A flake8 extension that checks for blind, catch-all
except Exception: statements.
As of pycodestyle 2.1.0, "E722 do not use bare except, specify exception instead" is built-in. However, bare
BaseException are still allowed. This extension flags them as B902.
except without explicitly specifying which exceptions to catch is generally considered bad practice, since it catches system signals like
SIGINT. You probably want to handle system interrupts differently than exceptions occuring in your code.
It's also usually better style to have many small
except blocks catching specific exceptions instead of a giant
try: block with a catch-all
except: at the bottom. It's also nicer to your fellow programmers to be a bit more specific about what exceptions they can expect in specific parts of the code, and what the proper course of action is when they occur.
An example of code that will fail this check is:
try: something_scary() except: everybody_panic()
However, the following code is valid:
try: something_terrifying() except TerrifyingException: dont_panic()
If you don't already have it, install
$ pip install flake8
Then, install the extension:
$ pip install flake8-blind-except
Run the following to verify that the plugin has been installed correctly:
$ flake8 --version 2.0 (pep8: 1.4.6, flake8-blind-except: 0.1.0, pyflakes: 0.7.3)
Now, when you run
flake8, the plugin will automatically be used.
When a blind except is found,
flake8 will output:
B901 blind except: statement
B902 blind except Exception: statement
I'm not working on Python these days, so probably won't be making updates anytime soon. PRs are welcome though!
Tests can be run with
pytest --doctest-modules flake8_blind_except.py.
0.2.0 - 2021-01-07
- B902 error added for cases where a blind
0.1.1 - 2016-06-27
pep8was renamed to
pycodestylein its 2.0 release. Compatibility update for this change.
0.1.0 - 2014-02-07
- Initial release
I've tested this package with flake8 2.6.2 + Python 2.7.3 and flake8 3.7.9 + Python 3.7.5.