X-Git-Url: http://xvm.mit.edu/gitweb/invirt/scripts/git-migration.git/blobdiff_plain/abbc5e9ccf467827545eb44f3603b6bc26bf0a14..f042480e435cbf19bac8bb6ae0d4a16ba57e517f:/git-migrate

diff --git a/git-migrate b/git-migrate
index 65c7a12..f03884f 100755
--- a/git-migrate
+++ b/git-migrate
@@ -5,6 +5,29 @@ import sys
 import subprocess
 import shutil
 
+def tagBase(pkg):
+    p = subprocess.Popen(['git', 'tag',
+                          '-l',
+                          'base'],
+                         cwd='%s.git' % pkg,
+                         stdout=subprocess.PIPE)
+    p.wait()
+    if p.stdout.read().strip() != '':
+        return
+    
+    p = subprocess.Popen(['git', 'rev-list',
+                          '--reverse',
+                          'master'],
+                         cwd='%s.git' % pkg,
+                         stdout=subprocess.PIPE)
+    p.wait()
+    base = p.stdout.read().split()[0]
+    
+    subprocess.check_call(['git', 'tag',
+                           'base',
+                           base],
+                          cwd='%s.git' % pkg)
+
 def clonePackage(base, pkg):
     if not os.path.isdir('%s.git' % pkg):
         if os.path.isdir(pkg):
@@ -27,58 +50,74 @@ def clonePackage(base, pkg):
         
     # Some of these repos have a rev where everything was deleted
     # as a result of the move. We don't want that rev to exist.
-    p = subprocess.Popen(['git', 'ls-files'],
+    p = subprocess.Popen(['git', 'ls-tree', 'HEAD'],
                          cwd='%s.git' % pkg,
                          stdout=subprocess.PIPE)
     p.wait()
     if len(p.stdout.read()) == 0:
         subprocess.check_call(['git', 'reset', '--soft', 'HEAD^'],
                               cwd='%s.git' % pkg)
+    
+    tagBase(pkg)
 
 def cloneAllPackages(base):
     for pkg in open('package-list'):
         clonePackage(base, pkg.strip())
 
 def mergeHistory(old_pkg, new_pkg, n):
-    cwd = os.getcwd()
+    n = int(n)
+    
     subprocess.check_call(['git', 'push',
-                           'file:///%s/%s.git' % (cwd, new_pkg),
+                           '../%s.git' % new_pkg,
                            'master:refs/heads/%s' % old_pkg],
-                          cwd='%s.git' % new_pkg)
-    
-    graft = []
-    p = subprocess.Popen(['git', 'rev-list',
-                          '--reverse',
-                          '--skip=%s' % n,
-                          'master'],
-                         cwd='%s.git' % new_pkg,
-                         stdout=subprocess.PIPE)
-    p.wait()
-    new_rev = p.stdout.read().split()[0]
-    graft.append(new_rev)
+                          cwd='%s.git' % old_pkg)
     
-    # If n isn't 0, then n has a parent commit already that we
-    # shouldn't forget about.
-    if n != 0:
+    # Find the merge commit
+    if n == 0:
         p = subprocess.Popen(['git', 'rev-parse',
-                              '%s^' % new_rev],
+                              'base'],
                              cwd='%s.git' % new_pkg,
                              stdout=subprocess.PIPE)
-        p.wait()
-        graft.append(p.stdout.read().strip())
+    else:
+        p = subprocess.Popen(['git', 'rev-list',
+                              '--reverse',
+                              '--boundary',
+                              '--skip=%s' % (n - 1),
+                              'base..master'],
+                             cwd='%s.git' % new_pkg,
+                             stdout=subprocess.PIPE)
+    p.wait()
+    new_rev = p.stdout.read().split()[0].strip('-')
     
-    # And regardless, the HEAD of old_pkg should be a parent of
-    # new_pkg
+    # Find any other parents of the merge commit
+    p = subprocess.Popen(['git', 'log',
+                          '-1',
+                          '--pretty=format:%P',
+                          new_rev],
+                         cwd='%s.git' % new_pkg,
+                         stdout=subprocess.PIPE)
+    p.wait()
+    parents = p.stdout.read().split()
+    
+    # Find the additional parent we're adding
     p = subprocess.Popen(['git', 'rev-parse',
-                          'master'],
-                         cwd='%s.git' % old_pkg,
+                          old_pkg],
+                         cwd='%s.git' % new_pkg,
                          stdout=subprocess.PIPE)
     p.wait()
-    graft.append(p.stdout.read().strip())
+    parents.append(p.stdout.read().strip())
     
+    # Write out the grafts file
     f = open('%s.git/info/grafts' % new_pkg, 'a')
+    print >>f, '%s %s' % (new_rev, ' '.join(parents))
+    f.close()
     
-    print >>f, ' '.join(graft)
+    # Run filter-branch
+    subprocess.call(['git', 'filter-branch',
+                     '--tag-name-filter', 'cat',
+                     '--',
+                     '--all'],
+                    cwd='%s.git' % new_pkg)
 
 def mergeHistories():
     merges = []
@@ -91,16 +130,6 @@ def mergeHistories():
     
     for merge in merges:
         mergeHistory(*merge)
-    
-    for line in open('package-list'):
-        line = line.strip()
-        subprocess.check_call(['git', 'filter-branch',
-                               '--',
-                               '--all'],
-                              cwd='%s.git' % line)
-    
-    for merge in merges:
-        shutil.rmtree('%s.git' % merge[0])
 
 if __name__ == '__main__':
     try: