CONTRIBUTING.md

SQLFluff - Contributing

🌟 First - thanks for being interested in improving SQLFluff! 😃

🌟 Second - please read and familiarise yourself with both the content of this guide and also our code of conduct.

🌟 Third - the best way to get started contributing, is to use the tool in anger and then to submit bugs and features through GitHub. In particular, in helping to develop the parser, examples of queries that do not parse as expected are especially helpful.

🌟 Fourth - making sure that our documentation is up-to-date and useful for new users is really important. If you are a new user, you are in precisely the best position to do this. Familiarise yourself with the tool (as per step 2 above) and familiarise yourself with the current documentation (live version at docs.sqlfluff.com and the source can be found in the docs folder of the repo). Pull requests are always welcome with documentation improvements. Keep in mind that there are linting checks in place for good formatting so keep an eye on the tests whenever submitting a PR. We also have a GitHub wiki for longer tutorials. We welcome contributions, suggestions or requests for the wiki.

🌟 Fifth - if you are so inclined - pull requests on the core codebase are always welcome. Dialect additions are often a good entry point for new contributors, and we have a wiki page to help you through your first contribution. Bear in mind that all the tests should pass, and test coverage should not decrease unduly as part of the changes which you make. You may find it useful to familiarise yourself with the architectural principles here and with the current documentation here.

How The Community Works

SQLFluff is maintained by a community of volunteers, which means we have a few processes in place to allow everyone to contribute at a level that suits them and at a time that suits them. These are not meant to be a way of restricting development, but a way of allowing the community to agree what to focus on and then effectively direct its focus toward that. Anyone can pipe up in these discussions, and the more we hear from users the more we can build a tool that is useful for the community.

• Large features for consideration will be organised into Major Releases. These will usually include significant changes in functionality or backwards-incompatible changes. As some of these features may require significant coordination, discussion or development work, there is a process for each major release to work out what features will fit into that release.
  • Each major release will have its own GitHub issue. For example, the link to the issue for 0.6.0 is here.
  • Features or issues are organised into a shortlist. During the initial discussion for the release, each feature is vetted for enough clarity that someone in the community can pick it up. Issues, where we cannot reach clarity, will be pushed to the next release. Getting this clarity is important before development work progresses so that we know that larger changes are a) in line with the aims of the project and b) are effectively pre-approved changes so that there are not any surprises when it comes to merging.
  • Once we reach the deadline for closing the roadmap for a release the focus on development work should be on those features.
• Small features and bug fixes (assuming no backward compatibility issues) do not need to go through the same process and vetting and can be picked up and merged at any time.

Maintainers

A small group of people volunteer their time to maintain the project and share the responsibility for responding to issues and reviewing any proposed changes via pull requests. Each one of them will be trying to follow the process above and keep development work on the project moving. That means for smaller changes and improvements they may review changes as individuals and merge them into the project in a very lightweight way. For larger changes, especially if not already part of the current major release process the expectation is that they will involve other members or the maintainer community or the project admins before merging in larger changes or giving the green light to major structural project changes.

Nerdy Details

Developing and Running SQLFluff Locally

Requirements

The simplest way to set up a development environment is to use tox. First ensure that you have tox installed:

python3.8 -m pip install -U tox

IMPORTANT: tox must be installed with a minimum of Python 3.8 as the mypy checks are incompatible with 3.7. Those using newer versions of Python may replace python3.8 as necessary (the test suite runs primarily under 3.12 for example).

Note: Unfortunately tox does not currently support setting just a minimum Python version (though this may be be coming in tox 4!).

Creating a virtual environment

A virtual environment can then be created and activated by running (check the requirements before running this):

tox -e dbt021-py38 --devenv .venv
source .venv/bin/activate

(The dbt021-py38 environment is a good default choice. However any version can be installed by replacing dbt021-py38 with py, py37, py39, dbt020-py38, etc. py defaults to the python version that was used to install tox. However, to be able to run all tests including the dbt templater, choose one of the dbt environments.)

Windows users should call .venv\Scripts\activate rather than source .venv/bin/activate.

This virtual environment will already have the package installed in editable mode for you, as well as requirements_dev.txt and plugins/sqlfluff-plugin-example. Additionally if a dbt virtual environment was specified, you will also have dbt-core, dbt-postgres, and plugins/sqlfluff-templater-dbt available.

Wiki

We have a GitHub wiki with some more long form tutorials for contributors, particularly those new to SQLFluff or contributing to open source. We welcome contributions, suggestions or requests for the wiki.

Developing plugins

If you're working on plugins (like the dbt templater), you'll also need to install those plugins too in an editable mode. This works the same way as the main project but you'll need to do each one explicitly. e.g.

pip install -e plugins/sqlfluff-templater-dbt/.

NOTE: For packages intended to be installed like this, the source code must be directly within a subdirectory with the name of the package and not in a subdirectory such as src. This is due to a restriction in the implementation of setup.py in editable mode.

Testing

To test locally, SQLFluff uses tox (check the requirements!). The test suite can be run via:

tox

This will build and test for several Python versions, and also lint the project. Practically on a day-to-day basis, you might only want to lint and test for one Python version, so you can always specify a particular environment. For example, if you are developing in Python 3.8 you might call...

tox -e generate-fixture-yml,py38,linting,mypy

...or if you also want to see the coverage reporting...

tox -e generate-fixture-yml,cov-init,py38,cov-report,linting,mypy

NB: The cov-init task clears the previous test results, the py38 environment generates the results for tests in that Python version and the cov-report environment reports those results out to you (excluding dbt).

tox accepts posargs to allow you to refine your test run, which is much faster while working on an issue, before running full tests at the end. For example, you can run specific tests by making use of the -k option in pytest:

tox -e py38 -- -k AL02 test

Alternatively, you can also run tests from a specific directory or file only:

tox -e py38 -- test/cli
tox -e py38 -- test/cli/commands_test.py

You can also manually test your updated code against a SQL file via:

sqlfluff parse test.sql

(ensure your virtual environment is activated first).

How to use and understand the test suite

When developing for SQLFluff, you may not need (or wish) to run the whole test suite, depending on what you are working on. Here are a couple of scenarios for development, and which parts of the test suite you may find most useful.

1. For dialect improvements (i.e. changes to anything in src/sqlfluff/dialects) you should not need to continuously run the full core test suite. Running either tox -e generate-fixture-yml (if using tox), or setting up a python virtualenv and running test/generate_parse_fixture_yml.py directly will usually be sufficient. Both of these options accept arguments to restrict runs to specific dialects to further improve iteration speed. e.g.
   • tox -e generate-fixture-yml -- -d mysql will run just the mysql tests.
   • python test/generate_parse_fixture_yml.py -d mysql will do the same.
2. Developing for the dbt templater should only require running the dbt test suite (see below).
3. Developing rules and rule plugins there are a couple of scenarios.
   • When developing a new rule or working with a more isolated rule, you should only need to run the tests for that rule. These are usually what are called the yaml tests. This refers to a body of example sql statements and potential fixes defined in a large set of yaml files found in test/fixtures/rules/std_rule_cases. The easiest way to run these is by calling that part of the suite directly and filtering to just that rule. For example:
     • tox -e py39 -- test/rules/yaml_test_cases_test.py -k AL01
     • pytest test/rules/yaml_test_cases_test.py -k AL01
   • When developing on some more complicated rules, or ones known to have interactions with other rules, there are a set of rule fixing tests which apply a set combination of those rules. These are best run via the autofix tests. For example:
     • tox -e py39 -- test/rules/std_fix_auto_test.py
     • pytest test/rules/std_fix_auto_test.py
     • Potentially even the full rules suite tox -e py39 -- test/rules
   • A small number of core rules are also used in making sure that inner parts of SQLFluff are also functioning. This isn't great isolation but does mean that occasionally you may find side effects of your changes in the wider test suite. These can usually be caught by running the full tox -e py39 suite as a final check (or using the test suite on GitHub when posting your PR).
4. When developing the internals of SQLFluff (i.e. anything not already mentioned above), the test suite typically mirrors the structure of the internal submodules of sqlfluff:
   • When working with the CLI, the sqlfluff.cli module has a test suite called via tox -e py39 -- test/cli.
   • When working with the templaters (i.e. sqlfluff.core.templaters), the corresponding test suite is found via tox -e py39 -- test/core/templaters.
   • This rough guidance and may however not apply for all of the internals. For example, changes to the internals of the parsing module (sqlfluff.core.parser) are very likely to have knock-on implications across the rest of the test suite and it may be necessary to run the whole thing. In these situations however you can usually work slowly outward, for example:
     1. If your change is to the AnyOf() grammar, first running tox -e py39 -- test/core/parser/grammar_test.py would be wise.
     2. ...followed by tox -e py39 -- test/core/parser once the above is passing.
     3. ...and then tox -e py39 -- test/core.
     4. ...and finally the full suite tox -e py39.

dbt templater tests

The dbt templater tests require a locally running Postgres instance. See the required connection parameters in plugins/sqlfluff-templater-dbt/test/fixtures/dbt/profiles.yml. We recommend using https://postgresapp.com/.

To run the dbt-related tests you will have to explicitly include these tests:

tox -e cov-init,dbt018-py38,cov-report-dbt -- plugins/sqlfluff-templater-dbt

For more information on adding and running test cases see the Parser Test README and the Rules Test README.

Running dbt templater tests in Docker Compose

NOTE: If you prefer, you can develop and debug the dbt templater using a Docker Compose environment. It's a simple two-container configuration:

• app: Hosts the SQLFluff development environment. The host's source directory is mounted into the container, so you can iterate on code changes without having to constantly rebuild and restart the container.
• postgres: Hosts a transient Postgres database instance.

Steps to use the Docker Compose environment:

• Install Docker on your machine.
• Run plugins/sqlfluff-templater-dbt/docker/startup to create the containers.
• Run plugins/sqlfluff-templater-dbt/docker/shell to start a bash session in the app container.

Inside the container, run:

py.test -v plugins/sqlfluff-templater-dbt/test/

Pre-Commit Config

For development convenience we also provide a .pre-commit-config.yaml file to allow the user to install a selection of pre-commit hooks by running (check the requirements before running this):

tox -e pre-commit -- install

These hooks can help the user identify and fix potential linting/typing violations prior to committing their code and therefore reduce having to deal with these sort of issues during code review.

Documentation Website

Documentation is built using Sphinx with some pages being built based on the source code. See the Documentation Website README.md file for more information on how to build and test this.

Building Package

New versions of SQLFluff will be published to PyPI automatically via GitHub Actions whenever a new release is published to GitHub.

Release checklist:

The release page shows maintainers all merges since last release. Once we have a long enough list, we should prepare a release.

A release PR can be created by maintainers via the "Create release pull request" GitHub Action.

As further PRs are merged, we may need to rerun the release script again (or alternatively just manually updating the branch). This can only be rerun locally (the GitHub Action will exit error if the branch already exists to prevent overwriting it).

Check out the release branch created by the GitHub Action locally and run the script. It will preserve any Highlights you have added and update the other sections with new contributions. It can be run as follows (you will need a GitHub Personal Access Token with "repo" permission):

source .venv/bin/activate
export GITHUB_REPOSITORY_OWNER=sqlfluff
export GITHUB_TOKEN=gho_xxxxxxxx # Change to your token with "repo" permissions.
python util.py release 2.0.3 # Change to your release number

Below is the old list of release steps, but many are automated by the process described above.

• Change the version in setup.cfg and plugins/sqlfluff-templater-dbt/setup.cfg
• Update the stable_version in the [sqlfluff_docs] section of setup.cfg
• Copy the draft releases from https://github.com/sqlfluff/sqlfluff/releases to CHANGELOG.md. These draft release notes have been created by a GitHub Action on each PR merge.
• If you pretend to create a new draft in GitHub and hit "Auto Generate Release Notes", then it will basically recreate these notes (though in a slightly different format), but also add a nice "First contributors" section, so can copy that "First contributors" section too and then abandon that new draft (an issues has been raised to ask for this in Release Drafter GitHub Action).
• Add markdown links to PRs as annoyingly GitHub doesn't do this automatically when displaying Markdown files, like it does for comments. You can use regex in most code editors to replace \(#([0-9]*)\) @([^ ]*)$ to [#$1](https://github.com/sqlfluff/sqlfluff/pull/$1) [@$2](https://github.com/$2), or if using the GitHub generated release notes then can replace by @([^ ]*) in https://github.com/sqlfluff/sqlfluff/pull/([0-9]*)$ to [#$2](https://github.com/sqlfluff/sqlfluff/pull/$2) [@$1](https://github.com/$1).
• For the new contributors section, you can replace \* @([^ ]*) made their first contribution in https://github.com/sqlfluff/sqlfluff/pull/([0-9]*)$ with * [@$1](https://github.com/$1) made their first contribution in [#$2](https://github.com/sqlfluff/sqlfluff/pull/$2) to do this automatically).
• Check each issue title is clear, and if not edit issue title (which will automatically update Release notes on next PR merged, as the Draft one is recreated in full each time). We also don't use conventional commit PR titles (e.g. feat) so make them more English readable. Make same edits locally in CHANGELOG.md.
• Add a comment at the top to highlight the main things in this release.
• If this is a non-patch release then update the Notable changes section in index.rst with a brief summary of the new features added that made this a non-patch release.
• View the CHANGELOG in this branch on GitHub to ensure you didn't miss any link conversions or other markup errors.
• Open draft PR with those change a few days in advance to give contributors notice. Tag those with open PRs in the PR in GitHub to give them time to merge their work before the new release
• Comment in #contributing slack channel about release candidate.
• Update the draft PR as more changes get merged.
• Get another contributor to approve the PR.
• Merge the PR when looks like we've got all we’re gonna get for this release.
• Go to the releases page, edit the release to be same as CHANGELOG.md (remember to remove your release PR which doesn’t need to go in this). Add version tag and a title and click “Publish release”.
• Announce the release in the #general channel, with shout outs to those who contributed many, or big items.
• Announce the release on Twitter (@tunetheweb can do this or let him know your Twitter handle if you want access to Tweet on SQLFluff’s behalf).

⚠️ Before creating a new release, ensure that setup.cfg is up-to-date with a new version ⚠️. If this is not done, PyPI will reject the package. Also, ensure you have used that version as a part of the tag and have described the changes accordingly.

Releasing Manually

If for some reason the package needs to be submitted to PyPI manually, we use twine. You will need to be an admin to submit this to PyPI, and you will need a properly formatted .pypirc file. If you have managed all that then you can run:

tox -e publish-dist

... and the most recent version will be uploaded to PyPI.