git-patch-to-hg-patch


          
            
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            #!/usr/bin/env python

r"""Git format-patch to hg importable patch.

(Who knew this was so complicated?)

>>> process(StringIO('From 3ce1ccc06 Mon Sep 17 00:00:00 2001\nFrom: fromuser\nSubject: subject\n\nRest of patch.\nMore patch.\n'))
'# HG changeset patch\n# User fromuser\n\nsubject\n\nRest of patch.\nMore patch.\n'

>>> process(StringIO('From: fromuser\nSubject: A very long subject line.  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi faucibus, arcu sit amet\n\nRest of patch.\nMore patch.\n'))
'# HG changeset patch\n# User fromuser\n\nA very long subject line.  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi faucibus, arcu sit amet\n\nRest of patch.\nMore patch.\n'

>>> process(StringIO('From: f\nSubject: =?UTF-8?q?Bug=20655877=20-=20Dont=20treat=20SVG=20text=20frames=20?= =?UTF-8?q?as=20being=20positioned.=20r=3D=3F?=\n\nPatch.'))
'# HG changeset patch\n# User f\n\nBug 655877 - Dont treat SVG text frames as being positioned. r=?\n\nPatch.'
"""

# Original author: bholley

import sys
import re
import fileinput
import email, email.parser, email.header
import math
from cStringIO import StringIO
from itertools import takewhile

def decode_header(hdr_string):
  r"""Clean up weird encoding crap.

  >>> clean_header('[PATCH] =?UTF-8?q?Bug=20655877=20r=3D=3F?=')
  '[PATCH] Bug 655877 r=?'
  """
  rv = []
  hdr = email.header.Header(hdr_string, maxlinelen=float('inf'))
  for (part, encoding) in email.header.decode_header(hdr):
    if encoding is None:
      rv.append(part)
    else:
      rv.append(part.decode(encoding).encode('utf-8'))
  return ' '.join(rv)

def clean_header(hdr_string):
  r"""Transform a header split over many lines into a header split only where
  linebreaks are intended.  This is important because hg cares about the first
  line of the commit message.
  
  Also clean up weird encoding crap.
  
  >>> clean_header('Foo\n bar\n baz')
  'Foo bar baz'
  >>> clean_header('Foo\n bar\nSpam\nEggs')
  'Foo bar\nSpam\nEggs'
  """

  lines = []
  curline = ''
  for line in decode_header(hdr_string).split('\n'):
    if not line.startswith(' '):
      lines.append(curline)
      curline = ''
    curline += line
  lines.append(curline)
  return '\n'.join(lines[1:])

def process(git_patch_file):
  parser = email.parser.Parser()
  msg = parser.parse(git_patch_file)

  return '\n'.join(['# HG changeset patch',
                    '# User ' + clean_header(msg['From']),
                    '',
                    clean_header(msg['subject']),
                    '',
                    msg.get_payload()])

  # Decode the header into a UTF-8 string, in case it uses MIME encoded words
  encoded_subject = Header(subject)
  subject = ''
  for (part, encoding) in decode_header(encoded_subject):
    if encoding is None:
      subject += part
    else:
      subject += part.decode(encoding).encode('utf-8')

  # Filter a version (ie, v3, v12) out of the subject.
  subject = re.sub(r'\s?v\d\d?', '', subject)

  # Write the header.
  return ['# HG changeset patch\n', author, '\n', subject, '\n'] + list(iterlines)

if __name__ == "__main__":
  if len(sys.argv) > 1 and sys.argv[1] == '--test':
    import doctest
    doctest.testmod()
    sys.exit(0)

  # If there were no arguments, do stdin->stdout.
  filelist = sys.argv[1:]
  if not filelist:
    lines = process(sys.stdin)
    sys.stdout.writelines(lines)
    sys.exit(0)

  # Otherwise, we take a list of files.
  for filename in filelist:

    # Read the lines.
    f = open(filename, 'r')
    lines = process(f)
    f.close()

    # Process.

    # Write them back to the same file.
    f = open(filename, 'w')
    f.writelines(lines)
    f.close()