mdw@git.distorted.org.uk Git - stgit/blob - stgit/gitmergeonefile.py

   1 """Performs a 3-way merge for GIT files
   2 """
   3
   4 __copyright__ = """
   5 Copyright (C) 2006, Catalin Marinas <catalin.marinas@gmail.com>
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License version 2 as
   9 published by the Free Software Foundation.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 """
  20
  21 import sys, os
  22 from stgit.config import config
  23 from stgit.utils import append_string
  24
  25
  26 class GitMergeException(Exception):
  27     pass
  28
  29
  30 #
  31 # Options
  32 #
  33 try:
  34     merger = config.get('stgit', 'merger')
  35     keeporig = config.get('stgit', 'keeporig')
  36 except Exception, err:
  37     raise GitMergeException, 'Configuration error: %s' % err
  38
  39
  40 #
  41 # Utility functions
  42 #
  43 def __str2none(x):
  44     if x == '':
  45         return None
  46     else:
  47         return x
  48
  49 def __output(cmd):
  50     f = os.popen(cmd, 'r')
  51     string = f.readline().rstrip()
  52     if f.close():
  53         raise GitMergeException, 'Error: failed to execute "%s"' % cmd
  54     return string
  55
  56 def __checkout_files(orig_hash, file1_hash, file2_hash,
  57                      path,
  58                      orig_mode, file1_mode, file2_mode):
  59     """Check out the files passed as arguments
  60     """
  61     global orig, src1, src2
  62
  63     if orig_hash:
  64         orig = '%s.older' % path
  65         tmp = __output('git-unpack-file %s' % orig_hash)
  66         os.chmod(tmp, int(orig_mode, 8))
  67         os.renames(tmp, orig)
  68     if file1_hash:
  69         src1 = '%s.local' % path
  70         tmp = __output('git-unpack-file %s' % file1_hash)
  71         os.chmod(tmp, int(file1_mode, 8))
  72         os.renames(tmp, src1)
  73     if file2_hash:
  74         src2 = '%s.remote' % path
  75         tmp = __output('git-unpack-file %s' % file2_hash)
  76         os.chmod(tmp, int(file2_mode, 8))
  77         os.renames(tmp, src2)
  78
  79 def __remove_files(orig_hash, file1_hash, file2_hash):
  80     """Remove any temporary files
  81     """
  82     if orig_hash:
  83         os.remove(orig)
  84     if file1_hash:
  85         os.remove(src1)
  86     if file2_hash:
  87         os.remove(src2)
  88     pass
  89
  90 # GIT_DIR value cached
  91 __base_dir = None
  92
  93 def __conflict(path):
  94     """Write the conflict file for the 'path' variable and exit
  95     """
  96     global __base_dir
  97
  98     if not __base_dir:
  99         if 'GIT_DIR' in os.environ:
 100             __base_dir = os.environ['GIT_DIR']
 101         else:
 102             __base_dir = __output('git-rev-parse --git-dir')
 103
 104     append_string(os.path.join(__base_dir, 'conflicts'), path)
 105
 106
 107 #
 108 # Main algorithm
 109 #
 110 def merge(orig_hash, file1_hash, file2_hash,
 111           path,
 112           orig_mode, file1_mode, file2_mode):
 113     """Three-way merge for one file algorithm
 114     """
 115     __checkout_files(orig_hash, file1_hash, file2_hash,
 116                      path,
 117                      orig_mode, file1_mode, file2_mode)
 118
 119     # file exists in origin
 120     if orig_hash:
 121         # modified in both
 122         if file1_hash and file2_hash:
 123             # if modes are the same (git-read-tree probably dealt with it)
 124             if file1_hash == file2_hash:
 125                 if os.system('git-update-index --cacheinfo %s %s %s'
 126                              % (file1_mode, file1_hash, path)) != 0:
 127                     print >> sys.stderr, 'Error: git-update-index failed'
 128                     __conflict(path)
 129                     return 1
 130                 if os.system('git-checkout-index -u -f -- %s' % path):
 131                     print >> sys.stderr, 'Error: git-checkout-index failed'
 132                     __conflict(path)
 133                     return 1
 134                 if file1_mode != file2_mode:
 135                     print >> sys.stderr, \
 136                           'Error: File added in both, permissions conflict'
 137                     __conflict(path)
 138                     return 1
 139             # 3-way merge
 140             else:
 141                 merge_ok = os.system(merger % {'branch1': src1,
 142                                                'ancestor': orig,
 143                                                'branch2': src2,
 144                                                'output': path }) == 0
 145
 146                 if merge_ok:
 147                     os.system('git-update-index -- %s' % path)
 148                     __remove_files(orig_hash, file1_hash, file2_hash)
 149                     return 0
 150                 else:
 151                     print >> sys.stderr, \
 152                           'Error: three-way merge tool failed for file "%s"' \
 153                           % path
 154                     # reset the cache to the first branch
 155                     os.system('git-update-index --cacheinfo %s %s %s'
 156                               % (file1_mode, file1_hash, path))
 157                     if keeporig != 'yes':
 158                         __remove_files(orig_hash, file1_hash, file2_hash)
 159                     __conflict(path)
 160                     return 1
 161         # file deleted in both or deleted in one and unchanged in the other
 162         elif not (file1_hash or file2_hash) \
 163                or file1_hash == orig_hash or file2_hash == orig_hash:
 164             if os.path.exists(path):
 165                 os.remove(path)
 166             __remove_files(orig_hash, file1_hash, file2_hash)
 167             return os.system('git-update-index --remove -- %s' % path)
 168         # file deleted in one and changed in the other
 169         else:
 170             # Do something here - we must at least merge the entry in
 171             # the cache, instead of leaving it in U(nmerged) state. In
 172             # fact, stg resolved does not handle that.
 173
 174             # Do the same thing cogito does - remove the file in any case.
 175             os.system('git-update-index --remove -- %s' % path)
 176
 177             #if file1_hash:
 178                 ## file deleted upstream and changed in the patch. The
 179                 ## patch is probably going to move the changes
 180                 ## elsewhere.
 181
 182                 #os.system('git-update-index --remove -- %s' % path)
 183             #else:
 184                 ## file deleted in the patch and changed upstream. We
 185                 ## could re-delete it, but for now leave it there -
 186                 ## and let the user check if he still wants to remove
 187                 ## the file.
 188
 189                 ## reset the cache to the first branch
 190                 #os.system('git-update-index --cacheinfo %s %s %s'
 191                 #          % (file1_mode, file1_hash, path))
 192             __conflict(path)
 193             return 1
 194
 195     # file does not exist in origin
 196     else:
 197         # file added in both
 198         if file1_hash and file2_hash:
 199             # files are the same
 200             if file1_hash == file2_hash:
 201                 if os.system('git-update-index --add --cacheinfo %s %s %s'
 202                              % (file1_mode, file1_hash, path)) != 0:
 203                     print >> sys.stderr, 'Error: git-update-index failed'
 204                     __conflict(path)
 205                     return 1
 206                 if os.system('git-checkout-index -u -f -- %s' % path):
 207                     print >> sys.stderr, 'Error: git-checkout-index failed'
 208                     __conflict(path)
 209                     return 1
 210                 if file1_mode != file2_mode:
 211                     print >> sys.stderr, \
 212                           'Error: File "s" added in both, ' \
 213                           'permissions conflict' % path
 214                     __conflict(path)
 215                     return 1
 216             # files are different
 217             else:
 218                 print >> sys.stderr, \
 219                       'Error: File "%s" added in branches but different' % path
 220                 __conflict(path)
 221                 return 1
 222         # file added in one
 223         elif file1_hash or file2_hash:
 224             if file1_hash:
 225                 mode = file1_mode
 226                 obj = file1_hash
 227             else:
 228                 mode = file2_mode
 229                 obj = file2_hash
 230             if os.system('git-update-index --add --cacheinfo %s %s %s'
 231                          % (mode, obj, path)) != 0:
 232                 print >> sys.stderr, 'Error: git-update-index failed'
 233                 __conflict(path)
 234                 return 1
 235             __remove_files(orig_hash, file1_hash, file2_hash)
 236             return os.system('git-checkout-index -u -f -- %s' % path)
 237
 238     # Unhandled case
 239     print >> sys.stderr, 'Error: Unhandled merge conflict: ' \
 240           '"%s" "%s" "%s" "%s" "%s" "%s" "%s"' \
 241           % (orig_hash, file1_hash, file2_hash,
 242              path,
 243              orig_mode, file1_mode, file2_mode)
 244     __conflict(path)
 245     return 1