flake8-literal

flake8 plugin to validate string literals.

This plugin is used to enforce consistent styling of string literals, it recognizes inline literals, multline literals, and docstrings.

Quote Usage

You can choose between single or double quotes for each type of string, and the plugin will enforce consistent usage.

If the avoid-escape feature is on (default), it will enforce using the opposite quote type when doing so will avoid the use of escaped quotes.

It also recognizes continuation strings and will enforce a consistent quote style for the entire set when possible.

Raw Strings

This plugin checks the usage of raw strings, preventing unnecessary use of raw strings, and requiring raw strings when doing so will avoid an escaped backslash.

Because raw strings are commonly used in regular expression patterns, otherwise unnecessary raw strings are allowed by default when used as a regular expression pattern. There is an option to avoid raw strings in regular expression patterns, or to require them regardless of the presence of escapes. Note that this feature only works when using string literals directly in calls to re functions, and the functions must be called in the manner that they are imported. e.g.

from re import compile as regex_compile
x = regex_compile(r'this does not need to be raw')

would be acceptable, but

import re
pattern = r'this does not need to be raw'
x = re.compile(pattern)

or

import re
regex_compile = re.compile
y = regex_compile(r'this does not need to be raw')

would not.

Planned Features

• Enforcing multiline string usage
• String concatenation
• Format string usage

Installation

Standard python package installation:

pip install flake8-literal

Options

literal-inline-quotes : Quote to use for inline string literals, choices: single, double (default: single)

literal-multiline-quotes : Quote to use for multiline string literals, choices: single, double (default: single)

literal-docstring-quotes : Quote to use for docstrings, choices: single, double (default: double)

literal-avoid-escape : Avoid escapes in inline string literals when possible (enabled by default)

literal-no-avoid-escape : Disable escape avoidance in inline string literals

literal-re-pattern-raw : Control usage of raw string literals in regular expression patterns, choices avoid, allow, always (default: allow)

literal-include-name : Include plugin name in messages

literal-no-include-name : Do not include plugin name in messages (default setting)

All options may be specified on the command line with a -- prefix, or can be placed in your flake8 config file.

Error Codes

Code	Message
LIT001	Use single quotes for string
LIT002	Use double quotes for string
LIT003	Use single quotes for multiline string
LIT004	Use double quotes for multiline string
LIT005	Use single quotes for docstring
LIT006	Use double quotes for docstring
LIT007	Use triple single quotes for docstring
LIT008	Use triple double quotes for docstring
LIT011	Use double quotes for string to avoid escaped single quote
LIT012	Use single quotes for string to avoid escaped double quote
LIT013	Escaped single quote is not necessary
LIT014	Escaped double quote is not necessary
LIT015	Use double quotes for continuation strings to match
LIT016	Use single quotes for continuation strings to match
LIT101	Remove raw prefix when not using escapes
LIT102	Use raw prefix to avoid escaped slash
LIT103	Use raw prefix for re pattern

Examples

x = "value"  <-- LIT001
x = 'aren\'t escapes great?'  <-- LIT011
x = "can\'t stop escaping"  <-- LIT013
x = ('one'  <-- LIT015
     "o'clock")
x = r'no need to be raw'  <-- LIT101
x = '\\windows\\path'  <-- LIT102
x = re.compile(r'pattern')  <-- (no error when literal-re-pattern-raw set to `allow` or `always`)
x = re.compile('pattern')  <-- LIT103 (when literal-re-pattern-raw set to `always`)