Python Developer's Guide

This guide is a comprehensive resource for :ref:`contributing <contributing>` to Python -- for both new and experienced contributors. It is :ref:`maintained <helping-with-the-developers-guide>` by the same community that maintains Python. We welcome your contributions to Python!

Quick Reference

Here are the basic steps needed to get :ref:`set up <setup>` and contribute a patch. This is meant as a checklist, once you know the basics. For complete instructions please see the :ref:`setup guide <setup>`.

Install and set up :ref:`Git <vcsetup>` and other dependencies (see the :ref:`Git Setup <setup>` page for detailed information).
Fork the CPython repository to your GitHub account and :ref:`get the source code <checkout>` using:
```
git clone https://github.com/<your_username>/cpython
cd cpython
```
Build Python, on UNIX and Mac OS use:
```
./configure --with-pydebug && make -j
```
and on Windows use:
```
PCbuild\build.bat -e -d
```
See also :ref:`more detailed instructions <compiling>`, :ref:`how to install and build dependencies <build-dependencies>`, and the platform-specific pages for :ref:`UNIX <unix-compiling>`, :ref:`Mac OS <MacOS>`, and :ref:`Windows <windows-compiling>`.
:doc:`Run the tests <runtests>`:
```
./python -m test -j3
```
On :ref:`most <mac-python.exe>` Mac OS X systems, replace :file:`./python` with :file:`./python.exe`. On Windows, use :file:`python.bat`.
Create a new branch where your work for the issue will go, e.g.:
```
git checkout -b fix-issue-12345 main
```
If an issue does not already exist, please create it. Trivial issues (e.g. typo fixes) do not require any issue to be created.
Once you fixed the issue, run the tests, run make patchcheck, and if everything is ok, commit.
Push the branch on your fork on GitHub and :doc:`create a pull request <pullrequest>`. Include the issue number using gh-NNNN in the pull request description. For example:
```
gh-12345: Fix some bug in spam module
```
Add a News entry into the Misc/NEWS.d directory as individual file. The news entry can be created by using blurb-it, or the blurb tool and its blurb add command. Please read more about blurb in :ref:`documentation <documenting>`.

Note

First time contributors will need to sign the Contributor Licensing Agreement (CLA) as described in the :ref:`Licensing <cla>` section of this guide.

Quick Links

Here are some links that you probably will reference frequently while contributing to Python:

Status of Python branches

Branch	Schedule	Status	First release	End-of-life	Release manager
main	TBA	features	2023-10-03	2028-10	Thomas Wouters
3.11	PEP 664	bugfix	2022-10-03	2027-10	Pablo Galindo Salgado
3.10	PEP 619	bugfix	2021-10-04	2026-10	Pablo Galindo Salgado
3.9	PEP 596	bugfix	2020-10-05	2025-10	Łukasz Langa
3.8	PEP 569	security	2019-10-14	2024-10	Łukasz Langa
3.7	PEP 537	security	2018-06-27	2023-06-27	Ned Deily

Dates in italic are scheduled and can be adjusted.

The main branch is currently the future Python 3.11, and is the only branch that accepts new features. The latest release for each Python version can be found on the download page.

Status:

features:	new features, bugfixes, and security fixes are accepted.
prerelease:	feature fixes, bugfixes, and security fixes are accepted for the upcoming feature release.
bugfix:	bugfixes and security fixes are accepted, new binaries are still released. (Also called maintenance mode or stable release)
security:	only security fixes are accepted and no more binaries are released, but new source-only versions can be released
end-of-life:	release cycle is frozen; no further changes can be pushed to it.

See also the :ref:`devcycle` page for more information about branches.

By default, the end-of-life is scheduled 5 years after the first release, but can be adjusted by the release manager of each branch. All Python 2 versions have reached end-of-life.

Contributing

We encourage everyone to contribute to Python and that's why we have put up this developer's guide. If you still have questions after reviewing the material in this guide, then the Core Python Mentorship group is available to help guide new contributors through the process.

A number of individuals from the Python community have contributed to a series of excellent guides at Open Source Guides.

Core developers and contributors alike will find the following guides useful:

Guide for contributing to Python:

New Contributors	Documentarians	Triagers	Core Developers
:doc:`setup`	:doc:`docquality`	:doc:`tracker`	:doc:`coredev`
:doc:`help`	:doc:`documenting`	:doc:`triaging`	:doc:`developers`
:doc:`pullrequest`	:ref:`style-guide`	:ref:`helptriage`	:doc:`committing`
:doc:`runtests`	:ref:`rst-primer`	:doc:`experts`	:doc:`devcycle`
:doc:`fixingissues`	:ref:`translating`		:doc:`motivations`
:doc:`communication`			:ref:`office hour`
:doc:`gitbootcamp`

Advanced tasks and topics for once you are comfortable:

:doc:`silencewarnings`
Fixing issues found by the :doc:`buildbots <buildbots>`
:doc:`coverity`
Helping out with reviewing open pull requests. See :ref:`how to review a Pull Request <how-to-review-a-pull-request>`.
:doc:`fixingissues`

It is recommended that the above documents be read as needed. New contributors will build understanding of the CPython workflow by reading the sections mentioned in this table. You can stop where you feel comfortable and begin contributing immediately without reading and understanding these documents all at once. If you do choose to skip around within the documentation, be aware that it is written assuming preceding documentation has been read so you may find it necessary to backtrack to fill in missing concepts and terminology.

Proposing changes to Python itself

Improving Python's code, documentation and tests are ongoing tasks that are never going to be "finished", as Python operates as part of an ever-evolving system of technology. An even more challenging ongoing task than these necessary maintenance activities is finding ways to make Python, in the form of the standard library and the language definition, an even better tool in a developer's toolkit.

While these kinds of change are much rarer than those described above, they do happen and that process is also described as part of this guide:

:doc:`stdlibchanges`
:doc:`langchanges`

Other Interpreter Implementations

This guide is specifically for contributing to the Python reference interpreter, also known as CPython (while most of the standard library is written in Python, the interpreter core is written in C and integrates most easily with the C and C++ ecosystems).

There are other Python implementations, each with a different focus. Like CPython, they always have more things they would like to do than they have developers to work on them. Some major examples that may be of interest are:

Key Resources

Coding style guides
- PEP 7 (Style Guide for C Code)
- PEP 8 (Style Guide for Python Code)
Issue tracker
- Meta tracker (issue tracker for the issue tracker)
- :doc:`experts`
Buildbot status
Source code
PEPs (Python Enhancement Proposals)
:doc:`help`
:doc:`developers`

Additional Resources

Anyone can clone the sources for this guide. See :ref:`helping-with-the-developers-guide`.
Help with ...
Tool support
- :doc:`gdb`
- :doc:`clang`
- Various tools with configuration files as found in the Misc directory
- Information about editors and their configurations can be found in the wiki
python.org maintenance
:ref:`Search this guide <search>`

Code of Conduct

Please note that all interactions on Python Software Foundation-supported infrastructure is covered by the PSF Code of Conduct, which includes all infrastructure used in the development of Python itself (e.g. mailing lists, issue trackers, GitHub, etc.). In general this means everyone is expected to be open, considerate, and respectful of others no matter what their position is within the project.

Full Table of Contents

.. toctree::
   :maxdepth: 3

   setup
   help
   pullrequest
   runtests
   coverage
   docquality
   documenting
   silencewarnings
   fixingissues
   tracker
   triaging
   communication
   porting
   coredev
   developers
   committing
   devcycle
   buildbots
   stdlibchanges
   langchanges
   experts
   gdb
   exploring
   grammar
   parser
   compiler
   garbage_collector
   extensions
   c-api
   coverity
   clang
   buildworker
   motivations
   gitbootcamp
   appendix

Uh oh!