git-migrate

   1 #!/usr/bin/python
   2
   3 import os
   4 import sys
   5 import subprocess
   6 import shutil
   7
   8 def clonePackage(base, pkg):
   9     if not os.path.isdir('%s.git' % pkg):
  10         if os.path.isdir(pkg):
  11             shutil.rmtree(pkg)
  12         # Use --no-follow-parent because we're going to handle that with
  13         # grafts.
  14         subprocess.check_call(['git', 'svn', 'clone',
  15                                '--no-follow-parent',
  16                                '-Aauthors',
  17                                '-q',
  18                                '--no-metadata',
  19                                '%s/packages/%s' % (base, pkg)],
  20                               stdout=subprocess.PIPE)
  21
  22         # Then make the repository bare, because git-svn can't do this
  23         shutil.move('%s/.git' % pkg, '%s.git' % pkg)
  24         shutil.rmtree(pkg)
  25         subprocess.check_call(['git', 'config', 'core.bare', 'true'],
  26                               cwd='%s.git' % pkg)
  27
  28     # Some of these repos have a rev where everything was deleted
  29     # as a result of the move. We don't want that rev to exist.
  30     p = subprocess.Popen(['git', 'ls-files'],
  31                          cwd='%s.git' % pkg,
  32                          stdout=subprocess.PIPE)
  33     p.wait()
  34     if len(p.stdout.read()) == 0:
  35         subprocess.check_call(['git', 'reset', 'HEAD^'],
  36                               cwd='%s.git' % pkg)
  37
  38 def cloneAllPackages(base):
  39     for pkg in open('package-list'):
  40         clonePackage(base, pkg.strip())
  41
  42 def mergeHistory(old_pkg, new_pkg, n):
  43     cwd = os.getcwd()
  44     subprocess.check_call(['git', 'push',
  45                            'file:///%s/%s.git' % (cwd, new_pkg),
  46                            'master:refs/heads/%s' % old_pkg],
  47                           cwd='%s.git' % new_pkg)
  48
  49     graft = []
  50     p = subprocess.Popen(['git', 'rev-list',
  51                           '--reverse',
  52                           '--skip=%s' % n,
  53                           'master'],
  54                          cwd='%s.git' % new_pkg,
  55                          stdout=subprocess.PIPE)
  56     p.wait()
  57     new_rev = p.stdout.read().split()[0]
  58     graft.append(new_rev)
  59
  60     # If n isn't 0, then n has a parent commit already that we
  61     # shouldn't forget about.
  62     if n != 0:
  63         p = subprocess.Popen(['git', 'rev-parse',
  64                               '%s^' % new_rev],
  65                              cwd='%s.git' % new_pkg,
  66                              stdout=subprocess.PIPE)
  67         p.wait()
  68         graft.append(p.stdout.read().strip())
  69
  70     # And regardless, the HEAD of old_pkg should be a parent of
  71     # new_pkg
  72     p = subprocess.Popen(['git', 'rev-parse',
  73                           'master'],
  74                          cwd='%s.git' % old_pkg,
  75                          stdout=subprocess.PIPE)
  76     p.wait()
  77     graft.append(p.stdout.read().strip())
  78
  79     f = open('%s.git/info/grafts' % new_pkg, 'a')
  80
  81     print >>f, ' '.join(graft)
  82
  83 def mergeHistories():
  84     grafts = []
  85     for line in open('grafts'):
  86         line = line.strip()
  87         if line[0] == '#' or line == '':
  88             continue
  89
  90         grafts.append(line.split())
  91
  92     for graft in grafts:
  93         mergeHistory(*graft)
  94
  95     for line in open('package-list'):
  96         line = line.strip()
  97         subprocess.check_call(['git', 'filter-branch',
  98                                '--',
  99                                '--all'],
 100                               cwd='%s.git' % line)
 101
 102     for graft in grafts:
 103         shutil.rmtree('%s.git' % graft[0])
 104
 105 if __name__ == '__main__':
 106     try:
 107         base = sys.argv[1]
 108     except:
 109         base = 'svn://invirt.mit.edu/trunk'
 110
 111     cloneAllPackages(base)
 112     mergeHistories()