1 files changed, 52 insertions, 1 deletions
diff --git a/lorry b/lorry
index 955b46b..c2019d4 100755
--- a/lorry
+++ b/lorry
@@ -31,6 +31,8 @@ import email.message
 import email.utils
 import ftplib
 import re
+import subprocess
+import tempfile
 
 import yaml
 
@@ -621,7 +623,13 @@ class Lorry(cliapp.Application):
         if not os.path.exists(gitdir):
             self.needs_aggressive = True
             self.run_program(['git', 'init', '--bare', gitdir])
-        
+
+        # Since there are marks files in existing deployments that
+        # have broken references, fix up the marks file before rather
+        # than after running hg-fast-export
+        self.prune_unreachable_marks(gitdir,
+                                     os.path.join(gitdir, 'hg2git-marks'))
+
         self.progress('.. fast-exporting into git')
         self.run_program(['hg-fast-export', '-r', '../hg', '--quiet', '--force'],
                          cwd=gitdir)
@@ -718,6 +726,49 @@ class Lorry(cliapp.Application):
         if self.settings['verbose']:
             self.output.write('%s\n' % msg)
 
+    def prune_unreachable_marks(self, gitdir, marks_name):
+        if not os.path.exists(marks_name):
+            return
+
+        # Find reachable commits
+        reachable = set()
+        with subprocess.Popen(['git', 'rev-list', '--all'],
+                              cwd=gitdir, stdin=subprocess.DEVNULL,
+                              stdout=subprocess.PIPE,
+                              universal_newlines=True) as rev_list_proc:
+            for line in rev_list_proc.stdout:
+                reachable.add(line.rstrip('\n'))
+
+        # Filter marks file to temporary file
+        mark_re = re.compile(r':(\S+) ([0-9a-f]{40,})\n')
+        marks_temp_fd, marks_temp_name = \
+            tempfile.mkstemp(dir=os.path.dirname(marks_name))
+        try:
+            with open(marks_temp_fd, 'w') as marks_out, \
+                 open(marks_name, 'r') as marks_in:
+                for line in marks_in:
+                    match = mark_re.match(line)
+                    if not match:
+                        msg = ('%s: failed to parse line "%s"'
+                               % (marks_name, line.rstrip('\n')))
+                        logging.warning(msg)
+                        self.output.write('%s\n' % msg)
+                        # We don't know whether it should be kept; err
+                        # on the side of caution
+                        marks_out.write(line)
+                    elif match.group(2) in reachable:
+                        marks_out.write(line)
+                    else:
+                        self.progress('%s: pruning unreachable commit %s'
+                                      % (marks_name, match.group(2)))
+
+            # On success, replace marks file with temporary file
+            os.rename(marks_temp_name, marks_name)
+        except:
+            # On failure, delete temporary file
+            os.unlink(marks_temp_name)
+            raise
+
 
 if __name__ == '__main__':
     Lorry(version=__version__).run()