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 import basedir
  23 from stgit.config import config
  24 from stgit.utils import append_string
  25
  26
  27 class GitMergeException(Exception):
  28     pass
  29
  30
  31 #
  32 # Options
  33 #
  34 try:
  35     merger = config.get('stgit', 'merger')
  36     keeporig = config.get('stgit', 'keeporig')
  37 except Exception, err:
  38     raise GitMergeException, 'Configuration error: %s' % err
  39
  40
  41 #
  42 # Utility functions
  43 #
  44 def __str2none(x):
  45     if x == '':
  46         return None
  47     else:
  48         return x
  49
  50 def __output(cmd):
  51     f = os.popen(cmd, 'r')
  52     string = f.readline().rstrip()
  53     if f.close():
  54         raise GitMergeException, 'Error: failed to execute "%s"' % cmd
  55     return string
  56
  57 def __checkout_files(orig_hash, file1_hash, file2_hash,
  58                      path,
  59                      orig_mode, file1_mode, file2_mode):
  60     """Check out the files passed as arguments
  61     """
  62     global orig, src1, src2
  63
  64     if orig_hash:
  65         orig = '%s.older' % path
  66         tmp = __output('git-unpack-file %s' % orig_hash)
  67         os.chmod(tmp, int(orig_mode, 8))
  68         os.renames(tmp, orig)
  69     if file1_hash:
  70         src1 = '%s.local' % path
  71         tmp = __output('git-unpack-file %s' % file1_hash)
  72         os.chmod(tmp, int(file1_mode, 8))
  73         os.renames(tmp, src1)
  74     if file2_hash:
  75         src2 = '%s.remote' % path
  76         tmp = __output('git-unpack-file %s' % file2_hash)
  77         os.chmod(tmp, int(file2_mode, 8))
  78         os.renames(tmp, src2)
  79
  80 def __remove_files(orig_hash, file1_hash, file2_hash):
  81     """Remove any temporary files
  82     """
  83     if orig_hash:
  84         os.remove(orig)
  85     if file1_hash:
  86         os.remove(src1)
  87     if file2_hash:
  88         os.remove(src2)
  89     pass
  90
  91 def __conflict(path):
  92     """Write the conflict file for the 'path' variable and exit
  93     """
  94     append_string(os.path.join(basedir.get(), 'conflicts'), path)
  95
  96
  97 #
  98 # Main algorithm
  99 #
 100 def merge(orig_hash, file1_hash, file2_hash,
 101           path,
 102           orig_mode, file1_mode, file2_mode):
 103     """Three-way merge for one file algorithm
 104     """
 105     __checkout_files(orig_hash, file1_hash, file2_hash,
 106                      path,
 107                      orig_mode, file1_mode, file2_mode)
 108
 109     # file exists in origin
 110     if orig_hash:
 111         # modified in both
 112         if file1_hash and file2_hash:
 113             # if modes are the same (git-read-tree probably dealt with it)
 114             if file1_hash == file2_hash:
 115                 if os.system('git-update-index --cacheinfo %s %s %s'
 116                              % (file1_mode, file1_hash, path)) != 0:
 117                     print >> sys.stderr, 'Error: git-update-index failed'
 118                     __conflict(path)
 119                     return 1
 120                 if os.system('git-checkout-index -u -f -- %s' % path):
 121                     print >> sys.stderr, 'Error: git-checkout-index failed'
 122                     __conflict(path)
 123                     return 1
 124                 if file1_mode != file2_mode:
 125                     print >> sys.stderr, \
 126                           'Error: File added in both, permissions conflict'
 127                     __conflict(path)
 128                     return 1
 129             # 3-way merge
 130             else:
 131                 merge_ok = os.system(merger % {'branch1': src1,
 132                                                'ancestor': orig,
 133                                                'branch2': src2,
 134                                                'output': path }) == 0
 135
 136                 if merge_ok:
 137                     os.system('git-update-index -- %s' % path)
 138                     __remove_files(orig_hash, file1_hash, file2_hash)
 139                     return 0
 140                 else:
 141                     print >> sys.stderr, \
 142                           'Error: three-way merge tool failed for file "%s"' \
 143                           % path
 144                     # reset the cache to the first branch
 145                     os.system('git-update-index --cacheinfo %s %s %s'
 146                               % (file1_mode, file1_hash, path))
 147                     if keeporig != 'yes':
 148                         __remove_files(orig_hash, file1_hash, file2_hash)
 149                     __conflict(path)
 150                     return 1
 151         # file deleted in both or deleted in one and unchanged in the other
 152         elif not (file1_hash or file2_hash) \
 153                or file1_hash == orig_hash or file2_hash == orig_hash:
 154             if os.path.exists(path):
 155                 os.remove(path)
 156             __remove_files(orig_hash, file1_hash, file2_hash)
 157             return os.system('git-update-index --remove -- %s' % path)
 158         # file deleted in one and changed in the other
 159         else:
 160             # Do something here - we must at least merge the entry in
 161             # the cache, instead of leaving it in U(nmerged) state. In
 162             # fact, stg resolved does not handle that.
 163
 164             # Do the same thing cogito does - remove the file in any case.
 165             os.system('git-update-index --remove -- %s' % path)
 166
 167             #if file1_hash:
 168                 ## file deleted upstream and changed in the patch. The
 169                 ## patch is probably going to move the changes
 170                 ## elsewhere.
 171
 172                 #os.system('git-update-index --remove -- %s' % path)
 173             #else:
 174                 ## file deleted in the patch and changed upstream. We
 175                 ## could re-delete it, but for now leave it there -
 176                 ## and let the user check if he still wants to remove
 177                 ## the file.
 178
 179                 ## reset the cache to the first branch
 180                 #os.system('git-update-index --cacheinfo %s %s %s'
 181                 #          % (file1_mode, file1_hash, path))
 182             __conflict(path)
 183             return 1
 184
 185     # file does not exist in origin
 186     else:
 187         # file added in both
 188         if file1_hash and file2_hash:
 189             # files are the same
 190             if file1_hash == file2_hash:
 191                 if os.system('git-update-index --add --cacheinfo %s %s %s'
 192                              % (file1_mode, file1_hash, path)) != 0:
 193                     print >> sys.stderr, 'Error: git-update-index failed'
 194                     __conflict(path)
 195                     return 1
 196                 if os.system('git-checkout-index -u -f -- %s' % path):
 197                     print >> sys.stderr, 'Error: git-checkout-index failed'
 198                     __conflict(path)
 199                     return 1
 200                 if file1_mode != file2_mode:
 201                     print >> sys.stderr, \
 202                           'Error: File "s" added in both, ' \
 203                           'permissions conflict' % path
 204                     __conflict(path)
 205                     return 1
 206             # files are different
 207             else:
 208                 # reset the index to the current file
 209                 os.system('git-update-index -- %s' % path)
 210                 print >> sys.stderr, \
 211                       'Error: File "%s" added in branches but different' % path
 212                 __conflict(path)
 213                 return 1
 214         # file added in one
 215         elif file1_hash or file2_hash:
 216             if file1_hash:
 217                 mode = file1_mode
 218                 obj = file1_hash
 219             else:
 220                 mode = file2_mode
 221                 obj = file2_hash
 222             if os.system('git-update-index --add --cacheinfo %s %s %s'
 223                          % (mode, obj, path)) != 0:
 224                 print >> sys.stderr, 'Error: git-update-index failed'
 225                 __conflict(path)
 226                 return 1
 227             __remove_files(orig_hash, file1_hash, file2_hash)
 228             return os.system('git-checkout-index -u -f -- %s' % path)
 229
 230     # Unhandled case
 231     print >> sys.stderr, 'Error: Unhandled merge conflict: ' \
 232           '"%s" "%s" "%s" "%s" "%s" "%s" "%s"' \
 233           % (orig_hash, file1_hash, file2_hash,
 234              path,
 235              orig_mode, file1_mode, file2_mode)
 236     __conflict(path)
 237     return 1