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<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="color-scheme" content="light dark"> <title>PEP 297 – Support for System Upgrades | peps.python.org</title> <link rel="shortcut icon" href="../_static/py.png"> <link rel="canonical" href="https://peps.python.org/pep-0297/"> <link rel="stylesheet" href="../_static/style.css" type="text/css"> <link rel="stylesheet" href="../_static/mq.css" type="text/css"> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" media="(prefers-color-scheme: light)" id="pyg-light"> <link rel="stylesheet" href="../_static/pygments_dark.css" type="text/css" media="(prefers-color-scheme: dark)" id="pyg-dark"> <link rel="alternate" type="application/rss+xml" title="Latest PEPs" href="https://peps.python.org/peps.rss"> <meta property="og:title" content='PEP 297 – Support for System Upgrades | peps.python.org'> <meta property="og:description" 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onClick="setColourScheme(nextColourScheme())"> <svg aria-hidden="true" class="colour-scheme-icon-when-auto"><use href="#svg-sun-half"></use></svg> <svg aria-hidden="true" class="colour-scheme-icon-when-dark"><use href="#svg-moon"></use></svg> <svg aria-hidden="true" class="colour-scheme-icon-when-light"><use href="#svg-sun"></use></svg> <span class="visually-hidden">Toggle light / dark / auto colour theme</span> </button> </header> <article> <section id="pep-content"> <h1 class="page-title">PEP 297 – Support for System Upgrades</h1> <dl class="rfc2822 field-list simple"> <dt class="field-odd">Author<span class="colon">:</span></dt> <dd class="field-odd">Marc-André Lemburg <mal at lemburg.com></dd> <dt class="field-even">Status<span class="colon">:</span></dt> <dd class="field-even"><abbr title="Formally declined and will not be accepted">Rejected</abbr></dd> <dt class="field-odd">Type<span class="colon">:</span></dt> <dd class="field-odd"><abbr title="Normative PEP with a new feature for Python, implementation change for CPython or interoperability standard for the ecosystem">Standards Track</abbr></dd> <dt class="field-even">Created<span class="colon">:</span></dt> <dd class="field-even">19-Jul-2001</dd> <dt class="field-odd">Python-Version<span class="colon">:</span></dt> <dd class="field-odd">2.6</dd> <dt class="field-even">Post-History<span class="colon">:</span></dt> <dd class="field-even"><p></p></dd> </dl> <hr class="docutils" /> <section id="contents"> <details><summary>Table of Contents</summary><ul class="simple"> <li><a class="reference internal" href="#rejection-notice">Rejection Notice</a></li> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#problem">Problem</a></li> <li><a class="reference internal" href="#proposed-solutions">Proposed Solutions</a></li> <li><a class="reference internal" href="#scope">Scope</a></li> <li><a class="reference internal" href="#credits">Credits</a></li> <li><a class="reference internal" href="#references">References</a></li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> </details></section> <section id="rejection-notice"> <h2><a class="toc-backref" href="#rejection-notice" role="doc-backlink">Rejection Notice</a></h2> <p>This PEP is rejected for failure to generate significant interest.</p> </section> <section id="abstract"> <h2><a class="toc-backref" href="#abstract" role="doc-backlink">Abstract</a></h2> <p>This PEP proposes strategies to allow the Python standard library to be upgraded in parts without having to reinstall the complete distribution or having to wait for a new patch level release.</p> </section> <section id="problem"> <h2><a class="toc-backref" href="#problem" role="doc-backlink">Problem</a></h2> <p>Python currently does not allow overriding modules or packages in the standard library per default. Even though this is possible by defining a <code class="docutils literal notranslate"><span class="pre">PYTHONPATH</span></code> environment variable (the paths defined in this variable are prepended to the Python standard library path), there is no standard way of achieving this without changing the configuration.</p> <p>Since Python’s standard library is starting to host packages which are also available separately, e.g. the distutils, email and PyXML packages, which can also be installed independently of the Python distribution, it is desirable to have an option to upgrade these packages without having to wait for a new patch level release of the Python interpreter to bring along the changes.</p> <p>On some occasions, it may also be desirable to update modules of the standard library without going through the whole Python release cycle, e.g. in order to provide hot-fixes for security problems.</p> </section> <section id="proposed-solutions"> <h2><a class="toc-backref" href="#proposed-solutions" role="doc-backlink">Proposed Solutions</a></h2> <p>This PEP proposes two different but not necessarily conflicting solutions:</p> <ol class="arabic"> <li>Adding a new standard search path to <code class="docutils literal notranslate"><span class="pre">sys.path</span></code>: <code class="docutils literal notranslate"><span class="pre">$stdlibpath/system-packages</span></code> just before the <code class="docutils literal notranslate"><span class="pre">$stdlibpath</span></code> entry. This complements the already existing entry for site add-ons <code class="docutils literal notranslate"><span class="pre">$stdlibpath/site-packages</span></code> which is appended to the <code class="docutils literal notranslate"><span class="pre">sys.path</span></code> at interpreter startup time.<p>To make use of this new standard location, distutils will need to grow support for installing certain packages in <code class="docutils literal notranslate"><span class="pre">$stdlibpath/system-packages</span></code> rather than the standard location for third-party packages <code class="docutils literal notranslate"><span class="pre">$stdlibpath/site-packages</span></code>.</p> </li> <li>Tweaking distutils to install directly into <code class="docutils literal notranslate"><span class="pre">$stdlibpath</span></code> for the system upgrades rather than into <code class="docutils literal notranslate"><span class="pre">$stdlibpath/site-packages</span></code>.</li> </ol> <p>The first solution has a few advantages over the second:</p> <ul class="simple"> <li>upgrades can be easily identified (just look in <code class="docutils literal notranslate"><span class="pre">$stdlibpath/system-packages</span></code>)</li> <li>upgrades can be de-installed without affecting the rest of the interpreter installation</li> <li>modules can be virtually removed from packages; this is due to the way Python imports packages: once it finds the top-level package directory it stay in this directory for all subsequent package submodule imports</li> <li>the approach has an overall much cleaner design than the hackish install on top of an existing installation approach</li> </ul> <p>The only advantages of the second approach are that the Python interpreter does not have to changed and that it works with older Python versions.</p> <p>Both solutions require changes to distutils. These changes can also be implemented by package authors, but it would be better to define a standard way of switching on the proposed behaviour.</p> </section> <section id="scope"> <h2><a class="toc-backref" href="#scope" role="doc-backlink">Scope</a></h2> <p>Solution 1: Python 2.6 and up</p> <p>Solution 2: all Python versions supported by distutils</p> </section> <section id="credits"> <h2><a class="toc-backref" href="#credits" role="doc-backlink">Credits</a></h2> <p>None</p> </section> <section id="references"> <h2><a class="toc-backref" href="#references" role="doc-backlink">References</a></h2> <p>None</p> </section> <section id="copyright"> <h2><a class="toc-backref" href="#copyright" role="doc-backlink">Copyright</a></h2> <p>This document has been placed in the public domain.</p> </section> </section> <hr class="docutils" /> <p>Source: <a class="reference external" href="https://github.com/python/peps/blob/main/peps/pep-0297.rst">https://github.com/python/peps/blob/main/peps/pep-0297.rst</a></p> <p>Last modified: <a class="reference external" href="https://github.com/python/peps/commits/main/peps/pep-0297.rst">2025-02-01 08:55:40 GMT</a></p> </article> <nav id="pep-sidebar"> <h2>Contents</h2> <ul> <li><a class="reference internal" href="#rejection-notice">Rejection Notice</a></li> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#problem">Problem</a></li> <li><a class="reference internal" href="#proposed-solutions">Proposed Solutions</a></li> <li><a class="reference internal" href="#scope">Scope</a></li> <li><a class="reference internal" href="#credits">Credits</a></li> <li><a class="reference internal" href="#references">References</a></li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> <br> <a id="source" href="https://github.com/python/peps/blob/main/peps/pep-0297.rst">Page Source (GitHub)</a> </nav> </section> <script src="../_static/colour_scheme.js"></script> <script src="../_static/wrap_tables.js"></script> <script src="../_static/sticky_banner.js"></script> </body> </html>