This guide assumes you have forked and checked-out the repository. It is recommended that you install Hydra in a virtual environment like conda or virtualenv.
Install Miniconda and create an empty Conda environment with:
conda create -n hydra38 python=3.8 -y
Activate the environment:
conda activate hydra38
From the source tree, install Hydra in development mode with the following command:
pip install -e ".[dev]" -e .
Hydra is using a test automation tool called nox to manage tests, linting, code coverage etc.
nox will run all the configured sessions. You can see the full list of nox sessions with
nox -l and run specific sessions
nox -s NAME (you may need to quote the session name in some cases)
The code need to pass verification by the following tools:
black .: Automatic code formatting for Python
flake8: PEP8 compliance checker for Python, this includes copyright header verification
isort .: Ensure imports are sorted properly
mypy --strict .: Ensures code passes strict type checking
The easiest way to run all the required verifications is with
nox -s lint.
It is also recommended that you install pre-commit hooks (use
pre-commit install), this will ensure that those tests
are ran just before you commit your code.
Any pull request that does not pass the linting will fail the automated testing.
pytest at the repository root to run all the Hydra core tests.
To run the tests of individual plugins, use
nox -l. a few examples:
nox -s test_corewill test Hydra core on all supported Python versions
nox -s "test_core-3.6(pip install)": Test on Python 3.6 with
pip installas installation method
nox -s "test_plugins-3.8(pip install -e)": Test plugins on Python 3.8 with
pip install -eas installation method
NEWS.md file is managed using
towncrier and all non trivial changes
must be accompanied by a news entry.
To add an entry to the news file, first you need to have created an issue describing the change you want to make. A Pull Request itself may function as such, but it is preferred to have a dedicated issue (for example, in case the PR ends up rejected due to code quality reasons).
Once you have an issue or pull request, you take the number and you create a
file inside of the
news/ directory named after that issue number with one of the following extensions:
removal: Removal or deprecation of a feature
feature: New feature
bugfix: Bug fix
plugin: New plugin, or an update to an existing plugin
config: Changes or addition to the configuration structure of Hydra
docs: Major addition or updates to documentation
If your issue or PR number is
1234 and this change is fixing a bug, then you would
create a file
news/1234.bugfix. PRs can span multiple categories by creating
multiple files (for instance, if you added a feature and deprecated/removed the
old feature at the same time, you would create
news/NNNN.removal). Likewise if a PR touches multiple issues/PRs you may
create a file for each of them with the exact same contents and Towncrier will
The contents of this file is markdown formatted text that will be used as the content of the news file entry. You do not need to reference the issue or PR numbers here as towncrier will automatically add a reference to all of the affected issues when rendering the news file.
In order to maintain a consistent style in the
NEWS.md file, it is
preferred to keep the news entry to the point, in sentence case, shorter than
80 characters and in an imperative tone -- an entry should complete the sentence
"This change will ...". In rare cases, where one line is not enough, use a
summary line in an imperative tone followed by a blank line separating it
from a description of the feature/change in one or more paragraphs, each wrapped
at 80 characters. Remember that a news entry is meant for end users and should
only contain details relevant to an end user.