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