Pre-commit Hook

PEP8 Version

A couple of days ago I’ve refactored and enhanced my pre-commit hook to check also for PEP8 compliancy of Python source files. To achieve this I used the pep8 tool that you can easily install with:

pip install pep8

And here’s the new pre-commit hook:

#!/bin/bash
#
# TAB CHECK:
#
# Searches tab characters in staged changes.
# To specify file extensions to check use "hooks.notabs" variable.
# Extensions are separated by "|".
# Eg:
#   git config hooks.notabs html|js
#
# PEP8 CHECK:
#
# run pep8 on all python staged files.
# To specify pep8 command options use "hook.pep8options" variable
#
# Eg:
#   git config hook.pep8 "--ignore=E226,E302"

exec 1>&2

notabs=$(git config hooks.notabs)
notabs_error=0
for f in `git diff --cached --name-only | egrep "\.("$notabs")$"`
do
    lines=`git show :$f | fgrep -n $'\t'`
    if [ -n "$lines" ]; then
        echo "TAB(s) found in:" $f "at line(s)"
        echo $lines
        notabs_error=1
    fi
done

if [ $notabs_error -eq 1 ]; then
    echo
    echo "Remove all TAB(s) characters and stage again your changes."
    echo
    exit 1
fi

pep8_options=$(git config hooks.pep8options)
pep8_error=0
for f in `git diff --cached --name-only | egrep ".py$"`
do
    git show :$f | pep8 --format=$f":%(row)d:%(col)d: %(code)s %(text)s" $pep8_options -
    if [ $? -eq 1 ]; then
        pep8_error=1
    fi
done

if [ $pep8_error -eq 1 ]; then
    echo
    echo "Your commit is cause of one or more PEP8 error(s)"
    echo
    echo "Please fix these errors and stage again your changes"
    echo
    exit 1
fi

This new version is quite straightforward so I’m not digging too much into it. The two main changes are:

• Discover of command git show :)
• Add pep8 style test

About the latter point, it’s important to say that the pep8 has becomes one of the requirements to use this hook. Also, you can configure your pep8 options by typing:

git config --add hooks.pep8options "--ignore=E121,E122" # this ignores Error 121, 122

A complete list of errors and warnings of pep8 tool is available here: http://pep8.readthedocs.org/en/latest/intro.html#error-codes

PS.

I’m using this hook just from a couple of days, so it may (probably) have some bugs… feel free to contribute at https://github.com/cybercase/funproject/blob/master/experiments/pre-commit ;)

— 15/09/2013