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 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 def __remove_files(orig_hash, file1_hash, file2_hash):
  79     """Remove any temporary files
  80     """
  81     if orig_hash:
  82         os.remove(orig)
  83     if file1_hash:
  84         os.remove(src1)
  85     if file2_hash:
  86         os.remove(src2)
  87     pass
  88
  89 def __conflict(path):
  90     """Write the conflict file for the 'path' variable and exit
  91     """
  92     append_string(os.path.join(basedir.get(), 'conflicts'), path)
  93
  94
  95 #
  96 # Main algorithm
  97 #
  98 def merge(orig_hash, file1_hash, file2_hash,
  99           path,
 100           orig_mode, file1_mode, file2_mode):
 101     """Three-way merge for one file algorithm
 102     """
 103     __checkout_files(orig_hash, file1_hash, file2_hash,
 104                      path,
 105                      orig_mode, file1_mode, file2_mode)
 106
 107     # file exists in origin
 108     if orig_hash:
 109         # modified in both
 110         if file1_hash and file2_hash:
 111             # if modes are the same (git-read-tree probably dealt with it)
 112             if file1_hash == file2_hash:
 113                 if os.system('git-update-index --cacheinfo %s %s %s'
 114                              % (file1_mode, file1_hash, path)) != 0:
 115                     print >> sys.stderr, 'Error: git-update-index failed'
 116                     __conflict(path)
 117                     return 1
 118                 if os.system('git-checkout-index -u -f -- %s' % path):
 119                     print >> sys.stderr, 'Error: git-checkout-index failed'
 120                     __conflict(path)
 121                     return 1
 122                 if file1_mode != file2_mode:
 123                     print >> sys.stderr, \
 124                           'Error: File added in both, permissions conflict'
 125                     __conflict(path)
 126                     return 1
 127             # 3-way merge
 128             else:
 129                 merge_ok = os.system(str(merger) % {'branch1': src1,
 130                                                     'ancestor': orig,
 131                                                     'branch2': src2,
 132                                                     'output': path }) == 0
 133
 134                 if merge_ok:
 135                     os.system('git-update-index -- %s' % path)
 136                     __remove_files(orig_hash, file1_hash, file2_hash)
 137                     return 0
 138                 else:
 139                     print >> sys.stderr, \
 140                           'Error: three-way merge tool failed for file "%s"' \
 141                           % path
 142                     # reset the cache to the first branch
 143                     os.system('git-update-index --cacheinfo %s %s %s'
 144                               % (file1_mode, file1_hash, path))
 145                     if str(keeporig) != 'yes':
 146                         __remove_files(orig_hash, file1_hash, file2_hash)
 147                     __conflict(path)
 148                     return 1
 149         # file deleted in both or deleted in one and unchanged in the other
 150         elif not (file1_hash or file2_hash) \
 151                or file1_hash == orig_hash or file2_hash == orig_hash:
 152             if os.path.exists(path):
 153                 os.remove(path)
 154             __remove_files(orig_hash, file1_hash, file2_hash)
 155             return os.system('git-update-index --remove -- %s' % path)
 156         # file deleted in one and changed in the other
 157         else:
 158             # Do something here - we must at least merge the entry in
 159             # the cache, instead of leaving it in U(nmerged) state. In
 160             # fact, stg resolved does not handle that.
 161
 162             # Do the same thing cogito does - remove the file in any case.
 163             os.system('git-update-index --remove -- %s' % path)
 164
 165             #if file1_hash:
 166                 ## file deleted upstream and changed in the patch. The
 167                 ## patch is probably going to move the changes
 168                 ## elsewhere.
 169
 170                 #os.system('git-update-index --remove -- %s' % path)
 171             #else:
 172                 ## file deleted in the patch and changed upstream. We
 173                 ## could re-delete it, but for now leave it there -
 174                 ## and let the user check if he still wants to remove
 175                 ## the file.
 176
 177                 ## reset the cache to the first branch
 178                 #os.system('git-update-index --cacheinfo %s %s %s'
 179                 #          % (file1_mode, file1_hash, path))
 180             __conflict(path)
 181             return 1
 182
 183     # file does not exist in origin
 184     else:
 185         # file added in both
 186         if file1_hash and file2_hash:
 187             # files are the same
 188             if file1_hash == file2_hash:
 189                 if os.system('git-update-index --add --cacheinfo %s %s %s'
 190                              % (file1_mode, file1_hash, path)) != 0:
 191                     print >> sys.stderr, 'Error: git-update-index failed'
 192                     __conflict(path)
 193                     return 1
 194                 if os.system('git-checkout-index -u -f -- %s' % path):
 195                     print >> sys.stderr, 'Error: git-checkout-index failed'
 196                     __conflict(path)
 197                     return 1
 198                 if file1_mode != file2_mode:
 199                     print >> sys.stderr, \
 200                           'Error: File "s" added in both, ' \
 201                           'permissions conflict' % path
 202                     __conflict(path)
 203                     return 1
 204             # files are different
 205             else:
 206                 # reset the index to the current file
 207                 os.system('git-update-index -- %s' % path)
 208                 print >> sys.stderr, \
 209                       'Error: File "%s" added in branches but different' % path
 210                 __conflict(path)
 211                 return 1
 212         # file added in one
 213         elif file1_hash or file2_hash:
 214             if file1_hash:
 215                 mode = file1_mode
 216                 obj = file1_hash
 217             else:
 218                 mode = file2_mode
 219                 obj = file2_hash
 220             if os.system('git-update-index --add --cacheinfo %s %s %s'
 221                          % (mode, obj, path)) != 0:
 222                 print >> sys.stderr, 'Error: git-update-index failed'
 223                 __conflict(path)
 224                 return 1
 225             __remove_files(orig_hash, file1_hash, file2_hash)
 226             return os.system('git-checkout-index -u -f -- %s' % path)
 227
 228     # Unhandled case
 229     print >> sys.stderr, 'Error: Unhandled merge conflict: ' \
 230           '"%s" "%s" "%s" "%s" "%s" "%s" "%s"' \
 231           % (orig_hash, file1_hash, file2_hash,
 232              path,
 233              orig_mode, file1_mode, file2_mode)
 234     __conflict(path)
 235     return 1