Regex blacklist for git diff in git pre-commit hook

pre-commit

#!/usr/bin/env python
from subprocess import *
import sys
import re

# Add Regex to blacklist here
blacklist = [
  "\+[ ]+NSLog.+"  # Prevent NSLog's from being added
]

def matches_blacklisted_regex(text):
  return len(re.findall("|".join(blacklist), text)) > 0

def compile_pattern():
  # Always check for 'diff' and '@@' so we know which file and lines contain 
  # the blacklisted code
  regex = r"^diff.*|^@@.*|" + "|".join(blacklist)
  return re.compile(regex, re.MULTILINE)


# Print the diff displaying only the lines containing illegal statements
def print_filtered_diff(diff_output):
  pattern = compile_pattern()
  res = pattern.findall( str(diff_output) )
  for r in res:
    # Insert extra newline for clarity
    if r.startswith("diff"):
      print ""
    print r


def check_blacklist():
  # --no-color or else regex won't work properly
  diff_output = Popen(["git", "diff","--no-color"], stdout=PIPE).communicate()[0]
  if ( matches_blacklisted_regex(diff_output) ):
    print ""
    print "WARNING: git diff contains blacklisted code"
    print "-------------------------------------------"
    print_filtered_diff(diff_output)
    print ""
    sys.exit(1)


check_blacklist()