(pr_tutorial)=

Pull request step-by-step

The preferred workflow for contributing to PyMC is to fork the GitHub repository, clone it to your local machine, and develop on a feature branch.

Steps

Read the {ref}pr_etiquette.
Fork the project repository by clicking on the 'Fork' button near the top right of the main repository page. This creates a copy of the code under your GitHub user account.

Clone your fork of the PyMC repo from your GitHub account to your local disk, and add the base repository as a remote:

git clone git@github.com:<your GitHub handle>/pymc.git
cd pymc
git remote add upstream git@github.com:pymc-devs/pymc.git

Create a feature branch to hold your development changes:
```
git checkout -b my-feature
```
:::{attention} Always use a feature branch. It's good practice to never routinely work on the main branch of any repository. :::
Project requirements are in requirements.txt, and libraries used for development are in requirements-dev.txt. The easiest (and recommended) way to set up a development environment is via miniconda:

::::{tab-set} :::{tab-item} Linux/MacOS
```
conda env create -f conda-envs/environment-dev.yml
```
::: :::{tab-item} Windows
```
conda env create -f .\conda-envs\windows-environment-dev.yml
```
::: :::{tab-item} Windows (Git Bash)
```
conda env create -f conda-envs/windows-environment-dev.yml
```
::: ::::
```
conda activate pymc-dev
pip install -e .
```
Alternatively you may (probably in a virtual environment) run:
```
pip install -e .
pip install -r requirements-dev.txt
```

Develop the feature on your feature branch.

git checkout my-feature   # no -b flag because the branch is already created

Before committing, run pre-commit checks.

pip install pre-commit
pre-commit run --all      # 👈 to run it manually
pre-commit install        # 👈 to run it automatically before each commit

Add changed files using git add and then git commit files:
```
$ git add modified_files
$ git commit
```
to record your changes locally.
After committing, it is a good idea to sync with the base repository in case there have been any changes:
```
git fetch upstream
git rebase upstream/main
```
Then push the changes to the fork in your GitHub account with:
```
git push -u origin my-feature
```
:::{sidebar} If this is your first contribution, the start of some CI jobs will have to be approved by a maintainer. :::
Go to the GitHub web page of your fork of the PyMC repo. Click the 'Pull request' button to send your changes to the project's maintainers for review. This will send a notification to the committers.

:::{tip} Now that your PR is ready, read the {ref}pr_checklist to make sure it follows best practices. :::