Checkstyle pre-commit hook

checkstyle-pre-commit.py

#! /usr/bin/env python
# -*- encoding: utf-8 -*-

import os

# Config
checkstyle_jar = os.getenv('CHECKSTYLE_JAR', "checkstyle-5.7-all.jar")
checkstyle_cfg = os.getenv('CHECKSTYLE_CFG', "checkstyle.xml")

failing_test_should_prevent_commit = True

# Limit Checkstyle test to new classes only. You can use the following 
# template: 
#    
#     export CHECKSTYLE_START_DATE='2014-01-01 00:00:00 +0200'
#
min_date_of_first_commit = os.getenv('CHECKSTYLE_START_DATE', None)

java_cmd = "java"
git_cmd = "git"

# Init
import datetime
import re
import subprocess 
import sys

def parse_date(val):
    # We're not using python-dateutil, since it's not available out of the box on some machines
    m = re.match('[0-9]{4}-[0-9]{2}-[0-9]{2}', val)
    if m:
        return datetime.datetime.strptime(m.group(0), '%Y-%m-%d')
    else:
        raise Exception("Invalid date format: %s" % val)

try:
    import colorama
    
    colorama.init()
    
    style_ok = colorama.Fore.GREEN
    style_err = colorama.Fore.RED
    style_warn = colorama.Fore.YELLOW
    style_details = colorama.Style.DIM
    style_reset = colorama.Style.RESET_ALL
except ImportError as err:
    # Colorama dependency is optional, since some people may not be able to install it locally
    style_ok = "" 
    style_err = ""
    style_warn = "" 
    style_details = "" 
    style_reset = ""

if not os.path.isfile(checkstyle_jar):
    sys.stderr.write("checkstyle JAR not found (%s)\n" % checkstyle_jar)
    sys.exit(1)

if not os.path.isfile(checkstyle_cfg):
    sys.stderr.write("checkstyle config not found (%s)\n" % checkstyle_cfg)
    sys.exit(1)

if "check_output" not in dir( subprocess ):
    sys.stderr.write("python >= 2.7 is required\n")
    sys.exit(1)

if min_date_of_first_commit is not None:
     min_date_of_first_commit = parse_date(min_date_of_first_commit)

# Fetch files to commit
file_list = subprocess.check_output([git_cmd, "diff", "--cached", "--name-only", "--diff-filter=ACM"])
file_list = [f for f in file_list.splitlines() if f.endswith('.java')]

# Run Checkstyle
def first_commit_before_date(source_file, dt):
    commits = subprocess.check_output([git_cmd, "log", "--format=%ai", source_file])
    if len(commits) == 0:
        return False
    first_commit = commits.splitlines()[-1]
    first_commit = parse_date(first_commit)
    return first_commit < dt

failed_checks = 0
for source_file in file_list:
    if min_date_of_first_commit is not None and first_commit_before_date(source_file, min_date_of_first_commit):
        print "Checkstyle: " + source_file + style_warn + " SKIPPED (too old)" + style_reset
        continue 

    try:
        subprocess.check_output([java_cmd, "-jar", checkstyle_jar, "-c", checkstyle_cfg, source_file])
        print 'Checkstyle: ' + source_file + style_ok + ' OK' + style_reset 
    except subprocess.CalledProcessError as err:
        failed_checks = failed_checks + 1
        print 'Checkstyle: ' + source_file + style_err + ' FAILED' + style_reset 
        # Print Checkstyle details
        checkRegexp = re.compile(r'\.java:')
	messages = [checkRegexp.split(m)[-1] for m in err.output.splitlines() if checkRegexp.search(m) is not None]
	for m in messages:
	    print ' => ' + style_details + m + style_reset 

# Decisions
if failed_checks == 0:
    print "%d Checkstyle tests passed" % len(file_list)
elif failing_test_should_prevent_commit:
    print style_err + "%d Checkstyle tests failed" % failed_checks + style_reset 
    sys.exit(2)
else:
    print style_warn + "%d Checkstyle tests failed (won't block the commit)" % failed_checks + style_reset 
    sys.exit(0)