Introduct git-auto-svn

git_auto_svn.py

Index: git_auto_svn.py
diff --git a/git_auto_svn.py b/git_auto_svn.py
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+#!/usr/bin/env python
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Performs all git-svn setup steps necessary for 'git svn dcommit' to work.
+
+Assumes that trunk of the svn remote maps to master of the git remote.
+
+Example:
+git clone https://chromium.googlesource.com/chromium/tools/depot_tools
+cd depot_tools
+git auto-svn
+"""
+
+import argparse
+import os
+import sys
+import urlparse
+
+import subprocess2
+
+from git_common import run as run_git
+from git_common import run_stream as run_git_stream
+from git_common import set_config, root, ROOT
+from git_footers import parse_footers, get_unique, GIT_SVN_ID_PATTERN
+
+
+SVN_EXE = ROOT+'\\svn.bat' if sys.platform.startswith('win') else 'svn'
+
+
+def run_svn(*cmd, **kwargs):
+  """Runs an svn command.
+
+  Returns (stdout, stderr) as a pair of strings.
+
+  Raises subprocess2.CalledProcessError on nonzero return code.
+  """
+  kwargs.setdefault('stdin', subprocess2.PIPE)
+  kwargs.setdefault('stdout', subprocess2.PIPE)
+  kwargs.setdefault('stderr', subprocess2.PIPE)
+
+  cmd = (SVN_EXE,) + cmd
+  proc = subprocess2.Popen(cmd, **kwargs)
+  ret, err = proc.communicate()
+  retcode = proc.wait()
+  if retcode != 0:
+    raise subprocess2.CalledProcessError(retcode, cmd, os.getcwd(), ret, err)
+
+  return ret, err
+
+
+def main(argv):
+  # No command line flags. Just use the parser to prevent people from trying
+  # to pass flags that don't do anything, and to provide 'usage'.
+  parser = argparse.ArgumentParser(
+      description='Automatically set up git-svn for a repo mirrored from svn.')
+  parser.parse_args(argv[1:])
+
+  upstream = root()
+  message = run_git('log', '-1', '--format=%B', upstream)
+  footers = parse_footers(message)
+  git_svn_id = get_unique(footers, 'git-svn-id')
+  match = GIT_SVN_ID_PATTERN.match(git_svn_id)
+  assert match, 'No valid git-svn-id footer found on %s.' % upstream
+  print 'Found git-svn-id footer %s on %s' % (match.group(1), upstream)
+
+  parsed_svn = urlparse.urlparse(match.group(1))
+  path_components = parsed_svn.path.split('/')
+  svn_repo = None
+  svn_path = None
+  for i in xrange(len(path_components)):
+    try:
+      maybe_repo = '%s://%s%s' % (
+          parsed_svn.scheme, parsed_svn.netloc, '/'.join(path_components[:i+1]))
+      print 'Checking ', maybe_repo
+      run_svn('info', maybe_repo)
+      svn_repo = maybe_repo
+      svn_path = '/'.join(path_components[i+1:])
+      break
+    except subprocess2.CalledProcessError:
+      continue
+  assert svn_repo is not None, 'Unable to find svn repo for %s' % match.group(1)
+  print 'Found upstream svn repo %s and path %s' % (svn_repo, svn_path)
+
+  prefix = upstream.rsplit('/')[0]
+  run_git('svn', 'init', '--prefix=%s' % prefix, '-T', svn_path, svn_repo)
+  set_config('svn-remote.svn.fetch',
+             '%s:refs/remotes/%s' % (svn_path, upstream))
+  print 'Configured metadata, running "git svn fetch". This may take some time.'
+  for line in run_git_stream('svn', 'fetch').xreadlines():
+    print line.strip()
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))