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, file_extensions, ConfigOption
  24 from stgit.utils import append_string
  25
  26
  27 class GitMergeException(Exception):
  28     pass
  29
  30
  31 #
  32 # Options
  33 #
  34 merger = ConfigOption('stgit', 'merger')
  35 keeporig = ConfigOption('stgit', 'keeporig')
  36
  37 #
  38 # Utility functions
  39 #
  40 def __str2none(x):
  41     if x == '':
  42         return None
  43     else:
  44         return x
  45
  46 def __output(cmd):
  47     f = os.popen(cmd, 'r')
  48     string = f.readline().rstrip()
  49     if f.close():
  50         raise GitMergeException, 'Error: failed to execute "%s"' % cmd
  51     return string
  52
  53 def __checkout_files(orig_hash, file1_hash, file2_hash,
  54                      path,
  55                      orig_mode, file1_mode, file2_mode):
  56     """Check out the files passed as arguments
  57     """
  58     global orig, src1, src2
  59
  60     extensions = file_extensions()
  61
  62     if orig_hash:
  63         orig = path + extensions['ancestor']
  64         tmp = __output('git-unpack-file %s' % orig_hash)
  65         os.chmod(tmp, int(orig_mode, 8))
  66         os.renames(tmp, orig)
  67     if file1_hash:
  68         src1 = path + extensions['current']
  69         tmp = __output('git-unpack-file %s' % file1_hash)
  70         os.chmod(tmp, int(file1_mode, 8))
  71         os.renames(tmp, src1)
  72     if file2_hash:
  73         src2 = path + extensions['patched']
  74         tmp = __output('git-unpack-file %s' % file2_hash)
  75         os.chmod(tmp, int(file2_mode, 8))
  76         os.renames(tmp, src2)
  77
  78     if file1_hash and not os.path.exists(path):
  79         # the current file might be removed by GIT when it is a new
  80         # file added in both branches. Just re-generate it
  81         tmp = __output('git-unpack-file %s' % file1_hash)
  82         os.chmod(tmp, int(file1_mode, 8))
  83         os.renames(tmp, path)
  84
  85 def __remove_files(orig_hash, file1_hash, file2_hash):
  86     """Remove any temporary files
  87     """
  88     if orig_hash:
  89         os.remove(orig)
  90     if file1_hash:
  91         os.remove(src1)
  92     if file2_hash:
  93         os.remove(src2)
  94
  95 def __conflict(path):
  96     """Write the conflict file for the 'path' variable and exit
  97     """
  98     append_string(os.path.join(basedir.get(), 'conflicts'), path)
  99
 100
 101 def interactive_merge(filename):
 102     """Run the interactive merger on the given file. Note that the
 103     index should not have any conflicts.
 104     """
 105     try:
 106         imerger = config.get('stgit', 'imerger')
 107     except Exception, err:
 108         raise GitMergeException, 'Configuration error: %s' % err
 109
 110     extensions = file_extensions()
 111
 112     ancestor = filename + extensions['ancestor']
 113     current = filename + extensions['current']
 114     patched = filename + extensions['patched']
 115
 116     # check whether we have all the files for a three-way merge
 117     for fn in [filename, ancestor, current, patched]:
 118         if not os.path.isfile(fn):
 119             raise GitMergeException, \
 120                   'Cannot run the interactive merger: "%s" missing' % fn
 121
 122     mtime = os.path.getmtime(filename)
 123
 124     err = os.system(imerger % {'branch1': current,
 125                                'ancestor': ancestor,
 126                                'branch2': patched,
 127                                'output': filename})
 128
 129     if err != 0:
 130         raise GitMergeException, 'The interactive merge failed: %d' % err
 131     if not os.path.isfile(filename):
 132         raise GitMergeException, 'The "%s" file is missing' % filename
 133     if mtime == os.path.getmtime(filename):
 134         raise GitMergeException, 'The "%s" file was not modified' % filename
 135
 136
 137 #
 138 # Main algorithm
 139 #
 140 def merge(orig_hash, file1_hash, file2_hash,
 141           path,
 142           orig_mode, file1_mode, file2_mode):
 143     """Three-way merge for one file algorithm
 144     """
 145     __checkout_files(orig_hash, file1_hash, file2_hash,
 146                      path,
 147                      orig_mode, file1_mode, file2_mode)
 148
 149     # file exists in origin
 150     if orig_hash:
 151         # modified in both
 152         if file1_hash and file2_hash:
 153             # if modes are the same (git-read-tree probably dealt with it)
 154             if file1_hash == file2_hash:
 155                 if os.system('git-update-index --cacheinfo %s %s %s'
 156                              % (file1_mode, file1_hash, path)) != 0:
 157                     print >> sys.stderr, 'Error: git-update-index failed'
 158                     __conflict(path)
 159                     return 1
 160                 if os.system('git-checkout-index -u -f -- %s' % path):
 161                     print >> sys.stderr, 'Error: git-checkout-index failed'
 162                     __conflict(path)
 163                     return 1
 164                 if file1_mode != file2_mode:
 165                     print >> sys.stderr, \
 166                           'Error: File added in both, permissions conflict'
 167                     __conflict(path)
 168                     return 1
 169             # 3-way merge
 170             else:
 171                 merge_ok = os.system(str(merger) % {'branch1': src1,
 172                                                     'ancestor': orig,
 173                                                     'branch2': src2,
 174                                                     'output': path }) == 0
 175
 176                 if merge_ok:
 177                     os.system('git-update-index -- %s' % path)
 178                     __remove_files(orig_hash, file1_hash, file2_hash)
 179                     return 0
 180                 else:
 181                     print >> sys.stderr, \
 182                           'Error: three-way merge tool failed for file "%s"' \
 183                           % path
 184                     # reset the cache to the first branch
 185                     os.system('git-update-index --cacheinfo %s %s %s'
 186                               % (file1_mode, file1_hash, path))
 187
 188                     if config.get('stgit', 'autoimerge') == 'yes':
 189                         print >> sys.stderr, \
 190                               'Trying the interactive merge'
 191                         try:
 192                             interactive_merge(path)
 193                         except GitMergeException, ex:
 194                             # interactive merge failed
 195                             print >> sys.stderr, str(ex)
 196                             if str(keeporig) != 'yes':
 197                                 __remove_files(orig_hash, file1_hash,
 198                                                file2_hash)
 199                             __conflict(path)
 200                             return 1
 201                         # successful interactive merge
 202                         os.system('git-update-index -- %s' % path)
 203                         __remove_files(orig_hash, file1_hash, file2_hash)
 204                         return 0
 205                     else:
 206                         # no interactive merge, just mark it as conflict
 207                         if str(keeporig) != 'yes':
 208                             __remove_files(orig_hash, file1_hash, file2_hash)
 209                         __conflict(path)
 210                         return 1
 211
 212         # file deleted in both or deleted in one and unchanged in the other
 213         elif not (file1_hash or file2_hash) \
 214                or file1_hash == orig_hash or file2_hash == orig_hash:
 215             if os.path.exists(path):
 216                 os.remove(path)
 217             __remove_files(orig_hash, file1_hash, file2_hash)
 218             return os.system('git-update-index --remove -- %s' % path)
 219         # file deleted in one and changed in the other
 220         else:
 221             # Do something here - we must at least merge the entry in
 222             # the cache, instead of leaving it in U(nmerged) state. In
 223             # fact, stg resolved does not handle that.
 224
 225             # Do the same thing cogito does - remove the file in any case.
 226             os.system('git-update-index --remove -- %s' % path)
 227
 228             #if file1_hash:
 229                 ## file deleted upstream and changed in the patch. The
 230                 ## patch is probably going to move the changes
 231                 ## elsewhere.
 232
 233                 #os.system('git-update-index --remove -- %s' % path)
 234             #else:
 235                 ## file deleted in the patch and changed upstream. We
 236                 ## could re-delete it, but for now leave it there -
 237                 ## and let the user check if he still wants to remove
 238                 ## the file.
 239
 240                 ## reset the cache to the first branch
 241                 #os.system('git-update-index --cacheinfo %s %s %s'
 242                 #          % (file1_mode, file1_hash, path))
 243             __conflict(path)
 244             return 1
 245
 246     # file does not exist in origin
 247     else:
 248         # file added in both
 249         if file1_hash and file2_hash:
 250             # files are the same
 251             if file1_hash == file2_hash:
 252                 if os.system('git-update-index --add --cacheinfo %s %s %s'
 253                              % (file1_mode, file1_hash, path)) != 0:
 254                     print >> sys.stderr, 'Error: git-update-index failed'
 255                     __conflict(path)
 256                     return 1
 257                 if os.system('git-checkout-index -u -f -- %s' % path):
 258                     print >> sys.stderr, 'Error: git-checkout-index failed'
 259                     __conflict(path)
 260                     return 1
 261                 if file1_mode != file2_mode:
 262                     print >> sys.stderr, \
 263                           'Error: File "s" added in both, ' \
 264                           'permissions conflict' % path
 265                     __conflict(path)
 266                     return 1
 267             # files are different
 268             else:
 269                 # reset the index to the current file
 270                 os.system('git-update-index -- %s' % path)
 271                 print >> sys.stderr, \
 272                       'Error: File "%s" added in branches but different' % path
 273                 __conflict(path)
 274                 return 1
 275         # file added in one
 276         elif file1_hash or file2_hash:
 277             if file1_hash:
 278                 mode = file1_mode
 279                 obj = file1_hash
 280             else:
 281                 mode = file2_mode
 282                 obj = file2_hash
 283             if os.system('git-update-index --add --cacheinfo %s %s %s'
 284                          % (mode, obj, path)) != 0:
 285                 print >> sys.stderr, 'Error: git-update-index failed'
 286                 __conflict(path)
 287                 return 1
 288             __remove_files(orig_hash, file1_hash, file2_hash)
 289             return os.system('git-checkout-index -u -f -- %s' % path)
 290
 291     # Unhandled case
 292     print >> sys.stderr, 'Error: Unhandled merge conflict: ' \
 293           '"%s" "%s" "%s" "%s" "%s" "%s" "%s"' \
 294           % (orig_hash, file1_hash, file2_hash,
 295              path,
 296              orig_mode, file1_mode, file2_mode)
 297     __conflict(path)
 298     return 1