micropython-lib follows the same general conventions as the main MicroPython repository. Please see micropython/CONTRIBUTING.md and micropython/CODECONVENTIONS.md.
Please include enough information for someone to reproduce the issue you are describing. This will typically include:
- The version of MicroPython you are using (e.g. the firmware filename, git hash, or version info printed by the startup message).
- What board/device you are running MicroPython on.
- Which package you have installed, how you installed it, and what version.
When installed via
mip
, all packages will have a__version__
attribute. - A simple code snippet that demonstrates the issue.
If you have a how-to question or are looking for help with using MicroPython or packages from micropython-lib, please post at the discussion forum instead.
The same rules for commit messages, signing-off commits, and commit structure apply as for the main MicroPython repository.
All Python code is formatted using the black
tool. You can run tools/codeformat.py
to apply
black
automatically before submitting a PR. The GitHub CI will also run the
ruff tool to apply further "linting"
checks.
Similar to the main repository, a configuration is provided for the
pre-commit tool to apply black
code formatting
rules and run ruff
automatically. See the documentation for using pre-commit
in the code conventions document
In addition to the conventions from the main repository, there are some specific conventions and guidelines for micropython-lib:
-
The first line of the commit message should start with the name of the package, followed by a short description of the commit. Package names are globally unique in the micropython-lib directory structure.
For example:
shutil: Add disk_usage function.
-
Although we encourage keeping the code short and minimal, please still use comments in your code. Typically, packages will be installed via
mip
and so they will be compiled to bytecode where comments will not contribute to the installed size. -
All packages must include a
manifest.py
, including ametadata()
line with at least a description and a version. -
Prefer to break larger packages up into smaller chunks, so that just the required functionality can be installed. The way to do this is to have a base package, e.g.
mypackage
containingmypackage/__init__.py
, and then an "extension" package, e.g.mypackage-ext
containing additional files e.g.mypackage/ext.py
. Seecollections-defaultdict
as an example. -
If you think a package might be extended in this way in the future, prefer to create a package directory with
package/__init__.py
, rather than a singlemodule.py
. -
Packages in the python-stdlib directory should be CPython compatible and implement a subset of the CPython equivalent. Avoid adding MicroPython-specific extensions. Please include a link to the corresponding CPython docs in the PR.
-
Include tests (ideally using the
unittest
package) astest_*.py
. Otherwise, provide examples asexample_*.py
. When porting CPython packages, prefer to use the existing tests rather than writing new ones from scratch. -
When porting an existing third-party package, please ensure that the source license is compatible.
-
To make it easier for others to install packages directly from your PR before it is merged, consider opting-in to automatic package publishing (see Publishing packages from forks). If you do this, consider quoting the commands to install packages in your Pull Request description.
You can easily publish the packages from your micropython-lib fork by opting in to a system based on GitHub Actions and GitHub Pages:
- Open your fork's repository in the GitHub web interface.
- Navigate to "Settings" -> "Secrets and variables" -> "Actions" -> "Variables".
- Click "New repository variable"
- Create a variable named
MICROPY_PUBLISH_MIP_INDEX
with valuetrue
(or any "truthy" value). - The settings for GitHub Actions and GitHub Pages features should not need to be changed from the repository defaults, unless you've explicitly disabled them.
The next time you push commits to a branch in your fork, GitHub Actions will run an additional step in the "Build All Packages" workflow named "Publish Packages for branch".
Anyone can then install these packages as described under Installing packages from forks. The exact commands are also quoted in the GitHub Actions log for the "Publish Packages for branch" step.
To opt-out again, delete the MICROPY_PUBLISH_MIP_INDEX
variable and
(optionally) delete the gh-pages
branch from your fork.
Note: While enabled, all micropython-lib packages will be published each time
a change is pushed to any branch in your fork. A commit is added to the
gh-pages
branch each time. In a busy repository, the gh-pages
branch may
become quite large. The actual .git
directory size on disk should still be
quite small, as most of the content will be duplicated. If you're worried that
the gh-pages
branch has become too large then you can always delete this
branch from GitHub. GitHub Actions will create a new gh-pages
branch the next
time you push a change.