Enabling

Simply defining a linter does not enable it. Trunk needs to know when to auto-enable the linter for certain projects (ex: all python projects) or if certain files are already present (ex: .eslintrc).

Auto Enabling

The direct_configs property contains a list of config files that the underlying linter uses. The suggest_if property determines when trunk check should suggest this linter. If suggest_if is set to config_present, then trunk will search for the listed config files. If found, the linter will be enabled automatically when the user does trunk init or trunk update.

For example: in the following yaml, the flake8 linter sets suggest_if to config_preset and sets direct_configs to [.flake8]. If any *.flake8 files are found, then trunk check will automatically enable flake8.

Flake8 linter definition. full source

version: 0.1
tools:
  definitions:
    - name: flake8
      runtime: python
      package: flake8
      shims: [flake8]
      known_good_version: 4.0.1
lint:
  definitions:
    - name: flake8
      files: [python]
      tools: [flake8]
      direct_configs: [.flake8]
      suggest_if: config_present
      affects_cache:
        - setup.cfg
        - tox.ini
        # In case the user installs https://pypi.org/project/Flake8-pyproject/
        - pyproject.toml
      issue_url_format: https://flake8.pycqa.org/en/latest/user/error-codes.html
      known_good_version: 4.0.1
      version_command:
        parse_regex: ${semver}
        run: flake8 --version

The suggest_if field can be one of the following:

• config_present will auto-enable a linter if Trunk sees any direct_config for it .

• files_present will auto-enable a linter if Trunk sees any file type that it operates on.

• never will never auto-enable this linter.

Trunk curates the values of suggest_if for all linters in the plugins repo.

Manually enabling and disabling

Setting the lint.definitions[*].enabled property to true will force the linter to be enabled. Setting the lint.definitions[*].disabled property to true will force the linter to never be enabled, even if the enabled property is true, and will never suggest this linter, even if suggest_if says it should.

For additional information on the properties of Linters, see the Linter Definition Reference.