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Version: 2.17.x

flake8

The Flake8 Python linter (https://flake8.pycqa.org/).

Backend: pants.backend.python.lint.flake8

Config section: [flake8]

Basic options​

skip​

--[no-]flake8-skip
PANTS_FLAKE8_SKIP
default: False

If true, don't use Flake8 when running scie-pants-linux-x86_64 lint.

args​

--flake8-args="[<shell_str>, <shell_str>, ...]"
PANTS_FLAKE8_ARGS
default: []

Arguments to pass directly to Flake8, e.g. --flake8-args='--ignore E123,W456 --enable-extensions H111'.

Advanced options​

install_from_resolve​

--flake8-install-from-resolve=<str>
PANTS_FLAKE8_INSTALL_FROM_RESOLVE
default: None

If specified, install the tool using the lockfile for this named resolve.

This resolve must be defined in [python].resolves, as described in https://www.pantsbuild.org/v2.17/docs/python-third-party-dependencies#user-lockfiles.

The resolve's entire lockfile will be installed, unless specific requirements are listed via the requirements option, in which case only those requirements will be installed. This is useful if you don't want to invalidate the tool's outputs when the resolve incurs changes to unrelated requirements.

If unspecified, and the lockfile option is unset, the tool will be installed using the default lockfile shipped with Pants.

If unspecified, and the lockfile option is set, the tool will use the custom flake8 "tool lockfile" generated from the version and extra_requirements options. But note that this mechanism is deprecated.

requirements​

--flake8-requirements="['<str>', '<str>', ...]"
PANTS_FLAKE8_REQUIREMENTS
default: []

If install_from_resolve is specified, install these requirements, at the versions provided by the specified resolve's lockfile.

Values can be pip-style requirements (e.g., tool or tool==1.2.3 or tool>=1.2.3), or addresses of python_requirement targets (or targets that generate or depend on python_requirement targets).

The lockfile will be validated against the requirements - if a lockfile doesn't provide the requirement (at a suitable version, if the requirement specifies version constraints) Pants will error.

If unspecified, install the entire lockfile.

console_script​

--flake8-console-script=<str>
PANTS_FLAKE8_CONSOLE_SCRIPT
default: flake8

The console script for the tool. Using this option is generally preferable to (and mutually exclusive with) specifying an --entry-point since console script names have a higher expectation of staying stable across releases of the tool. Usually, you will not want to change this from the default.

entry_point​

--flake8-entry-point=<str>
PANTS_FLAKE8_ENTRY_POINT
default: None

The entry point for the tool. Generally you only want to use this option if the tool does not offer a --console-script (which this option is mutually exclusive with). Usually, you will not want to change this from the default.

config​

--flake8-config=<file_option>
PANTS_FLAKE8_CONFIG
default: None

Path to an INI config file understood by Flake8 (https://flake8.pycqa.org/en/latest/user/configuration.html).

Setting this option will disable [flake8].config_discovery. Use this option if the config is located in a non-standard location.

extra_files​

--flake8-extra-files="[<file_option>, <file_option>, ...]"
PANTS_FLAKE8_EXTRA_FILES
default: []

Paths to extra files to include in the sandbox. This can be useful for Flake8 plugins,

        like including config files for the `flake8-bandit` plugin.

config_discovery​

--[no-]flake8-config-discovery
PANTS_FLAKE8_CONFIG_DISCOVERY
default: True

If true, Pants will include any relevant config files during runs (.flake8, flake8, setup.cfg, and tox.ini).

Use [flake8].config instead if your config is in a non-standard location.

source_plugins​

--flake8-source-plugins="[<target_option>, <target_option>, ...]"
PANTS_FLAKE8_SOURCE_PLUGINS
default: []

An optional list of python_sources target addresses to load first-party plugins.

You must set the plugin's parent directory as a source root. For example, if your plugin is at build-support/flake8/custom_plugin.py, add 'build-support/flake8' to [source].root_patterns in pants.toml. This is necessary for Pants to know how to tell Flake8 to discover your plugin. See https://www.pantsbuild.org/v2.17/docs/source-roots

You must also set [flake8:local-plugins] in your Flake8 config file.

For example:

[flake8:local-plugins]
    extension =
        CUSTOMCODE = custom_plugin:MyChecker

While your plugin's code can depend on other first-party code and third-party requirements, all first-party dependencies of the plugin must live in the same directory or a subdirectory.

To instead load third-party plugins, set the option [flake8].extra_requirements.

Tip: it's often helpful to define a dedicated 'resolve' via [python].resolves for your Flake8 plugins such as 'flake8-plugins' so that the third-party requirements used by your plugin, like flake8, do not mix with the rest of your project. Read that option's help message for more info on resolves.

Deprecated options​

version​

--flake8-version=<str>
PANTS_FLAKE8_VERSION
default: flake8>=5.0.4,<7

Requirement string for the tool.

extra_requirements​

--flake8-extra-requirements="['<str>', '<str>', ...]"
PANTS_FLAKE8_EXTRA_REQUIREMENTS
default: []

Any additional requirement strings to use with the tool. This is useful if the tool allows you to install plugins or if you need to constrain a dependency to a certain version.

lockfile​

--flake8-lockfile=<str>
PANTS_FLAKE8_LOCKFILE
default: <default>

Path to a lockfile used for installing the tool.

Set to the string <default> to use a lockfile provided by Pants, so long as you have not changed the --version and --extra-requirements options, and the tool's interpreter constraints are compatible with the default. Pants will error or warn if the lockfile is not compatible (controlled by [python].invalid_lockfile_behavior). See https://github.com/pantsbuild/pants/blob/release_2.17.1rc3/src/python/pants/backend/python/lint/flake8/flake8.lock for the default lockfile contents.

To use a custom lockfile, set this option to a file path relative to the build root, then run scie-pants-linux-x86_64 generate-lockfiles --resolve=flake8.

Alternatively, you can set this option to the path to a custom lockfile using pip's requirements.txt-style, ideally with --hash. Set [python].invalid_lockfile_behavior = 'ignore' so that Pants does not complain about missing lockfile headers.

export​

--[no-]flake8-export
PANTS_FLAKE8_EXPORT
default: True

If true, export a virtual environment with Flake8 when running scie-pants-linux-x86_64 export.

This can be useful, for example, with IDE integrations to point your editor to the tool's binary.