First of all, thanks for taking the time to contribute to Textual!
You can contribute to Textual in many ways:
- Report a bug
- Add a new feature
- Fix a bug
- Improve the documentation
To make a code or documentation contribution you will need to set up Textual locally. You can follow these steps:
- Make sure you have Poetry installed (see instructions here)
- Clone the Textual repository
- Run
poetry shell
to create a virtual environment for the dependencies - Run
poetry install
to install all dependencies - Make sure the latest version of Textual was installed by running the command
textual --version
- Install the pre-commit hooks with the command
pre-commit install
Once you have Textual installed, run the Textual demo to get an impression of what Textual can do and to double check that everything was installed correctly:
python -m textual
-
Read any issue instructions carefully. Feel free to ask for clarification if any details are missing.
-
Add docstrings to all of your code (functions, methods, classes, ...). The codebase should have enough examples for you to copy from.
-
Write tests for your code.
- If you are fixing a bug, make sure to add regression tests that link to the original issue.
- If you are implementing a visual element, make sure to add snapshot tests. See below for more details.
Before you open your PR, please go through this checklist and make sure you've checked all the items that apply:
- Update the
CHANGELOG.md
- Format your code with black (
make format
) - All your code has docstrings in the style of the rest of the codebase
- Your code passes all tests (
make test
)
(Read this if the command make
doesn't work for you.)
If you change the documentation, you will want to build the documentation to make sure everything looks like it should.
The command make docs-serve-offline
should start a server that will let you preview the documentation locally and that should reload whenever you save changes to the documentation or the code files.
(Read this if the command make
doesn't work for you.)
When you open a PR, your code will be reviewed by one of the Textual maintainers. In that review process,
- We will take a look at all of the changes you are making
- We might ask for clarifications (why did you do X or Y?)
- We might ask for more tests/more documentation
- We might ask for some code changes
The sole purpose of those interactions is to make sure that, in the long run, everyone has the best experience possible with Textual and with the feature you are implementing/fixing.
Don't be discouraged if a reviewer asks for code changes. If you go through our history of pull requests, you will see that every single one of the maintainers has had to make changes following a review.
Snapshot tests ensure that visual things (like widgets) look like they are supposed to.
PR #1969 is a good example of what adding snapshot tests looks like: it amounts to a change in the file tests/snapshot_tests/test_snapshots.py
that should run an app that you write and compare it against a historic snapshot of what that app should look like.
When you create a new snapshot test, run it with pytest -vv tests/snapshot_tests/test_snapshots.py
.
Because you just created this snapshot test, there is no history to compare against and the test will fail.
After running the snapshot tests, you should see a link that opens an interface in your browser.
This interface should show all failing snapshot tests and a side-by-side diff between what the app looked like when the test ran versus the historic snapshot.
Make sure your snapshot app looks like it is supposed to and that you didn't break any other snapshot tests.
If everything looks fine, you can run make test-snapshot-update
to update the snapshot history with your new snapshot.
This will write to the file tests/snapshot_tests/__snapshots__/test_snapshots.ambr
, which you should NOT modify by hand.
(Read this if the command make
doesn't work for you.)
Seems a little overwhelming? Join our community on Discord to get help!
Textual has a Makefile
file that contains the most common commands used when developing Textual.
(Read about Make and makefiles on Wikipedia.)
If you don't have Make and you're on Windows, you may want to install Make.