pre-commit hook

pre-commit.py

#!/usr/bin/env python

import json
import subprocess
import sys


def against():
    try:
        subprocess.check_call("git rev-parse --verify HEAD".split())
        return "HEAD"
    except:
        return "4b825dc642cb6eb9a060e54bf8d69288fbee4904"


def check_json(filename):
    with open(filename, mode="r") as jf:
        try:
            json.load(jf)
        except Exception, e:
            print "{} failed verification:\n{}".format(filename, e)
            sys.exit(1)


def check_whitespace(version=None):
    """ inspired by https://github.com/mozilla/moz-git-tools """
    if not version:
        version = against()
    try:
        subprocess.check_call("git diff-index --check --cached {}".format(version).split())
    except subprocess.CalledProcessError:
        print "whitespace verification failed"
        sys.exit(1)


def staged_files():
    for filename in subprocess.check_output("git diff --name-only --staged --diff-filter=AM".split()).split():
        yield filename.strip()


def verify(filelist):
    for json_file in filter(lambda x: x.endswith(".json"), filelist):
        check_json(json_file)
    

if __name__ == '__main__':
    verify(staged_files())
    check_whitespace()