hgext/win32text.py

Issue 882: add standard hook to reject text files with CRLF.
While the win32text extension does LF <-> CRLF conversion, and will issue a
warning in case a file already in the repository uses CRLF, it provides no
mechanism for verifying that incoming changes use LF. In a large development
team with some Windows users, it is virtually guaranteed that someone will
forget to set up the encode filter correctly and accidentally check in a file
using CRLF, which can cause warnings for other Windows users when they next
fetch changes. Since this is a general problem it is desirable to have a
pre-commit (or -push) hook available to reject such accidents earlier rather
than trying to fix them up after the fact.

# win32text.py - LF <-> CRLF translation utilities for Windows users
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
#
# To perform automatic newline conversion, use:
#
# [extensions]
# hgext.win32text =
# [encode]
# ** = cleverencode:
# [decode]
# ** = cleverdecode:
#
# If not doing conversion, to make sure you do not commit CRLF by accident:
#
# [hooks]
# pretxncommit.crlf = python:hgext.win32text.forbidcrlf
#
# To do the same check on a server to prevent CRLF from being pushed or pulled:
#
# [hooks]
# pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf

from mercurial import util, ui
from mercurial.i18n import gettext as _
from mercurial.node import *
import re

# regexp for single LF without CR preceding.
re_single_lf = re.compile('(^|[^\r])\n', re.MULTILINE)

def dumbdecode(s, cmd):
    # warn if already has CRLF in repository.
    # it might cause unexpected eol conversion.
    # see issue 302:
    #   http://www.selenic.com/mercurial/bts/issue302
    if '\r\n' in s:
        u = ui.ui()
        u.warn(_('WARNING: file in repository already has CRLF line ending \n'
                 ' which does not need eol conversion by win32text plugin.\n'
                 ' Please reconsider encode/decode setting in'
                 ' mercurial.ini or .hg/hgrc\n'
                 ' before next commit.\n'))
    # replace single LF to CRLF
    return re_single_lf.sub('\\1\r\n', s)

def dumbencode(s, cmd):
    return s.replace('\r\n', '\n')

def clevertest(s, cmd):
    if '\0' in s: return False
    return True

def cleverdecode(s, cmd):
    if clevertest(s, cmd):
        return dumbdecode(s, cmd)
    return s

def cleverencode(s, cmd):
    if clevertest(s, cmd):
        return dumbencode(s, cmd)
    return s

util.filtertable.update({
    'dumbdecode:': dumbdecode,
    'dumbencode:': dumbencode,
    'cleverdecode:': cleverdecode,
    'cleverencode:': cleverencode,
    })

def forbidcrlf(ui, repo, hooktype, node, **kwargs):
    halt = False
    for rev in xrange(repo.changelog.rev(bin(node)), repo.changelog.count()):
        c = repo.changectx(rev)
        for f in c.files():
            if f not in c:
                continue
            data = c[f].data()
            if '\0' not in data and '\r\n' in data:
                if not halt:
                    ui.warn(_('Attempt to commit or push text file(s) '
                              'using CRLF line endings\n'))
                ui.warn(_('in %s: %s\n') % (short(c.node()), f))
                halt = True
    if halt and hooktype == 'pretxnchangegroup':
        ui.warn(_('\nTo prevent this mistake in your local repository,\n'
                  'add to Mercurial.ini or .hg/hgrc:\n'
                  '\n'
                  '[hooks]\n'
                  'pretxncommit.crlf = python:hgext.win32text.forbidcrlf\n'
                  '\n'
                  'and also consider adding:\n'
                  '\n'
                  '[extensions]\n'
                  'hgext.win32text =\n'
                  '[encode]\n'
                  '** = cleverencode:\n'
                  '[decode]\n'
                  '** = cleverdecode:\n'))
    return halt