check_commit_message

#!/usr/bin/env python
"""Checks that a commit message conforms the the style guide."""
import sys

# Get the commit message location
commit_msg_filepath = sys.argv[1]

# Extract the message lines into a list
lines = list((line.rstrip() for line in open(commit_msg_filepath, 'r')))

# Remove all commented lines
lines = [line for line in lines if len(line) == 0 or line[0] != '#']

# Skip if this is an automated backport
if len(lines) >= 2 and 'cherry picked from commit' in lines[-2]:
    sys.exit(0)

exit_code = 0

# Error: no commit message
if len(lines) == 0 or len(lines[0]) == 0:
    print('Error: commit message cannot be blank.')
    sys.exit(1)

# Error: invalid subject line length
if len(lines[0]) > 50:
    print('Error: your subject line must be within 50 characters.')
    exit_code = 1

# Error: subject line not capitalized
if lines[0][0].isalpha() and not lines[0][0].isupper():
    print('Error: your subject line must be capitalized.')
    exit_code = 1

# Error: subject line ends with period
if lines[0].endswith('.'):
    print('Error: your subject line cannot end with a period.')
    exit_code = 1

# No body paragraph
if len(lines) == 1:
    sys.exit(exit_code)

# Error: subject and body not separated by newline
if len(lines[1]) != 0:
    print('Error: you must separate your subject '
          'and body paragraph with a newline.')
    exit_code = 1

lines = lines[2:]

count = 0
for line in lines:
    count += 1
    # Ignore newline
    if len(line) == 0:
        continue

    # Ignore lines containing URLs, which can get long
    if 'http' in line:
        continue

    # Error: invalid body paragraph length
    if len(line) > 72:
        print('Error: line {} of your body paragraph '
              'must be wrapped to 72 characters:'.format(count))
        print('>> ' + line)
        exit_code = 1

sys.exit(exit_code)