flake8-raise

A flake8 plugin that finds improvements for raise statements.

Installation

Install using pip:

$ pip install flake8-raise

When installed, the plugin will automatically be used by flake8. To check it is installed correctly, run flake8 --version and look in the list of installed plugins:

$ flake8 --version
3.7.9 (flake8-raise: 0.0.5, mccabe: 0.6.1, pycodestyle: 2.5.0, pyflakes: 2.1.1) CPython 3.8.1 on Linux

Rules

Code	Rule
R100	raise in except handler without from
R101	use bare raise in except handler
R102	unnecessary parentheses on raised exception

Examples

R100 raise in except handler without from

try:
    foo["bar"]
except KeyError:
    raise MyException

Will result in the error:

R100 raise in except handler without from.

To fix, change to:

try:
    foo['bar']
except KeyError as e:
    raise MyException from e

R101 use bare raise in except handler

try:
    foo["bar"]
except KeyError as e:
    raise e

Will result in the error:

R101 Use bare raise in except handler.

To fix, change to:

try:
    foo['bar']
except KeyError:
    raise

R102 unnecessary parentheses on raised exception

raise TypeError()

Will result in the error:

R102 unnecessary parentheses on raised exception

To fix, change to:

raise TypeError