Welcome! Mypy is a community project that aims to work for a wide range of Python users and Python codebases. If you're trying Mypy on your Python code, your experience and what you can contribute are important to the project's success.
If you haven't already, take a look at the project's README.md file and the Mypy documentation, and try adding type annotations to your file and type-checking it with Mypy.
If you've run into behavior in Mypy you don't understand, or you're having trouble working out a good way to apply it to your code, or you've found a bug or would like a feature it doesn't have, we want to hear from you!
Our main forum for discussion is the project's GitHub issue tracker. This is the right place to start a discussion of any of the above or most any other topic concerning the project.
We have an IRC channel, #python-mypy
on irc.freenode.net. This is
lightly used, but some Mypy core developers are almost always present;
feel free to find us there and we're happy to chat. Substantive
technical discussion will be directed to the issue tracker.
Everyone participating in the Mypy community, and in particular in our issue tracker, pull requests, and IRC channel, is expected to treat other people with respect and more generally to follow the guidelines articulated in the Python Community Code of Conduct.
Even more excellent than a good bug report is a fix for a bug, or the implementation of a much-needed new feature. (*) We'd love to have your contributions.
(*) If your new feature will be a lot of work, we recommend talking to us early -- see below.
We use the usual GitHub pull-request flow, which may be familiar to you if you've contributed to other projects on GitHub. For the mechanics, see our git and GitHub workflow help page, or GitHub's own documentation.
Anyone interested in Mypy may review your code. One of the Mypy core developers will merge your pull request when they think it's ready. For every pull request, we aim to promptly either merge it or say why it's not yet ready; if you go a few days without a reply, please feel free to ping the thread by adding a new comment.
At present the core developers are (alphabetically): David Fisher (@ddfisher) Jukka Lehtosalo (@JukkaL) Greg Price (@gnprice) Guido van Rossum (@gvanrossum)
Before you begin: if your change will be a significant amount of work to write, we highly recommend starting by opening an issue laying out what you want to do. That lets a conversation happen early in case other contributors disagree with what you'd like to do or have ideas that will help you do it.
The best pull requests are focused, clearly describe what they're for and why they're correct, and contain tests for whatever changes they make to the code's behavior. As a bonus these are easiest for someone to review, which helps your pull request get merged quickly! Standard advice about good pull requests for open-source projects applies; we have our own writeup of this advice.
See also our coding conventions -- which consist mainly of a reference to PEP 8 -- for the code you put in the pull request.
You may also find other pages in the Mypy developer guide helpful in developing your change.
We aim to reply to all new issues promptly. We'll assign a milestone to help us track which issues we intend to get to when, and may apply labels to carry some other information. Here's what our milestones and labels mean.
We use GitHub "milestones" (see our list) to roughly order what we want to do soon and less soon.
This means they represent a combination of priority and scale of work. Bugs that aren't a huge deal but do matter to users and don't seem like a lot of work to fix generally go in a near milestone; things that will take longer may go further out.
Specifically: