the release manager or steering council. For platforms which no longer | |
| meet the requirements of any tier by b1 of a new feature release, an | |
| announcement will be made to warn the community of the pending removal | |
| of support for the platform (e.g. in the b1 announcement). If the | |
| platform is not brought into line for at least one of the tiers by the | |
| first release candidate, it will be listed as unsupported in this PEP. | |
| Tier 1 | |
| ------ | |
| - `STATUS <https://github.com/python/cpython/actions/workflows/build.yml?query=branch%3Amain+is%3Acompleted>`__ | |
| - CI failures block releases. | |
| - Changes which would break the ``main`` branch are not allowed to be merged; | |
| any breakage should be fixed or reverted immediately. | |
| - All core developers are responsible to keep ``main``, and thus these | |
| platforms, working. | |
| - Failures on these platforms **block a release**. | |
| ======================== ===== | |
| Target Triple Notes | |
| ======================== ===== | |
| i686-pc-windows-msvc | |
| x86_64-pc-windows-msvc | |
| x86_64-apple-darwin BSD libc, clang | |
| x86_64-unknown-linux-gnu glibc, gcc | |
| ======================== ===== | |
| Tier 2 | |
| ------ | |
| - `STATUS <https://buildbot.python.org/all/#/builders?tags=%2B3.x&tags=%2Btier-2>`__ | |
| - Must have a reliable buildbot. | |
| - At least **two** core developers are signed up to support the platform. | |
| - Changes which break any of these platforms are to be **fixed or | |
| reverted within 24 hours**. | |
| - Failures on these platforms **block a release**. | |
| ============================= ========================== ======== | |
| Target Triple Notes Contacts | |
| ============================= ========================== ======== | |
| aarch64-apple-darwin clang Ned Deily, Ronald Oussoren, Dong-hee Na | |
| aarch64-unknown-linux-gnu glibc, gcc Petr Viktorin, Victor Stinner | |
| glibc, clang Victor Stinner, Gregory P. Smith | |
| powerpc64le-unknown-linux-gnu glibc, gcc Petr Viktorin, Victor Stinner | |
| x86_64-unknown-linux-gnu glibc, clang Victor Stinner, Gregory P. Smith | |
| ============================= ========================== ======== | |
| Tier 3 | |
| ------ | |
| - `STATUS <https://buildbot.python.org/all/#/builders?tags=%2B3.x&tags=%2Btier-3>`__ | |
| - Must have a reliable buildbot. | |
| - At least **one** core developer is signed up to support the platform. | |
| - No response SLA to failures. | |
| - Failures on these platforms do **not** block a release. | |
| ================================ =========================== ======== | |
| Target Triple Notes Contacts | |
| ================================ =========================== ======== | |
| aarch64-pc-windows-msvc Steve Dower | |
| armv7l-unknown-linux-gnueabihf Raspberry Pi OS, glibc, gcc Gregory P. Smith | |
| powerpc64le-unknown-linux-gnu glibc, clang Victor Stinner | |
| s390x-unknown-linux-gnu glibc, gcc Victor Stinner | |
| wasm32-unknown-emscripten Christian Heimes, Brett Cannon | |
| wasm32-unknown-wasi Christian Heimes, Brett Cannon | |
| x86_64-unknown-freebsd BSD libc, clang Victor Stinner | |
| ================================ =========================== ======== | |
| All other platforms | |
| ------------------- | |
| Support for a platform may be partial within the code base, such as | |
| from active development around platform support or accidentally. | |
| Code changes to platforms not listed in the above tiers may be rejected | |
| or removed from the code base without a deprecation process if they | |
| cause a maintenance burden or obstruct general improvements. | |
| Platforms not listed here may be supported by the wider Python | |
| community in some way. If your desired platform is not listed above, | |
| please perform a search online to see if someone is already providing | |
| support in some form. | |
| Notes | |
| ----- | |
| Microsoft Windows | |
| ''''''''''''''''' | |
| Windows versions prior to Windows 10 follow Microsoft's `Fixed Lifecycle Policy | |
| <https://learn.microsoft.com/en-us/lifecycle/policies/fixed>`__, | |
| with a mainstream support phase for 5 years after release, | |
| where the product is generally commercially available, | |
| and an additional 5 year extended support phase, | |
| where paid support is still available and certain bug fixes are released. | |
| `Extended Security Updates (ESU) | |
| <https://learn.microsoft.com/en-us/lifecycle/faq/extended-security-updates>`_ | |
| is a paid program available to high-volume enterprise customers | |
| as a "last resort" option to receive certain security updates after extended support ends. | |
| ESU is considered a distinct phase that follows the expiration of extended support. | |
| Windows 10 and later follow Microsoft's `Modern Lifecycle Policy | |
| <https://learn.microsoft.com/en-us/lifecycle/policies/modern>`__, | |
| which varies per-product, per-version, per-edition and per-channel. | |
| Generally, feature updates (1709, 22H2) occur every 6-12 months | |
| and are supported for 18-36 months; | |
| Server and IoT editions, and LTSC channel releases are supported for 5-10 years, | |
| and the latest feature release of a major version (Windows 10, Windows 11) | |
| generally receives new updates for at least 10 years following release. | |
| Microsoft's `Windows Lifecycle FAQ | |
| <https://learn.microsoft.com/en-us/lifecycle/faq/windows>`_ | |
| has more specific and up-to-date guidance. | |
| CPython's Windows support currently follows Microsoft's lifecycles. | |
| A new feature release X.Y.0 will support all Windows versions | |
| whose *extended support* phase has not yet expired. | |
| Subsequent bug fix releases will support the same Windows versions | |
| as the original feature release, even if no longer supported by Microsoft. | |
| New versions of Windows released while CPython is in maintenance mode | |
| may be supported at the discretion of the core team and release manager. | |
| Each feature release is built by a specific version of Microsoft | |
| Visual Studio. That version should have mainstream support when the | |
| release is made. Developers of extension modules will generally need | |
| to use the same Visual Studio release; they are concerned both with | |
| the availability of the versions they need to use, and with keeping | |
| the zoo of versions small. The CPython source tree will keep | |
| unmaintained build files for older Visual Studio releases, for which | |
| patches will be accepted. Such build files will be removed from the | |
| source tree 3 years after the extended support for the compiler has | |
| ended (but continue to remain available in revision control). | |
| Legacy C Locale | |
| ''''''''''''''' | |
| Starting with CPython 3.7.0, \*nix platforms are expected to provide | |
| at least one of ``C.UTF-8`` (full locale), ``C.utf8`` (full locale) or | |
| ``UTF-8`` (``LC_CTYPE``-only locale) as an alternative to the legacy ``C`` | |
| locale. | |
| Any Unicode-related integration problems that occur only in the legacy ``C`` | |
| locale and cannot be reproduced in an appropriately configured non-ASCII | |
| locale will be closed as "won't fix". | |
| Unsupporting platforms | |
| ====================== | |
| If a platform drops out of tiered support, a note must be posted | |
| in this PEP that the platform is no longer actively supported. This | |
| note must include: | |
| - the name of the system | |
| - the first release number that does not support this platform | |
| anymore, and | |
| - the first release where the historical support code is actively | |
| removed | |
| In some cases, it is not possible to identify the specific list of | |
| systems for which some code is used (e.g. when autoconf tests for | |
| absence of some feature which is considered present on all | |
| supported systems). In this case, the name will give the precise | |
| condition (usually a preprocessor symbol) that will become | |
| unsupported. | |
| At the same time, the CPython source code must be changed to | |
| produce a build-time error if somebody tries to install CPython on | |
| this platform. On platforms using autoconf, configure must fail. | |
| This gives potential users of the platform a chance to step | |
| forward and offer maintenance. | |
| No-longer-supported platforms | |
| ============================= | |
| * | Name: MS-DOS, MS-Windows 3.x | |
| | Unsupported in: Python 2.0 | |
| | Code removed in: Python 2.1 | |
| * | Name: SunOS 4 | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: DYNIX | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: dgux | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Minix | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Irix 4 and --with-sgi-dl | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Linux 1 | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Systems defining __d6_pthread_create (configure.in) | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Systems defining PY_PTHREAD_D4, PY_PTHREAD_D6, | |
| or PY_PTHREAD_D7 in thread_pthread.h | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Systems using --with-dl-dld | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: Systems using --without-universal-newlines, | |
| | Unsupported in: Python 2.3 | |
| | Code removed in: Python 2.4 | |
| * | Name: MacOS 9 | |
| | Unsupported in: Python 2.4 | |
| | Code removed in: Python 2.4 | |
| * | Name: Systems using --with-wctype-functions | |
| | Unsupported in: Python 2.6 | |
| | Code removed in: Python 2.6 | |
| * | Name: Win9x, WinME, NT4 | |
| | Unsupported in: Python 2.6 (warning in 2.5 installer) | |
| | Code removed in: Python 2.6 | |
| * | Name: AtheOS | |
| | Unsupported in: Python 2.6 (with "AtheOS" changed to "Syllable") | |
| | Build broken in: Python 2.7 (edit configure to re-enable) | |
| | Code removed in: Python 3.0 | |
| | Details: http://www.syllable.org/discussion.php?id=2320 | |
| * | Name: BeOS | |
| | Unsupported in: Python 2.6 (warning in configure) | |
| | Build broken in: Python 2.7 (edit configure to re-enable) | |
| | Code removed in: Python 3.0 | |
| * | Name: Systems using Mach C Threads | |
| | Unsupported in: Python 3.2 | |
| | Code removed in: Python 3.3 | |
| * | Name: SunOS lightweight processes (LWP) | |
| | Unsupported in: Python 3.2 | |
| | Code removed in: Python 3.3 | |
| * | Name: Systems using --with-pth (GNU pth threads) | |
| | Unsupported in: Python 3.2 | |
| | Code removed in: Python 3.3 | |
| * | Name: Systems using Irix threads | |
| | Unsupported in: Python 3.2 | |
| | Code removed in: Python 3.3 | |
| * | Name: OSF* systems (issue 8606) | |
| | Unsupported in: Python 3.2 | |
| | Code removed in: Python 3.3 | |
| * | Name: OS/2 (issue 16135) | |
| | Unsupported in: Python 3.3 | |
| | Code removed in: Python 3.4 | |
| * | Name: VMS (issue 16136) | |
| | Unsupported in: Python 3.3 | |
| | Code removed in: Python 3.4 | |
| * | Name: Windows 2000 | |
| | Unsupported in: Python 3.3 | |
| | Code removed in: Python 3.4 | |
| * | Name: Windows systems where COMSPEC points to command.com | |
| | Unsupported in: Python 3.3 | |
| | Code removed in: Python 3.4 | |
| * | Name: RISC OS | |
| | Unsupported in: Python 3.0 (some code actually removed) | |
| | Code removed in: Python 3.4 | |
| * | Name: IRIX | |
| | Unsupported in: Python 3.7 | |
| | Code removed in: Python 3.7 | |
| * | Name: Systems without multithreading support | |
| | Unsupported in: Python 3.7 | |
| | Code removed in: Python 3.7 | |
| Discussions | |
| =========== | |
| * April 2022: `Consider adding a Tier 3 to tiered platform support | |
| <https://mail.python.org/archives/list/python-committers@python.org/thread/V3OZPJGA5VJFYM6XYGPZIVPOIYKX6KTD/>`_ | |
| (Victor Stinner) | |
| * March 2022: `Proposed tiered platform support | |
| <https://mail.python.org/archives/list/python-committers@python.org/thread/K757345KX6W5ZLTWYBUXOXQTJJTL7GW5/>`_ | |
| (Brett Cannon) | |
| * February 2015: `Update to PEP 11 to clarify garnering platform support | |
| <https://mail.python.org/archives/list/python-dev@python.org/thread/OEQHRR2COYZDL6LZ42RBZOMIUB32WI34/>`_ | |
| (Brett Cannon) | |
| * May 2014: `Where is our official policy of what platforms we do support? | |
| <https://mail.python.org/archives/list/python-dev@python.org/thread/T7WTUJ6TD3IGYGWV3M4PHJWNLM2WPZAW/>`_ | |
| (Brett Cannon) | |
| * August 2007: `PEP 11 update - Call for port maintainers to step forward | |
| <https://mail.python.org/archives/list/python-dev@python.org/thread/DSSGXU5LBCMKYMZBRVB6RF3YAB6ST5AV/>`_ | |
| (Skip Montanaro) | |
| Copyright | |
| ========= | |
| This document is placed in the public domain or under the | |
| CC0-1.0-Universal license, whichever is more permissive. |