Thanks for your interest in our project. Contributions are always welcome!
We are committed to fostering a welcoming, respectful, and harassment-free environment. Be kind!
If you have questions, ideas or want to report a bug, feel free to open an issue. Or go ahead and open a pull request to contribute code. In order to reduce the burden on our maintainers, please make sure that your code follows our style guidelines outlined below.
Use uv to set up a local development environment.
git clone https://github.com/DSD-DBS/py-capellambse
cd py-capellambse
uv sync
uv run pre-commit install
# You may need to explicitly activate the project venv
# to make code completion and tools available:
source .venv/bin/activate.sh # for Linux / Mac
.venv\Scripts\activate # for Windows
You can use uv run <tool>
to avoid having to manually activate the project
venv. For example, to run the unit tests, use:
uv run pytest
The example notebooks (see above) are verified during CI, to ensure their output is up to date. This means they have to be re-run whenever the expected output changes.
Use the following command to start a Jupyter server, which can be used to develop and re-run the example notebooks:
cd docs/source/examples
CAPELLAMBSE_UUID_SEED=0 uv run jupyter lab
Note
The above command provides a static seed for the internal pseudo-random number generator. This is not recommended for production environments. Read more about CAPELLAMBSE_UUID_SEED.
If your browser did not open automatically, follow the instructions in the terminal to start it manually.
We additionally recommend that you set up your editor / IDE as follows.
-
Indent with 4 spaces per level of indentation
-
Maximum line length of 79 (add a ruler / thin line / highlighting / ...)
-
If you use Visual Studio Code: Consider using a platform which supports third-party language servers more easily, and continue with the next point.
Otherwise, set up the editor to run
ruff
andmypy
when saving.Note that the Pylance language server is not recommended, as it occasionally causes false-positive errors for perfectly valid code.
-
If you do not use VSC: Set up your editor to use the python-lsp-server and ruff, which are installed into the development virtualenv by default.
This will provide as-you-type linting as well as automatic formatting on save. Language server clients are available for a wide range of editors, from Vim/Emacs to PyCharm/IDEA.
We use the pre-commit framework to perform some basic code checks at commit time. Before you commit your changes, make sure it is installed and set up, as described in the installation instructions:
uv run pre-commit install
Within the project core group we agreed on using Conventional Commits. Compliance checking is automated via pre-commit.
We base our code style on a modified version of the Google style guide for Python code. The key differences are:
-
Docstrings: The Numpy style guide applies here.
When writing docstrings for functions, use the imperative style, as per PEP-257. For example, write "Do X and Y" instead of "Does X and Y".
-
Overridden methods: If the documentation did not change from the base class (i.e. the base class' method's docstring still applies without modification), do not add a short docstring á la "See base class". This lets automated tools pick up the full base class docstring instead, and is therefore more useful in IDEs etc.
-
Linting: Use ruff for static code analysis, and mypy for static type checking.
-
Formatting: Use ruff as code auto-formatter. The maximum line length is 79, as per PEP-8. This setting should be automatically picked up from the
pyproject.toml
file. The reason for the shorter line length is that it avoids wrapping and overflows in side-by-side split views (e.g. diffs) if there's also information displayed to the side of it (e.g. a tree view of the modified files).Be aware of the different line length of 72 for docstrings. We currently do not have a satisfactory solution to automatically apply or enforce this.
Note that, while you're encouraged to do so in general, it is not a hard requirement to break up long strings into smaller parts. Additionally, never break up strings that are presented to the user in e.g. log messages, as that makes it significantly harder to grep for them.
-
Typing: We do not make an exception for
typing
imports. Instead of writingfrom typing import SomeName
, useimport typing as t
and access typing related classes liket.TypedDict
.Use the new syntax and classes for typing introduced with Python 3.10.
- Instead of
t.Tuple
,t.List
etc. use the builtin classestuple
,list
etc. - For classes that are not builtin (e.g.
Iterable
),import collections.abc as cabc
and then use them likecabc.Iterable
. - Use PEP-604-style unions, e.g.
int | float
instead oft.Union[int, float]
. - Use
... | None
(withNone
always as the last union member) instead oft.Optional[...]
and always explicitly annotate whereNone
is possible.
- Instead of
-
Python style rules: The auto-formatter wins.
-
When working with
dict
s, consider usingt.TypedDict
instead of a more genericdict[str, float|int|str]
-like annotation where possible, as the latter is much less precise (often requiring additionalassert
s orisinstance
checks to pass) and can grow unwieldy very quickly. -
Prefer
t.NamedTuple
overcollections.namedtuple
, because the former uses a more convenientclass ...:
syntax and also supports type annotations.