# Developer Guide Welcome. We are so happy you've decided to contribute. ## Setting up a development environment This guide describes how to install and configure development environments. If you have any problems with the steps here, please reach out in the `dev` channel on [Discord](https://discord.gg/rb6gPXbdAr) or on [Discourse](https://discourse.holoviz.org/). ## TL;DR 0. Open an [issue on Github](https://github.com/holoviz/param/issues) if needed 1. Fork and clone [Param's Github repository](https://github.com/holoviz/param) 2. Install [`pixi`](https://pixi.sh) 3. Run `pixi run setup-dev` to create your development environment 4. Make some changes and run: - `pixi run test-unit` if you updated the source code to run the unit tests - `pixi run test-example` if you updated the notebooks to run them - `pixi run docs-build` if you need to build the website locally 5. Open a Pull Request ## Preliminaries ### Basic understanding of how to contribute to Open Source If this is your first open-source contribution, please study one or more of the below resources. - [How to Get Started with Contributing to Open Source | Video](https://youtu.be/RGd5cOXpCQw) - [Contributing to Open-Source Projects as a New Python Developer | Video](https://youtu.be/jTTf4oLkvaM) - [How to Contribute to an Open Source Python Project | Blog post](https://www.educative.io/blog/contribue-open-source-python-project) ### Git The Param source code is stored in a [Git](https://git-scm.com) source control repository. The first step to working on Param is to install Git onto your system. There are different ways to do this, depending on whether you use Windows, Mac, or Linux. To install Git on any platform, refer to the [Installing Git](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git) section of the [Pro Git Book](https://git-scm.com/book/en/v2). To contribute to Param, you will also need [Github account](https://github.com/join) and knowledge of the [_fork and pull request workflow_](https://docs.github.com/en/get-started/quickstart/contributing-to-projects). ### Pixi Developing all aspects of Param requires a wide range of packages in different environments. To make this more manageable, Pixi manages the developer experience. To install Pixi, follow [this guide](https://pixi.sh/latest/#installation). #### Glossary - Tasks: A task is what can be run with `pixi run `. Tasks can be anything from installing packages to running tests. - Environments: An environment is a set of packages installed in a virtual environment. Each environment has a name; you can run tasks in a specific environment with the `-e` flag. For example, `pixi run -e test-core test-unit` will run the `test-unit` task in the `test-core` environment. - Lock-file: A lock-file is a file that contains all the information about the environments. For more information, see the [Pixi documentation](https://pixi.sh/latest/). :::{admonition} Note :class: info The first time you run `pixi`, it will create a `.pixi` directory in the source directory. This directory will contain all the files needed for the virtual environments. The `.pixi` directory can be large, so it is advised not to put the source directory into a cloud-synced directory. ::: ## Installing the Project ### Cloning the Project The source code for the Param project is hosted on [GitHub](https://github.com/holoviz/param). The first thing you need to do is clone the repository. 1. Go to [github.com/holoviz/param](https://github.com/holoviz/param) 2. [Fork the repository](https://docs.github.com/en/get-started/quickstart/contributing-to-projects#forking-a-repository) 3. Run in your terminal: `git clone https://github.com//param` The instructions for cloning above created a `param` directory at your file system location. This `param` directory is the _source checkout_ for the remainder of this document, and your current working directory is this directory. ### Fetch tags from upstream The version number of the package depends on [`git tags`](https://git-scm.com/book/en/v2/Git-Basics-Tagging), so you need to fetch the tags from the upstream repository: ```bash git remote add upstream https://github.com/holoviz/param.git git fetch --tags upstream git push --tags ``` ## Start developing To start developing, run the following command, this will create an environment called `default` (in `.pixi/envs`), install Param in [editable mode](https://pip.pypa.io/en/stable/topics/local-project-installs/#editable-installs), and install `pre-commit`: ```bash pixi run setup-dev ``` :::{admonition} Note :class: info The first time you run it, it will create a `pixi.lock` file with information for all available environments. This command will take a minute or so to run. ::: All available tasks can be found by running `pixi task list`, the following sections will give a brief introduction to the most common tasks. ### Syncing Git tags with upstream repository If you are working from a forked repository of Param, you will need to sync the tags with the upstream repository. This is needed because the Param version number depends on [`git tags`](https://git-scm.com/book/en/v2/Git-Basics-Tagging). Syncing the git tags can be done with: ```bash pixi run sync-git-tags ``` ## Developer Environment The `default` environment is meant to provide all the tools needed to develop Param. This environment is created by running `pixi run setup-dev`. Run `pixi shell` to activate it; this is equivalent to `source venv/bin/activate` in a Python virtual environment or `conda activate` in a conda environment. If you need to run a command directly instead of via `pixi`, activate the environment and run the command (e.g. `pixi shell` and `pytest param/tests/`). ### VS Code This environment can also be selected in your IDE. In VS Code, this can be done by running the command `Python: Select Interpreter` and choosing `{'default': Pixi}`.

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To confirm you are using this dev environment, check the bottom right corner: ![003](https://assets.holoviews.org/static/dev_guide/003.png) ### Jupyter Lab You can launch Jupyter lab with the `default` environment with `pixi run lab`. This can be advantageous when you need to edit the documentation or debug an example notebook. ## Linting Param uses [`pre-commit`](https://pre-commit.com/) to lint and format the source code. `pre-commit` is installed automatically when running `pixi run setup-dev`; it can also be installed with `pixi run lint-install`. `pre-commit` runs all the linters when a commit is made locally. Linting can be forced to run for all the files with: ```bash pixi run lint ``` :::{admonition} Note :class: info Alternatively, if you have `pre-commit` installed elsewhere you can run: ```bash pre-commit install # To install pre-commit run --all-files # To run on all files ``` ::: ## Testing To help keep Param maintainable, all Pull Requests (PR) with code changes should typically be accompanied by relevant tests. While exceptions may be made for specific circumstances, the default assumption should be that a Pull Request without tests will not be merged. There are three types of tasks and five environments related to tests. ### Unit tests Unit tests are usually small tests executed with [pytest](https://docs.pytest.org). They can be found in `param/tests/`. Unit tests can be run with the `test-unit` task: ```bash pixi run test-unit ``` The task is available in the following environments: 1. `test-310`, `test-311`, `test-312`, `test-313`, and `test-314`. 1. `test-core` Where the first ones have the same environments except for different Python versions. `test-core` only has a core set of dependencies. If you haven't set the environment flag in the command, a menu will help you select which one of the environments to use. ### Example tests Param's documentation consists mainly of Jupyter Notebooks. The example tests execute all the notebooks and fail if an error is raised. Example tests are possible thanks to [nbval](https://nbval.readthedocs.io/) and can be found in the `doc/` folder. Example tests can be run with the following command: ```bash pixi run test-example ``` This task has the same environments as the unit tests except for `test-core`. ## Documentation The documentation can be built with the command: ```bash pixi run docs-build ``` ## Build Param has two build tasks, for building packages for Pip and Conda. ```bash pixi run build-pip pixi run build-conda ``` ## Continuous Integration Every push to the `main` branch or any PR branch on GitHub automatically triggers a test build with [GitHub Actions](https://github.com/features/actions). You can see the list of all current and previous builds at [this URL](https://github.com/holoviz/param/actions) ### Etiquette GitHub Actions provides free build workers for open-source projects. A few considerations will help you be considerate of others needing these limited resources: - Run the tests locally before opening or pushing to an opened PR. - Group commits to meaningful chunks of work before pushing to GitHub (i.e., don't push on every commit).