Python Developer’s Guide#
This guide is a comprehensive resource for contributing to Python – for both new and experienced contributors. It is maintained by the same community that maintains Python. We welcome your contributions to Python!
Here are the basic steps needed to get set up and contribute a patch. This is meant as a checklist, once you know the basics. For complete instructions please see the setup guide.
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
./python -m test -j3
On most Mac OS X systems, replace
./python.exe. On Windows, use
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 create a pull request. Include the issue number using
gh-NNNNin the pull request description. For example:
gh-12345: Fix some bug in spam module
Add a News entry into the
Misc/NEWS.ddirectory as individual file. The news entry can be created by using blurb-it, or the blurb tool and its
blurb addcommand. Please read more about
First time contributors will need to sign the Contributor Licensing Agreement (CLA) as described in the Licensing section of this guide.
Status of Python branches#
Pablo Galindo Salgado
Pablo Galindo Salgado
Dates in italic are scheduled and can be adjusted.
The main branch is currently the future Python 3.12, and is the only branch that accepts new features. The latest release for each Python version can be found on the download page.
new features, bugfixes, and security fixes are accepted.
feature fixes, bugfixes, and security fixes are accepted for the upcoming feature release.
bugfixes and security fixes are accepted, new binaries are still released. (Also called maintenance mode or stable release)
only security fixes are accepted and no more binaries are released, but new source-only versions can be released
release cycle is frozen; no further changes can be pushed to it.
See also the Development Cycle 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.
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:
Advanced tasks and topics for once you are comfortable:
Fixing issues found by the buildbots
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:
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:
PyPy: A Python interpreter focused on high speed (JIT-compiled) operation on major platforms
Jython: A Python interpreter focused on good integration with the Java Virtual Machine (JVM) environment
IronPython: A Python interpreter focused on good integration with the Common Language Runtime (CLR) provided by .NET and Mono
Stackless: A Python interpreter focused on providing lightweight microthreads while remaining largely compatible with CPython specific extension modules
PEPs (Python Enhancement Proposals)
Anyone can clone the sources for this guide. See Helping with the Developer’s Guide.
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#
- Getting Started
- Where to Get Help
- Lifecycle of a Pull Request
- Quick Guide
- Step-by-step Guide
- Making Good PRs
- Making Good Commits
- Converting an Existing Patch from b.p.o to GitHub
- Leaving a Pull Request Review on GitHub
- Dismissing Review from Another Core Developer
- Running & Writing Tests
- Increase Test Coverage
- Helping with Documentation
- Documenting Python
- Style guide
- reStructuredText Primer
- Additional Markup Constructs
- Building the documentation
- Silence Warnings From the Test Suite
- Fixing “easy” Issues (and Beyond)
- Issue Tracking
- Using the Issue Tracker
- Disagreement With a Resolution on the Issue Tracker
- Helping Triage Issues
- Gaining the “Triager” Role on the Issue Tracker
- Sub-pages related to the Issue Tracker
- Triaging an Issue
- Following Python’s Development
- Standards of behaviour in these communication channels
- Mailing Lists
- Discourse (discuss.python.org web forum)
- Discord (private chat server)
- Setting Expectations for Open Source Participation
- Additional Repositories
- Porting Python to a new platform
- How to Become a Core Developer
- Developer Log
- Accepting Pull Requests
- Development Cycle
- Repository Administration
- Continuous Integration
- Adding to the Stdlib
- Changing the Python Language
- Experts Index
- gdb Support
- Exploring CPython’s Internals
- Changing CPython’s Grammar
- Guide to CPython’s Parser
- How PEG Parsers Work
- Debugging generated parsers
- Design of CPython’s Compiler
- Design of CPython’s Garbage Collector
- Updating standard library extension modules
- Changing Python’s C API
- Coverity Scan
- Dynamic Analysis with Clang
- Running a buildbot worker
- Core Developer Motivations and Affiliations
- Git Bootcamp and Cheat Sheet
- Forking CPython GitHub Repository
- Cloning a Forked CPython Repository
- Listing the Remote Repositories
- Setting Up Your Name and Email Address
- Creating and Switching Branches
- Deleting Branches
- Renaming Branch
- Staging and Committing Files
- Reverting Changes
- Stashing Changes
- Comparing Changes
- Pushing Changes
- Creating a Pull Request
- Updating your CPython Fork
- Applying a Patch to Git
- Downloading Other’s Patches
- Accepting and Merging a Pull Request
- Backporting Merged Changes
- Editing a Pull Request Prior to Merging
- Appendix: Topics