Usage

This library provides the Flake8 plugin flake8-encodings to identify incorrect use of encodings.

Flake8 codes

ENC00X: checks for open(), builtins.open and io.open().

Code	Description
ENC001	no encoding specified for ‘open’.
ENC002	’encoding=None’ used for ‘open’.
ENC003	no encoding specified for ‘open’ with unknown mode.
ENC004	’encoding=None’ used for ‘open’ with unknown mode.

ENC003 and ENC004 are used in cases where the encoding is omitted (or is explicitly None) but the mode cannot be determined. The file might be opened in binary mode, in which case the encoding argument is ignored, or in text mode, in which case an encoding should be given.

ENC01X: checks for configparser.ConfigParser.read().

Code	Description
ENC011	no encoding specified for ‘configparser.ConfigParser.read’.
ENC012	’encoding=None’ used for ‘configparser.ConfigParser.read’.

New in version 0.2.0.

Changed in version 0.4.0: These codes now require the classes extra to be installed 1.

ENC02X: checks for pathlib.Path.open(), read_text() and write_text().

Code	Description
ENC021	no encoding specified for ‘pathlib.Path.open’.
ENC022	’encoding=None’ used for ‘pathlib.Path.open’.
ENC023	no encoding specified for ‘pathlib.Path.read_text’.
ENC024	’encoding=None’ used for ‘pathlib.Path.read_text’.
ENC025	no encoding specified for ‘pathlib.Path.write_text’.
ENC026	’encoding=None’ used for ‘pathlib.Path.write_text’.

New in version 0.3.0.

Changed in version 0.4.0: These codes now require the classes extra to be installed 1.

1(1,2)

Install using python3 -m pip install flake8-encodings[classes]

Examples

# stdlib
import configparser

open("README.rst").read()  # ENC001 no encoding specified for 'open'.
open("README.rst", encoding=None).read()  # ENC002 'encoding=None' used for 'open'.
open("README.rst", mode="rb").read()  # OK
open("README.rst", mode="rb", encoding=None).read()  # OK


def foo(mode: str = 'r'):
    open("README.rst", mode=mode).read()  # ENC003 no encoding specified for 'open' with unknown mode.
    open("README.rst", mode=mode,
            encoding=None).read()  # ENC004 'encoding=None' used for 'open' with unknown mode.


def load_config(filename: str):
    cfg = configparser.ConfigParser()
    cfg.read(filename)  # ENC011
    # cfg.read(filename, encoding=None)  # ENC012


def manipulate_file(filename):
    path = pathlib.Path(filename)

    path.write_text("Hello world")  # ENC025

    with path.open('a') as fp:  # ENC021
        f.write("\nHello everyone")

    print(path.read_text(encoding=None))  # ENC024

Pre-commit hook

flake8-encodings can also be used as a pre-commit hook See pre-commit for instructions

Sample .pre-commit-config.yaml:

- repo: https://github.com/pycqa/flake8
  rev: 3.8.4
  hooks:
  - id: flake8
    additional_dependencies:
    - flake8-encodings==0.5.1