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, out
  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     extensions = file_extensions()
 106
 107     ancestor = filename + extensions['ancestor']
 108     current = filename + extensions['current']
 109     patched = filename + extensions['patched']
 110
 111     if os.path.isfile(ancestor):
 112         three_way = True
 113         files_dict = {'branch1': current,
 114                       'ancestor': ancestor,
 115                       'branch2': patched,
 116                       'output': filename}
 117         imerger = config.get('stgit.i3merge')
 118     else:
 119         three_way = False
 120         files_dict = {'branch1': current,
 121                       'branch2': patched,
 122                       'output': filename}
 123         imerger = config.get('stgit.i2merge')
 124
 125     if not imerger:
 126         raise GitMergeException, 'No interactive merge command configured'
 127
 128     # check whether we have all the files for the merge
 129     for fn in [filename, current, patched]:
 130         if not os.path.isfile(fn):
 131             raise GitMergeException, \
 132                   'Cannot run the interactive merge: "%s" missing' % fn
 133
 134     mtime = os.path.getmtime(filename)
 135
 136     out.info('Trying the interactive %s merge'
 137              % (three_way and 'three-way' or 'two-way'))
 138
 139     err = os.system(imerger % files_dict)
 140     if err != 0:
 141         raise GitMergeException, 'The interactive merge failed: %d' % err
 142     if not os.path.isfile(filename):
 143         raise GitMergeException, 'The "%s" file is missing' % filename
 144     if mtime == os.path.getmtime(filename):
 145         raise GitMergeException, 'The "%s" file was not modified' % filename
 146
 147
 148 #
 149 # Main algorithm
 150 #
 151 def merge(orig_hash, file1_hash, file2_hash,
 152           path,
 153           orig_mode, file1_mode, file2_mode):
 154     """Three-way merge for one file algorithm
 155     """
 156     __checkout_files(orig_hash, file1_hash, file2_hash,
 157                      path,
 158                      orig_mode, file1_mode, file2_mode)
 159
 160     # file exists in origin
 161     if orig_hash:
 162         # modified in both
 163         if file1_hash and file2_hash:
 164             # if modes are the same (git-read-tree probably dealt with it)
 165             if file1_hash == file2_hash:
 166                 if os.system('git-update-index --cacheinfo %s %s %s'
 167                              % (file1_mode, file1_hash, path)) != 0:
 168                     out.error('git-update-index failed')
 169                     __conflict(path)
 170                     return 1
 171                 if os.system('git-checkout-index -u -f -- %s' % path):
 172                     out.error('git-checkout-index failed')
 173                     __conflict(path)
 174                     return 1
 175                 if file1_mode != file2_mode:
 176                     out.error('File added in both, permissions conflict')
 177                     __conflict(path)
 178                     return 1
 179             # 3-way merge
 180             else:
 181                 merge_ok = os.system(str(merger) % {'branch1': src1,
 182                                                     'ancestor': orig,
 183                                                     'branch2': src2,
 184                                                     'output': path }) == 0
 185
 186                 if merge_ok:
 187                     os.system('git-update-index -- %s' % path)
 188                     __remove_files(orig_hash, file1_hash, file2_hash)
 189                     return 0
 190                 else:
 191                     out.error('Three-way merge tool failed for file "%s"'
 192                               % path)
 193                     # reset the cache to the first branch
 194                     os.system('git-update-index --cacheinfo %s %s %s'
 195                               % (file1_mode, file1_hash, path))
 196
 197                     if config.get('stgit.autoimerge') == 'yes':
 198                         try:
 199                             interactive_merge(path)
 200                         except GitMergeException, ex:
 201                             # interactive merge failed
 202                             out.error(ex)
 203                             if str(keeporig) != 'yes':
 204                                 __remove_files(orig_hash, file1_hash,
 205                                                file2_hash)
 206                             __conflict(path)
 207                             return 1
 208                         # successful interactive merge
 209                         os.system('git-update-index -- %s' % path)
 210                         __remove_files(orig_hash, file1_hash, file2_hash)
 211                         return 0
 212                     else:
 213                         # no interactive merge, just mark it as conflict
 214                         if str(keeporig) != 'yes':
 215                             __remove_files(orig_hash, file1_hash, file2_hash)
 216                         __conflict(path)
 217                         return 1
 218
 219         # file deleted in both or deleted in one and unchanged in the other
 220         elif not (file1_hash or file2_hash) \
 221                or file1_hash == orig_hash or file2_hash == orig_hash:
 222             if os.path.exists(path):
 223                 os.remove(path)
 224             __remove_files(orig_hash, file1_hash, file2_hash)
 225             return os.system('git-update-index --remove -- %s' % path)
 226         # file deleted in one and changed in the other
 227         else:
 228             # Do something here - we must at least merge the entry in
 229             # the cache, instead of leaving it in U(nmerged) state. In
 230             # fact, stg resolved does not handle that.
 231
 232             # Do the same thing cogito does - remove the file in any case.
 233             os.system('git-update-index --remove -- %s' % path)
 234
 235             #if file1_hash:
 236                 ## file deleted upstream and changed in the patch. The
 237                 ## patch is probably going to move the changes
 238                 ## elsewhere.
 239
 240                 #os.system('git-update-index --remove -- %s' % path)
 241             #else:
 242                 ## file deleted in the patch and changed upstream. We
 243                 ## could re-delete it, but for now leave it there -
 244                 ## and let the user check if he still wants to remove
 245                 ## the file.
 246
 247                 ## reset the cache to the first branch
 248                 #os.system('git-update-index --cacheinfo %s %s %s'
 249                 #          % (file1_mode, file1_hash, path))
 250             __conflict(path)
 251             return 1
 252
 253     # file does not exist in origin
 254     else:
 255         # file added in both
 256         if file1_hash and file2_hash:
 257             # files are the same
 258             if file1_hash == file2_hash:
 259                 if os.system('git-update-index --add --cacheinfo %s %s %s'
 260                              % (file1_mode, file1_hash, path)) != 0:
 261                     out.error('git-update-index failed')
 262                     __conflict(path)
 263                     return 1
 264                 if os.system('git-checkout-index -u -f -- %s' % path):
 265                     out.error('git-checkout-index failed')
 266                     __conflict(path)
 267                     return 1
 268                 if file1_mode != file2_mode:
 269                     out.error('File "s" added in both, permissions conflict'
 270                               % path)
 271                     __conflict(path)
 272                     return 1
 273             # files added in both but different
 274             else:
 275                 out.error('File "%s" added in branches but different' % path)
 276                 # reset the cache to the first branch
 277                 os.system('git-update-index --cacheinfo %s %s %s'
 278                           % (file1_mode, file1_hash, path))
 279
 280                 if config.get('stgit.autoimerge') == 'yes':
 281                     try:
 282                         interactive_merge(path)
 283                     except GitMergeException, ex:
 284                         # interactive merge failed
 285                         out.error(ex)
 286                         if str(keeporig) != 'yes':
 287                             __remove_files(orig_hash, file1_hash,
 288                                            file2_hash)
 289                         __conflict(path)
 290                         return 1
 291                     # successful interactive merge
 292                     os.system('git-update-index -- %s' % path)
 293                     __remove_files(orig_hash, file1_hash, file2_hash)
 294                     return 0
 295                 else:
 296                     # no interactive merge, just mark it as conflict
 297                     if str(keeporig) != 'yes':
 298                         __remove_files(orig_hash, file1_hash, file2_hash)
 299                     __conflict(path)
 300                     return 1
 301         # file added in one
 302         elif file1_hash or file2_hash:
 303             if file1_hash:
 304                 mode = file1_mode
 305                 obj = file1_hash
 306             else:
 307                 mode = file2_mode
 308                 obj = file2_hash
 309             if os.system('git-update-index --add --cacheinfo %s %s %s'
 310                          % (mode, obj, path)) != 0:
 311                 out.error('git-update-index failed')
 312                 __conflict(path)
 313                 return 1
 314             __remove_files(orig_hash, file1_hash, file2_hash)
 315             return os.system('git-checkout-index -u -f -- %s' % path)
 316
 317     # Unhandled case
 318     out.error('Unhandled merge conflict: "%s" "%s" "%s" "%s" "%s" "%s" "%s"'
 319               % (orig_hash, file1_hash, file2_hash,
 320                  path,
 321                  orig_mode, file1_mode, file2_mode))
 322     __conflict(path)
 323     return 1