diff --git a/.pylintrc b/.pylintrc
index 9f81ee1..9e8882e 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -53,7 +53,7 @@
 enable=RP0004
 
 # Disable the message(s) with the given id(s).
-disable=R0903,R0912,R0913,R0914,R0915,W0141,C0111,C0103,C0323,C0322,C0324,W0603,W0703,R0911,C0301,C0302,R0902,R0904,W0142,W0212,E1101,E1103,R0201,W0201,W0122,W0232,W0311,RP0001,RP0003,RP0101,RP0002,RP0401,RP0701,RP0801
+disable=R0903,R0912,R0913,R0914,R0915,W0141,C0111,C0103,W0603,W0703,R0911,C0301,C0302,R0902,R0904,W0142,W0212,E1101,E1103,R0201,W0201,W0122,W0232,RP0001,RP0003,RP0101,RP0002,RP0401,RP0701,RP0801
 
 [REPORTS]
 
diff --git a/color.py b/color.py
index 9200a29..d856313 100644
--- a/color.py
+++ b/color.py
@@ -36,50 +36,51 @@
          'blink'  : 5,
          'reverse': 7}
 
-RESET = "\033[m"
+RESET = "\033[m"  # pylint: disable=W1401
+                  # backslash is not anomalous
 
 def is_color(s):
-    return s in COLORS
+  return s in COLORS
 
 def is_attr(s):
-    return s in ATTRS
+  return s in ATTRS
 
 def _Color(fg = None, bg = None, attr = None):
-    fg = COLORS[fg]
-    bg = COLORS[bg]
-    attr = ATTRS[attr]
+  fg = COLORS[fg]
+  bg = COLORS[bg]
+  attr = ATTRS[attr]
 
-    if attr >= 0 or fg >= 0 or bg >= 0:
-      need_sep = False
-      code = "\033["
+  if attr >= 0 or fg >= 0 or bg >= 0:
+    need_sep = False
+    code = "\033["  #pylint: disable=W1401
 
-      if attr >= 0:
-        code += chr(ord('0') + attr)
-        need_sep = True
+    if attr >= 0:
+      code += chr(ord('0') + attr)
+      need_sep = True
 
-      if fg >= 0:
-        if need_sep:
-          code += ';'
-        need_sep = True
+    if fg >= 0:
+      if need_sep:
+        code += ';'
+      need_sep = True
 
-        if fg < 8:
-          code += '3%c' % (ord('0') + fg)
-        else:
-          code += '38;5;%d' % fg
+      if fg < 8:
+        code += '3%c' % (ord('0') + fg)
+      else:
+        code += '38;5;%d' % fg
 
-      if bg >= 0:
-        if need_sep:
-          code += ';'
-        need_sep = True
+    if bg >= 0:
+      if need_sep:
+        code += ';'
+      need_sep = True
 
-        if bg < 8:
-          code += '4%c' % (ord('0') + bg)
-        else:
-          code += '48;5;%d' % bg
-      code += 'm'
-    else:
-      code = ''
-    return code
+      if bg < 8:
+        code += '4%c' % (ord('0') + bg)
+      else:
+        code += '48;5;%d' % bg
+    code += 'm'
+  else:
+    code = ''
+  return code
 
 
 class Coloring(object):
diff --git a/command.py b/command.py
index 0c3b360..96d7848 100644
--- a/command.py
+++ b/command.py
@@ -22,6 +22,7 @@
 from error import NoSuchProjectError
 from error import InvalidProjectGroupsError
 
+
 class Command(object):
   """Base class for any command line action in repo.
   """
@@ -33,6 +34,27 @@
   def WantPager(self, opt):
     return False
 
+  def ReadEnvironmentOptions(self, opts):
+    """ Set options from environment variables. """
+
+    env_options = self._RegisteredEnvironmentOptions()
+
+    for env_key, opt_key in env_options.items():
+      # Get the user-set option value if any
+      opt_value = getattr(opts, opt_key)
+
+      # If the value is set, it means the user has passed it as a command
+      # line option, and we should use that.  Otherwise we can try to set it
+      # with the value from the corresponding environment variable.
+      if opt_value is not None:
+        continue
+
+      env_value = os.environ.get(env_key)
+      if env_value is not None:
+        setattr(opts, opt_key, env_value)
+
+    return opts
+
   @property
   def OptionParser(self):
     if self._optparse is None:
@@ -49,6 +71,24 @@
     """Initialize the option parser.
     """
 
+  def _RegisteredEnvironmentOptions(self):
+    """Get options that can be set from environment variables.
+
+    Return a dictionary mapping environment variable name
+    to option key name that it can override.
+
+    Example: {'REPO_MY_OPTION': 'my_option'}
+
+    Will allow the option with key value 'my_option' to be set
+    from the value in the environment variable named 'REPO_MY_OPTION'.
+
+    Note: This does not work properly for options that are explicitly
+    set to None by the user, or options that are defined with a
+    default value other than None.
+
+    """
+    return {}
+
   def Usage(self):
     """Display usage and terminate.
     """
@@ -60,7 +100,33 @@
     """
     raise NotImplementedError
 
-  def GetProjects(self, args, missing_ok=False):
+  def _ResetPathToProjectMap(self, projects):
+    self._by_path = dict((p.worktree, p) for p in projects)
+
+  def _UpdatePathToProjectMap(self, project):
+    self._by_path[project.worktree] = project
+
+  def _GetProjectByPath(self, path):
+    project = None
+    if os.path.exists(path):
+      oldpath = None
+      while path \
+        and path != oldpath \
+        and path != self.manifest.topdir:
+        try:
+          project = self._by_path[path]
+          break
+        except KeyError:
+          oldpath = path
+          path = os.path.dirname(path)
+    else:
+      try:
+        project = self._by_path[path]
+      except KeyError:
+        pass
+    return project
+
+  def GetProjects(self, args, missing_ok=False, submodules_ok=False):
     """A list of projects that match the arguments.
     """
     all_projects = self.manifest.projects
@@ -71,43 +137,40 @@
     groups = mp.config.GetString('manifest.groups')
     if not groups:
       groups = 'all,-notdefault,platform-' + platform.system().lower()
-    groups = [x for x in re.split('[,\s]+', groups) if x]
+    groups = [x for x in re.split(r'[,\s]+', groups) if x]
 
     if not args:
-      for project in all_projects.values():
+      all_projects_list = all_projects.values()
+      derived_projects = {}
+      for project in all_projects_list:
+        if submodules_ok or project.sync_s:
+          derived_projects.update((p.name, p)
+                                  for p in project.GetDerivedSubprojects())
+      all_projects_list.extend(derived_projects.values())
+      for project in all_projects_list:
         if ((missing_ok or project.Exists) and
             project.MatchesGroups(groups)):
           result.append(project)
     else:
-      by_path = None
+      self._ResetPathToProjectMap(all_projects.values())
 
       for arg in args:
         project = all_projects.get(arg)
 
         if not project:
           path = os.path.abspath(arg).replace('\\', '/')
+          project = self._GetProjectByPath(path)
 
-          if not by_path:
-            by_path = dict()
-            for p in all_projects.values():
-              by_path[p.worktree] = p
-
-          if os.path.exists(path):
-            oldpath = None
-            while path \
-              and path != oldpath \
-              and path != self.manifest.topdir:
-              try:
-                project = by_path[path]
-                break
-              except KeyError:
-                oldpath = path
-                path = os.path.dirname(path)
-          else:
-            try:
-              project = by_path[path]
-            except KeyError:
-              pass
+          # If it's not a derived project, update path->project mapping and
+          # search again, as arg might actually point to a derived subproject.
+          if (project and not project.Derived and
+              (submodules_ok or project.sync_s)):
+            search_again = False
+            for subproject in project.GetDerivedSubprojects():
+              self._UpdatePathToProjectMap(subproject)
+              search_again = True
+            if search_again:
+              project = self._GetProjectByPath(path) or project
 
         if not project:
           raise NoSuchProjectError(arg)
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index f499868..0bf09f6 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -41,17 +41,21 @@
     <!ATTLIST default revision CDATA #IMPLIED>
     <!ATTLIST default sync-j   CDATA #IMPLIED>
     <!ATTLIST default sync-c   CDATA #IMPLIED>
+    <!ATTLIST default sync-s   CDATA #IMPLIED>
 
     <!ELEMENT manifest-server (EMPTY)>
     <!ATTLIST url              CDATA #REQUIRED>
   
-    <!ELEMENT project (annotation?)>
+    <!ELEMENT project (annotation?,
+                       project*)>
     <!ATTLIST project name     CDATA #REQUIRED>
     <!ATTLIST project path     CDATA #IMPLIED>
     <!ATTLIST project remote   IDREF #IMPLIED>
     <!ATTLIST project revision CDATA #IMPLIED>
     <!ATTLIST project groups   CDATA #IMPLIED>
     <!ATTLIST project sync-c   CDATA #IMPLIED>
+    <!ATTLIST project sync-s   CDATA #IMPLIED>
+    <!ATTLIST project upstream CDATA #IMPLIED>
 
     <!ELEMENT annotation (EMPTY)>
     <!ATTLIST annotation name  CDATA #REQUIRED>
@@ -119,6 +123,15 @@
 `refs/heads/master`).  Project elements lacking their own
 revision attribute will use this revision.
 
+Attribute `sync_j`: Number of parallel jobs to use when synching.
+
+Attribute `sync_c`: Set to true to only sync the given Git
+branch (specified in the `revision` attribute) rather than the
+whole ref space.  Project elements lacking a sync_c element of
+their own will use this value.
+
+Attribute `sync_s`: Set to true to also sync sub-projects.
+
 
 Element manifest-server
 -----------------------
@@ -152,7 +165,10 @@
 
 One or more project elements may be specified.  Each element
 describes a single Git repository to be cloned into the repo
-client workspace.
+client workspace.  You may specify Git-submodules by creating a
+nested project.  Git-submodules will be automatically
+recognized and inherit their parent's attributes, but those
+may be overridden by an explicitly specified project element.
 
 Attribute `name`: A unique name for this project.  The project's
 name is appended onto its remote's fetch URL to generate the actual
@@ -163,7 +179,8 @@
 where ${remote_fetch} is the remote's fetch attribute and
 ${project_name} is the project's name attribute.  The suffix ".git"
 is always appended as repo assumes the upstream is a forest of
-bare Git repositories.
+bare Git repositories.  If the project has a parent element, its
+name will be prefixed by the parent's.
 
 The project name must match the name Gerrit knows, if Gerrit is
 being used for code reviews.
@@ -171,6 +188,8 @@
 Attribute `path`: An optional path relative to the top directory
 of the repo client where the Git working directory for this project
 should be placed.  If not supplied the project name is used.
+If the project has a parent element, its path will be prefixed
+by the parent's.
 
 Attribute `remote`: Name of a previously defined remote element.
 If not supplied the remote given by the default element is used.
@@ -190,6 +209,18 @@
 definition is implicitly in the following manifest groups:
 default, name:monkeys, and path:barrel-of.  If you place a project in the
 group "notdefault", it will not be automatically downloaded by repo.
+If the project has a parent element, the `name` and `path` here
+are the prefixed ones.
+
+Attribute `sync_c`: Set to true to only sync the given Git
+branch (specified in the `revision` attribute) rather than the
+whole ref space.
+
+Attribute `sync_s`: Set to true to also sync sub-projects.
+
+Attribute `upstream`: Name of the Git branch in which a sha1
+can be found.  Used when syncing a revision locked manifest in
+-c mode to avoid having to sync the entire ref space.
 
 Element annotation
 ------------------
@@ -209,7 +240,7 @@
 allowing a subsequent project element in the same manifest file to
 replace the project with a different source.
 
-This element is mostly useful in the local_manifest.xml, where
+This element is mostly useful in a local manifest file, where
 the user can remove a project, and possibly replace it with their
 own definition.
 
@@ -218,21 +249,25 @@
 
 This element provides the capability of including another manifest
 file into the originating manifest.  Normal rules apply for the
-target manifest to include- it must be a usable manifest on it's own.
+target manifest to include - it must be a usable manifest on its own.
 
-Attribute `name`; the manifest to include, specified relative to
-the manifest repositories root.
+Attribute `name`: the manifest to include, specified relative to
+the manifest repository's root.
 
 
-Local Manifest
-==============
+Local Manifests
+===============
 
-Additional remotes and projects may be added through a local
-manifest, stored in `$TOP_DIR/.repo/local_manifest.xml`.
+Additional remotes and projects may be added through local manifest
+files stored in `$TOP_DIR/.repo/local_manifests/*.xml`.
 
 For example:
 
-  $ cat .repo/local_manifest.xml
+  $ ls .repo/local_manifests
+  local_manifest.xml
+  another_local_manifest.xml
+
+  $ cat .repo/local_manifests/local_manifest.xml
   <?xml version="1.0" encoding="UTF-8"?>
   <manifest>
     <project path="manifest"
@@ -241,6 +276,17 @@
              name="platform/manifest" />
   </manifest>
 
-Users may add projects to the local manifest prior to a `repo sync`
+Users may add projects to the local manifest(s) prior to a `repo sync`
 invocation, instructing repo to automatically download and manage
 these extra projects.
+
+Manifest files stored in `$TOP_DIR/.repo/local_manifests/*.xml` will
+be loaded in alphabetical order.
+
+Additional remotes and projects may also be added through a local
+manifest, stored in `$TOP_DIR/.repo/local_manifest.xml`. This method
+is deprecated in favor of using multiple manifest files as mentioned
+above.
+
+If `$TOP_DIR/.repo/local_manifest.xml` exists, it will be loaded before
+any manifest files stored in `$TOP_DIR/.repo/local_manifests/*.xml`.
diff --git a/editor.py b/editor.py
index 489c6cd..883a1a8 100644
--- a/editor.py
+++ b/editor.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import re
 import sys
@@ -53,10 +54,10 @@
       return e
 
     if os.getenv('TERM') == 'dumb':
-      print >>sys.stderr,\
+      print(
 """No editor specified in GIT_EDITOR, core.editor, VISUAL or EDITOR.
 Tried to fall back to vi but terminal is dumb.  Please configure at
-least one of these before using this command."""
+least one of these before using this command.""", file=sys.stderr)
       sys.exit(1)
 
     return 'vi'
@@ -67,7 +68,7 @@
 
        Args:
          data        : the text to edit
-  
+
       Returns:
         new value of edited text; None if editing did not succeed
     """
diff --git a/error.py b/error.py
index 2148248..7e52b01 100644
--- a/error.py
+++ b/error.py
@@ -21,6 +21,10 @@
   """The revision value in a project is incorrect.
   """
 
+class NoManifestException(Exception):
+  """The required manifest does not exist.
+  """
+
 class EditorError(Exception):
   """Unspecified error from the user's text editor.
   """
diff --git a/git_command.py b/git_command.py
index a40e6c0..d347dd6 100644
--- a/git_command.py
+++ b/git_command.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import sys
 import subprocess
@@ -88,11 +89,11 @@
       ver_str = git.version()
       if ver_str.startswith('git version '):
         _git_version = tuple(
-          map(lambda x: int(x),
+          map(int,
             ver_str[len('git version '):].strip().split('-')[0].split('.')[0:3]
           ))
       else:
-        print >>sys.stderr, 'fatal: "%s" unsupported' % ver_str
+        print('fatal: "%s" unsupported' % ver_str, file=sys.stderr)
         sys.exit(1)
     return _git_version
 
@@ -110,8 +111,8 @@
   if min_version <= git_version:
     return True
   if fail:
-    need = '.'.join(map(lambda x: str(x), min_version))
-    print >>sys.stderr, 'fatal: git %s or later required' % need
+    need = '.'.join(map(str, min_version))
+    print('fatal: git %s or later required' % need, file=sys.stderr)
     sys.exit(1)
   return False
 
@@ -132,15 +133,15 @@
                gitdir = None):
     env = os.environ.copy()
 
-    for e in [REPO_TRACE,
+    for key in [REPO_TRACE,
               GIT_DIR,
               'GIT_ALTERNATE_OBJECT_DIRECTORIES',
               'GIT_OBJECT_DIRECTORY',
               'GIT_WORK_TREE',
               'GIT_GRAFT_FILE',
               'GIT_INDEX_FILE']:
-      if e in env:
-        del env[e]
+      if key in env:
+        del env[key]
 
     if disable_editor:
       _setenv(env, 'GIT_EDITOR', ':')
diff --git a/git_config.py b/git_config.py
index ae28855..56cc6a2 100644
--- a/git_config.py
+++ b/git_config.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import cPickle
 import os
 import re
@@ -23,7 +24,18 @@
 except ImportError:
   import dummy_threading as _threading
 import time
-import urllib2
+try:
+  import urllib2
+except ImportError:
+  # For python3
+  import urllib.request
+  import urllib.error
+else:
+  # For python2
+  import imp
+  urllib = imp.new_module('urllib')
+  urllib.request = urllib2
+  urllib.error = urllib2
 
 from signal import SIGTERM
 from error import GitError, UploadError
@@ -35,7 +47,7 @@
 
 R_HEADS = 'refs/heads/'
 R_TAGS  = 'refs/tags/'
-ID_RE = re.compile('^[0-9a-f]{40}$')
+ID_RE = re.compile(r'^[0-9a-f]{40}$')
 
 REVIEW_CACHE = dict()
 
@@ -157,7 +169,7 @@
       elif old != value:
         self._cache[key] = list(value)
         self._do('--replace-all', name, value[0])
-        for i in xrange(1, len(value)):
+        for i in range(1, len(value)):
           self._do('--add', name, value[i])
 
     elif len(old) != 1 or old[0] != value:
@@ -288,12 +300,13 @@
     d = self._do('--null', '--list')
     if d is None:
       return c
-    for line in d.rstrip('\0').split('\0'):
+    for line in d.rstrip('\0').split('\0'):  # pylint: disable=W1401
+                                             # Backslash is not anomalous
       if '\n' in line:
-          key, val = line.split('\n', 1)
+        key, val = line.split('\n', 1)
       else:
-          key = line
-          val = None
+        key = line
+        val = None
 
       if key in c:
         c[key].append(val)
@@ -418,7 +431,7 @@
                      '-o','ControlPath %s' % ssh_sock(),
                      host]
     if port is not None:
-      command_base[1:1] = ['-p',str(port)]
+      command_base[1:1] = ['-p', str(port)]
 
     # Since the key wasn't in _master_keys, we think that master isn't running.
     # ...but before actually starting a master, we'll double-check.  This can
@@ -451,9 +464,8 @@
       p = subprocess.Popen(command)
     except Exception as e:
       _ssh_master = False
-      print >>sys.stderr, \
-        '\nwarn: cannot enable ssh control master for %s:%s\n%s' \
-        % (host,port, str(e))
+      print('\nwarn: cannot enable ssh control master for %s:%s\n%s'
+             % (host,port, str(e)), file=sys.stderr)
       return False
 
     _master_processes.append(p)
@@ -525,7 +537,7 @@
     self.url = self._Get('url')
     self.review = self._Get('review')
     self.projectname = self._Get('projectname')
-    self.fetch = map(lambda x: RefSpec.FromString(x),
+    self.fetch = map(RefSpec.FromString,
                      self._Get('fetch', all_keys=True))
     self._review_url = None
 
@@ -579,7 +591,7 @@
       else:
         try:
           info_url = u + 'ssh_info'
-          info = urllib2.urlopen(info_url).read()
+          info = urllib.request.urlopen(info_url).read()
           if '<' in info:
             # Assume the server gave us some sort of HTML
             # response back, like maybe a login page.
@@ -592,9 +604,9 @@
           else:
             host, port = info.split()
             self._review_url = self._SshReviewUrl(userEmail, host, port)
-        except urllib2.HTTPError as e:
+        except urllib.error.HTTPError as e:
           raise UploadError('%s: %s' % (self.review, str(e)))
-        except urllib2.URLError as e:
+        except urllib.error.URLError as e:
           raise UploadError('%s: %s' % (self.review, str(e)))
 
         REVIEW_CACHE[u] = self._review_url
@@ -645,7 +657,7 @@
     self._Set('url', self.url)
     self._Set('review', self.review)
     self._Set('projectname', self.projectname)
-    self._Set('fetch', map(lambda x: str(x), self.fetch))
+    self._Set('fetch', map(str, self.fetch))
 
   def _Set(self, key, value):
     key = 'remote.%s.%s' % (self.name, key)
diff --git a/git_refs.py b/git_refs.py
index 18c9230..cfeffba 100644
--- a/git_refs.py
+++ b/git_refs.py
@@ -138,14 +138,14 @@
   def _ReadLoose1(self, path, name):
     try:
       fd = open(path, 'rb')
-    except:
+    except IOError:
       return
 
     try:
       try:
         mtime = os.path.getmtime(path)
         ref_id = fd.readline()
-      except:
+      except (IOError, OSError):
         return
     finally:
       fd.close()
diff --git a/hooks/commit-msg b/hooks/commit-msg
index 172a178..b37dfaa 100755
--- a/hooks/commit-msg
+++ b/hooks/commit-msg
@@ -1,5 +1,5 @@
 #!/bin/sh
-# From Gerrit Code Review 2.5-rc0
+# From Gerrit Code Review 2.5.2
 #
 # Part of Gerrit Code Review (http://code.google.com/p/gerrit/)
 #
@@ -18,6 +18,8 @@
 # limitations under the License.
 #
 
+unset GREP_OPTIONS
+
 CHANGE_ID_AFTER="Bug|Issue"
 MSG="$1"
 
diff --git a/main.py b/main.py
index ba40d56..9cc2639 100755
--- a/main.py
+++ b/main.py
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env python
 #
 # Copyright (C) 2008 The Android Open Source Project
 #
@@ -14,23 +14,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-magic='--calling-python-from-/bin/sh--'
-"""exec" python -E "$0" "$@" """#$magic"
-if __name__ == '__main__':
-  import sys
-  if sys.argv[-1] == '#%s' % magic:
-    del sys.argv[-1]
-del magic
-
+from __future__ import print_function
 import getpass
 import imp
 import netrc
 import optparse
 import os
-import re
 import sys
 import time
-import urllib2
+try:
+  import urllib2
+except ImportError:
+  # For python3
+  import urllib.request
+else:
+  # For python2
+  urllib = imp.new_module('urllib')
+  urllib.request = urllib2
 
 from trace import SetTrace
 from git_command import git, GitCommand
@@ -41,6 +41,8 @@
 from editor import Editor
 from error import DownloadError
 from error import ManifestInvalidRevisionError
+from error import ManifestParseError
+from error import NoManifestException
 from error import NoSuchProjectError
 from error import RepoChangedException
 from manifest_xml import XmlManifest
@@ -79,7 +81,7 @@
     name = None
     glob = []
 
-    for i in xrange(0, len(argv)):
+    for i in range(len(argv)):
       if not argv[i].startswith('-'):
         name = argv[i]
         if i > 0:
@@ -98,15 +100,14 @@
       if name == 'help':
         name = 'version'
       else:
-        print >>sys.stderr, 'fatal: invalid usage of --version'
+        print('fatal: invalid usage of --version', file=sys.stderr)
         return 1
 
     try:
       cmd = self.commands[name]
     except KeyError:
-      print >>sys.stderr,\
-            "repo: '%s' is not a repo command.  See 'repo help'."\
-            % name
+      print("repo: '%s' is not a repo command.  See 'repo help'." % name,
+            file=sys.stderr)
       return 1
 
     cmd.repodir = self.repodir
@@ -114,12 +115,12 @@
     Editor.globalConfig = cmd.manifest.globalConfig
 
     if not isinstance(cmd, MirrorSafeCommand) and cmd.manifest.IsMirror:
-      print >>sys.stderr, \
-            "fatal: '%s' requires a working directory"\
-            % name
+      print("fatal: '%s' requires a working directory" % name,
+            file=sys.stderr)
       return 1
 
     copts, cargs = cmd.OptionParser.parse_args(argv)
+    copts = cmd.ReadEnvironmentOptions(copts)
 
     if not gopts.no_pager and not isinstance(cmd, InteractiveCommand):
       config = cmd.manifest.globalConfig
@@ -132,33 +133,35 @@
       if use_pager:
         RunPager(config)
 
+    start = time.time()
     try:
-      start = time.time()
-      try:
-        result = cmd.Execute(copts, cargs)
-      finally:
-        elapsed = time.time() - start
-        hours, remainder = divmod(elapsed, 3600)
-        minutes, seconds = divmod(remainder, 60)
-        if gopts.time:
-          if hours == 0:
-            print >>sys.stderr, 'real\t%dm%.3fs' \
-              % (minutes, seconds)
-          else:
-            print >>sys.stderr, 'real\t%dh%dm%.3fs' \
-              % (hours, minutes, seconds)
+      result = cmd.Execute(copts, cargs)
     except DownloadError as e:
-      print >>sys.stderr, 'error: %s' % str(e)
-      return 1
+      print('error: %s' % str(e), file=sys.stderr)
+      result = 1
     except ManifestInvalidRevisionError as e:
-      print >>sys.stderr, 'error: %s' % str(e)
-      return 1
+      print('error: %s' % str(e), file=sys.stderr)
+      result = 1
+    except NoManifestException as e:
+      print('error: manifest required for this command -- please run init',
+            file=sys.stderr)
+      result = 1
     except NoSuchProjectError as e:
       if e.name:
-        print >>sys.stderr, 'error: project %s not found' % e.name
+        print('error: project %s not found' % e.name, file=sys.stderr)
       else:
-        print >>sys.stderr, 'error: no project in current directory'
-      return 1
+        print('error: no project in current directory', file=sys.stderr)
+      result = 1
+    finally:
+      elapsed = time.time() - start
+      hours, remainder = divmod(elapsed, 3600)
+      minutes, seconds = divmod(remainder, 60)
+      if gopts.time:
+        if hours == 0:
+          print('real\t%dm%.3fs' % (minutes, seconds), file=sys.stderr)
+        else:
+          print('real\t%dh%dm%.3fs' % (hours, minutes, seconds),
+                file=sys.stderr)
 
     return result
 
@@ -183,36 +186,35 @@
     repo_path = '~/bin/repo'
 
   if not ver:
-    print >>sys.stderr, 'no --wrapper-version argument'
+    print('no --wrapper-version argument', file=sys.stderr)
     sys.exit(1)
 
   exp = _CurrentWrapperVersion()
-  ver = tuple(map(lambda x: int(x), ver.split('.')))
+  ver = tuple(map(int, ver.split('.')))
   if len(ver) == 1:
     ver = (0, ver[0])
 
+  exp_str = '.'.join(map(str, exp))
   if exp[0] > ver[0] or ver < (0, 4):
-    exp_str = '.'.join(map(lambda x: str(x), exp))
-    print >>sys.stderr, """
+    print("""
 !!! A new repo command (%5s) is available.    !!!
 !!! You must upgrade before you can continue:   !!!
 
     cp %s %s
-""" % (exp_str, _MyWrapperPath(), repo_path)
+""" % (exp_str, _MyWrapperPath(), repo_path), file=sys.stderr)
     sys.exit(1)
 
   if exp > ver:
-    exp_str = '.'.join(map(lambda x: str(x), exp))
-    print >>sys.stderr, """
+    print("""
 ... A new repo command (%5s) is available.
 ... You should upgrade soon:
 
     cp %s %s
-""" % (exp_str, _MyWrapperPath(), repo_path)
+""" % (exp_str, _MyWrapperPath(), repo_path), file=sys.stderr)
 
 def _CheckRepoDir(repo_dir):
   if not repo_dir:
-    print >>sys.stderr, 'no --repo-dir argument'
+    print('no --repo-dir argument', file=sys.stderr)
     sys.exit(1)
 
 def _PruneOptions(argv, opt):
@@ -264,11 +266,11 @@
     _user_agent = 'git-repo/%s (%s) git/%s Python/%d.%d.%d' % (
       repo_version,
       os_name,
-      '.'.join(map(lambda d: str(d), git.version_tuple())),
+      '.'.join(map(str, git.version_tuple())),
       py_version[0], py_version[1], py_version[2])
   return _user_agent
 
-class _UserAgentHandler(urllib2.BaseHandler):
+class _UserAgentHandler(urllib.request.BaseHandler):
   def http_request(self, req):
     req.add_header('User-Agent', _UserAgent())
     return req
@@ -278,22 +280,22 @@
     return req
 
 def _AddPasswordFromUserInput(handler, msg, req):
-    # If repo could not find auth info from netrc, try to get it from user input
-    url = req.get_full_url()
-    user, password = handler.passwd.find_user_password(None, url)
-    if user is None:
-      print msg
-      try:
-        user = raw_input('User: ')
-        password = getpass.getpass()
-      except KeyboardInterrupt:
-        return
-      handler.passwd.add_password(None, url, user, password)
+  # If repo could not find auth info from netrc, try to get it from user input
+  url = req.get_full_url()
+  user, password = handler.passwd.find_user_password(None, url)
+  if user is None:
+    print(msg)
+    try:
+      user = raw_input('User: ')
+      password = getpass.getpass()
+    except KeyboardInterrupt:
+      return
+    handler.passwd.add_password(None, url, user, password)
 
-class _BasicAuthHandler(urllib2.HTTPBasicAuthHandler):
+class _BasicAuthHandler(urllib.request.HTTPBasicAuthHandler):
   def http_error_401(self, req, fp, code, msg, headers):
     _AddPasswordFromUserInput(self, msg, req)
-    return urllib2.HTTPBasicAuthHandler.http_error_401(
+    return urllib.request.HTTPBasicAuthHandler.http_error_401(
       self, req, fp, code, msg, headers)
 
   def http_error_auth_reqed(self, authreq, host, req, headers):
@@ -303,7 +305,7 @@
         val = val.replace('\n', '')
         old_add_header(name, val)
       req.add_header = _add_header
-      return urllib2.AbstractBasicAuthHandler.http_error_auth_reqed(
+      return urllib.request.AbstractBasicAuthHandler.http_error_auth_reqed(
         self, authreq, host, req, headers)
     except:
       reset = getattr(self, 'reset_retry_count', None)
@@ -313,10 +315,10 @@
         self.retried = 0
       raise
 
-class _DigestAuthHandler(urllib2.HTTPDigestAuthHandler):
+class _DigestAuthHandler(urllib.request.HTTPDigestAuthHandler):
   def http_error_401(self, req, fp, code, msg, headers):
     _AddPasswordFromUserInput(self, msg, req)
-    return urllib2.HTTPDigestAuthHandler.http_error_401(
+    return urllib.request.HTTPDigestAuthHandler.http_error_401(
       self, req, fp, code, msg, headers)
 
   def http_error_auth_reqed(self, auth_header, host, req, headers):
@@ -326,7 +328,7 @@
         val = val.replace('\n', '')
         old_add_header(name, val)
       req.add_header = _add_header
-      return urllib2.AbstractDigestAuthHandler.http_error_auth_reqed(
+      return urllib.request.AbstractDigestAuthHandler.http_error_auth_reqed(
         self, auth_header, host, req, headers)
     except:
       reset = getattr(self, 'reset_retry_count', None)
@@ -339,7 +341,7 @@
 def init_http():
   handlers = [_UserAgentHandler()]
 
-  mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
+  mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
   try:
     n = netrc.netrc()
     for host in n.hosts:
@@ -355,11 +357,11 @@
 
   if 'http_proxy' in os.environ:
     url = os.environ['http_proxy']
-    handlers.append(urllib2.ProxyHandler({'http': url, 'https': url}))
+    handlers.append(urllib.request.ProxyHandler({'http': url, 'https': url}))
   if 'REPO_CURL_VERBOSE' in os.environ:
-    handlers.append(urllib2.HTTPHandler(debuglevel=1))
-    handlers.append(urllib2.HTTPSHandler(debuglevel=1))
-  urllib2.install_opener(urllib2.build_opener(*handlers))
+    handlers.append(urllib.request.HTTPHandler(debuglevel=1))
+    handlers.append(urllib.request.HTTPSHandler(debuglevel=1))
+  urllib.request.install_opener(urllib.request.build_opener(*handlers))
 
 def _Main(argv):
   result = 0
@@ -389,6 +391,10 @@
     finally:
       close_ssh()
   except KeyboardInterrupt:
+    print('aborted by user', file=sys.stderr)
+    result = 1
+  except ManifestParseError as mpe:
+    print('fatal: %s' % mpe, file=sys.stderr)
     result = 1
   except RepoChangedException as rce:
     # If repo changed, re-exec ourselves.
@@ -398,8 +404,8 @@
     try:
       os.execv(__file__, argv)
     except OSError as e:
-      print >>sys.stderr, 'fatal: cannot restart repo after upgrade'
-      print >>sys.stderr, 'fatal: %s' % e
+      print('fatal: cannot restart repo after upgrade', file=sys.stderr)
+      print('fatal: %s' % e, file=sys.stderr)
       result = 128
 
   sys.exit(result)
diff --git a/manifest_xml.py b/manifest_xml.py
index dd163be..53f3353 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import itertools
 import os
 import re
@@ -27,6 +28,7 @@
 
 MANIFEST_FILE_NAME = 'manifest.xml'
 LOCAL_MANIFEST_NAME = 'local_manifest.xml'
+LOCAL_MANIFESTS_DIR_NAME = 'local_manifests'
 
 urlparse.uses_relative.extend(['ssh', 'git'])
 urlparse.uses_netloc.extend(['ssh', 'git'])
@@ -38,6 +40,7 @@
   remote = None
   sync_j = 1
   sync_c = False
+  sync_s = False
 
 class _XmlRemote(object):
   def __init__(self,
@@ -53,15 +56,28 @@
     self.reviewUrl = review
     self.resolvedFetchUrl = self._resolveFetchUrl()
 
+  def __eq__(self, other):
+    return self.__dict__ == other.__dict__
+
+  def __ne__(self, other):
+    return self.__dict__ != other.__dict__
+
   def _resolveFetchUrl(self):
     url = self.fetchUrl.rstrip('/')
     manifestUrl = self.manifestUrl.rstrip('/')
+    p = manifestUrl.startswith('persistent-http')
+    if p:
+      manifestUrl = manifestUrl[len('persistent-'):]
+
     # urljoin will get confused if there is no scheme in the base url
     # ie, if manifestUrl is of the form <hostname:port>
     if manifestUrl.find(':') != manifestUrl.find('/') - 1:
-        manifestUrl = 'gopher://' + manifestUrl
+      manifestUrl = 'gopher://' + manifestUrl
     url = urlparse.urljoin(manifestUrl, url)
-    return re.sub(r'^gopher://', '', url)
+    url = re.sub(r'^gopher://', '', url)
+    if p:
+      url = 'persistent-' + url
+    return url
 
   def ToRemoteSpec(self, projectName):
     url = self.resolvedFetchUrl.rstrip('/') + '/' + projectName
@@ -110,11 +126,11 @@
     self.Override(name)
 
     try:
-      if os.path.exists(self.manifestFile):
+      if os.path.lexists(self.manifestFile):
         os.remove(self.manifestFile)
       os.symlink('manifests/%s' % name, self.manifestFile)
-    except OSError:
-      raise ManifestParseError('cannot link manifest %s' % name)
+    except OSError as e:
+      raise ManifestParseError('cannot link manifest %s: %s' % (name, str(e)))
 
   def _RemoteToXml(self, r, doc, root):
     e = doc.createElement('remote')
@@ -130,9 +146,8 @@
     mp = self.manifestProject
 
     groups = mp.config.GetString('manifest.groups')
-    if not groups:
-      groups = 'all'
-    groups = [x for x in re.split(r'[,\s]+', groups) if x]
+    if groups:
+      groups = [x for x in re.split(r'[,\s]+', groups) if x]
 
     doc = xml.dom.minidom.Document()
     root = doc.createElement('manifest')
@@ -170,6 +185,9 @@
     if d.sync_c:
       have_default = True
       e.setAttribute('sync-c', 'true')
+    if d.sync_s:
+      have_default = True
+      e.setAttribute('sync-s', 'true')
     if have_default:
       root.appendChild(e)
       root.appendChild(doc.createTextNode(''))
@@ -180,20 +198,25 @@
       root.appendChild(e)
       root.appendChild(doc.createTextNode(''))
 
-    sort_projects = list(self.projects.keys())
-    sort_projects.sort()
+    def output_projects(parent, parent_node, projects):
+      for p in projects:
+        output_project(parent, parent_node, self.projects[p])
 
-    for p in sort_projects:
-      p = self.projects[p]
-
+    def output_project(parent, parent_node, p):
       if not p.MatchesGroups(groups):
-        continue
+        return
+
+      name = p.name
+      relpath = p.relpath
+      if parent:
+        name = self._UnjoinName(parent.name, name)
+        relpath = self._UnjoinRelpath(parent.relpath, relpath)
 
       e = doc.createElement('project')
-      root.appendChild(e)
-      e.setAttribute('name', p.name)
-      if p.relpath != p.name:
-        e.setAttribute('path', p.relpath)
+      parent_node.appendChild(e)
+      e.setAttribute('name', name)
+      if relpath != name:
+        e.setAttribute('path', relpath)
       if not d.remote or p.remote.name != d.remote.name:
         e.setAttribute('remote', p.remote.name)
       if peg_rev:
@@ -231,6 +254,19 @@
       if p.sync_c:
         e.setAttribute('sync-c', 'true')
 
+      if p.sync_s:
+        e.setAttribute('sync-s', 'true')
+
+      if p.subprojects:
+        sort_projects = [subp.name for subp in p.subprojects]
+        sort_projects.sort()
+        output_projects(p, e, sort_projects)
+
+    sort_projects = [key for key in self.projects.keys()
+                     if not self.projects[key].parent]
+    sort_projects.sort()
+    output_projects(None, root, sort_projects)
+
     if self._repo_hooks_project:
       root.appendChild(doc.createTextNode(''))
       e = doc.createElement('repo-hooks')
@@ -299,9 +335,30 @@
 
       local = os.path.join(self.repodir, LOCAL_MANIFEST_NAME)
       if os.path.exists(local):
+        print('warning: %s is deprecated; put local manifests in %s instead'
+              % (LOCAL_MANIFEST_NAME, LOCAL_MANIFESTS_DIR_NAME),
+              file=sys.stderr)
         nodes.append(self._ParseManifestXml(local, self.repodir))
 
-      self._ParseManifest(nodes)
+      local_dir = os.path.abspath(os.path.join(self.repodir, LOCAL_MANIFESTS_DIR_NAME))
+      try:
+        for local_file in sorted(os.listdir(local_dir)):
+          if local_file.endswith('.xml'):
+            try:
+              local = os.path.join(local_dir, local_file)
+              nodes.append(self._ParseManifestXml(local, self.repodir))
+            except ManifestParseError as e:
+              print('%s' % str(e), file=sys.stderr)
+      except OSError:
+        pass
+
+      try:
+        self._ParseManifest(nodes)
+      except ManifestParseError as e:
+        # There was a problem parsing, unload ourselves in case they catch
+        # this error and try again later, we will show the correct error
+        self._Unload()
+        raise e
 
       if self.IsMirror:
         self._AddMetaProjectMirror(self.repoProject)
@@ -310,7 +367,11 @@
       self._loaded = True
 
   def _ParseManifestXml(self, path, include_root):
-    root = xml.dom.minidom.parse(path)
+    try:
+      root = xml.dom.minidom.parse(path)
+    except (OSError, xml.parsers.expat.ExpatError) as e:
+      raise ManifestParseError("error parsing manifest %s: %s" % (path, e))
+
     if not root or not root.childNodes:
       raise ManifestParseError("no root node in %s" % (path,))
 
@@ -323,35 +384,38 @@
     nodes = []
     for node in manifest.childNodes:  # pylint:disable=W0631
                                       # We only get here if manifest is initialised
-        if node.nodeName == 'include':
-            name = self._reqatt(node, 'name')
-            fp = os.path.join(include_root, name)
-            if not os.path.isfile(fp):
-                raise ManifestParseError, \
-                    "include %s doesn't exist or isn't a file" % \
-                    (name,)
-            try:
-                nodes.extend(self._ParseManifestXml(fp, include_root))
-            # should isolate this to the exact exception, but that's
-            # tricky.  actual parsing implementation may vary.
-            except (KeyboardInterrupt, RuntimeError, SystemExit):
-                raise
-            except Exception as e:
-                raise ManifestParseError(
-                    "failed parsing included manifest %s: %s", (name, e))
-        else:
-          nodes.append(node)
+      if node.nodeName == 'include':
+        name = self._reqatt(node, 'name')
+        fp = os.path.join(include_root, name)
+        if not os.path.isfile(fp):
+          raise ManifestParseError, \
+              "include %s doesn't exist or isn't a file" % \
+              (name,)
+        try:
+          nodes.extend(self._ParseManifestXml(fp, include_root))
+        # should isolate this to the exact exception, but that's
+        # tricky.  actual parsing implementation may vary.
+        except (KeyboardInterrupt, RuntimeError, SystemExit):
+          raise
+        except Exception as e:
+          raise ManifestParseError(
+              "failed parsing included manifest %s: %s", (name, e))
+      else:
+        nodes.append(node)
     return nodes
 
   def _ParseManifest(self, node_list):
     for node in itertools.chain(*node_list):
       if node.nodeName == 'remote':
         remote = self._ParseRemote(node)
-        if self._remotes.get(remote.name):
-          raise ManifestParseError(
-              'duplicate remote %s in %s' %
-              (remote.name, self.manifestFile))
-        self._remotes[remote.name] = remote
+        if remote:
+          if remote.name in self._remotes:
+            if remote != self._remotes[remote.name]:
+              raise ManifestParseError(
+                  'remote %s already exists with different attributes' %
+                  (remote.name))
+          else:
+            self._remotes[remote.name] = remote
 
     for node in itertools.chain(*node_list):
       if node.nodeName == 'default':
@@ -375,19 +439,24 @@
       if node.nodeName == 'manifest-server':
         url = self._reqatt(node, 'url')
         if self._manifest_server is not None:
-            raise ManifestParseError(
-                'duplicate manifest-server in %s' %
-                (self.manifestFile))
+          raise ManifestParseError(
+              'duplicate manifest-server in %s' %
+              (self.manifestFile))
         self._manifest_server = url
 
+    def recursively_add_projects(project):
+      if self._projects.get(project.name):
+        raise ManifestParseError(
+            'duplicate project %s in %s' %
+            (project.name, self.manifestFile))
+      self._projects[project.name] = project
+      for subproject in project.subprojects:
+        recursively_add_projects(subproject)
+
     for node in itertools.chain(*node_list):
       if node.nodeName == 'project':
         project = self._ParseProject(node)
-        if self._projects.get(project.name):
-          raise ManifestParseError(
-              'duplicate project %s in %s' %
-              (project.name, self.manifestFile))
-        self._projects[project.name] = project
+        recursively_add_projects(project)
       if node.nodeName == 'repo-hooks':
         # Get the name of the project and the (space-separated) list of enabled.
         repo_hooks_project = self._reqatt(node, 'in-project')
@@ -414,9 +483,8 @@
         try:
           del self._projects[name]
         except KeyError:
-          raise ManifestParseError(
-              'project %s not found' %
-              (name))
+          raise ManifestParseError('remove-project element specifies non-existent '
+                                   'project: %s' % name)
 
         # If the manifest removes the hooks project, treat it as if it deleted
         # the repo-hooks element too.
@@ -496,6 +564,12 @@
       d.sync_c = False
     else:
       d.sync_c = sync_c.lower() in ("yes", "true", "1")
+
+    sync_s = node.getAttribute('sync-s')
+    if not sync_s:
+      d.sync_s = False
+    else:
+      d.sync_s = sync_s.lower() in ("yes", "true", "1")
     return d
 
   def _ParseNotice(self, node):
@@ -537,11 +611,19 @@
 
     return '\n'.join(cleanLines)
 
-  def _ParseProject(self, node):
+  def _JoinName(self, parent_name, name):
+    return os.path.join(parent_name, name)
+
+  def _UnjoinName(self, parent_name, name):
+    return os.path.relpath(name, parent_name)
+
+  def _ParseProject(self, node, parent = None):
     """
     reads a <project> element from the manifest file
     """
     name = self._reqatt(node, 'name')
+    if parent:
+      name = self._JoinName(parent.name, name)
 
     remote = self._get_remote(node)
     if remote is None:
@@ -579,44 +661,80 @@
     else:
       sync_c = sync_c.lower() in ("yes", "true", "1")
 
+    sync_s = node.getAttribute('sync-s')
+    if not sync_s:
+      sync_s = self._default.sync_s
+    else:
+      sync_s = sync_s.lower() in ("yes", "true", "1")
+
     upstream = node.getAttribute('upstream')
 
     groups = ''
     if node.hasAttribute('groups'):
       groups = node.getAttribute('groups')
-    groups = [x for x in re.split('[,\s]+', groups) if x]
+    groups = [x for x in re.split(r'[,\s]+', groups) if x]
 
-    default_groups = ['all', 'name:%s' % name, 'path:%s' % path]
-    groups.extend(set(default_groups).difference(groups))
-
-    if self.IsMirror:
-      worktree = None
-      gitdir = os.path.join(self.topdir, '%s.git' % name)
+    if parent is None:
+      relpath, worktree, gitdir = self.GetProjectPaths(name, path)
     else:
-      worktree = os.path.join(self.topdir, path).replace('\\', '/')
-      gitdir = os.path.join(self.repodir, 'projects/%s.git' % path)
+      relpath, worktree, gitdir = self.GetSubprojectPaths(parent, path)
+
+    default_groups = ['all', 'name:%s' % name, 'path:%s' % relpath]
+    groups.extend(set(default_groups).difference(groups))
 
     project = Project(manifest = self,
                       name = name,
                       remote = remote.ToRemoteSpec(name),
                       gitdir = gitdir,
                       worktree = worktree,
-                      relpath = path,
+                      relpath = relpath,
                       revisionExpr = revisionExpr,
                       revisionId = None,
                       rebase = rebase,
                       groups = groups,
                       sync_c = sync_c,
-                      upstream = upstream)
+                      sync_s = sync_s,
+                      upstream = upstream,
+                      parent = parent)
 
     for n in node.childNodes:
       if n.nodeName == 'copyfile':
         self._ParseCopyFile(project, n)
       if n.nodeName == 'annotation':
         self._ParseAnnotation(project, n)
+      if n.nodeName == 'project':
+        project.subprojects.append(self._ParseProject(n, parent = project))
 
     return project
 
+  def GetProjectPaths(self, name, path):
+    relpath = path
+    if self.IsMirror:
+      worktree = None
+      gitdir = os.path.join(self.topdir, '%s.git' % name)
+    else:
+      worktree = os.path.join(self.topdir, path).replace('\\', '/')
+      gitdir = os.path.join(self.repodir, 'projects', '%s.git' % path)
+    return relpath, worktree, gitdir
+
+  def GetSubprojectName(self, parent, submodule_path):
+    return os.path.join(parent.name, submodule_path)
+
+  def _JoinRelpath(self, parent_relpath, relpath):
+    return os.path.join(parent_relpath, relpath)
+
+  def _UnjoinRelpath(self, parent_relpath, relpath):
+    return os.path.relpath(relpath, parent_relpath)
+
+  def GetSubprojectPaths(self, parent, path):
+    relpath = self._JoinRelpath(parent.relpath, path)
+    gitdir = os.path.join(parent.gitdir, 'subprojects', '%s.git' % path)
+    if self.IsMirror:
+      worktree = None
+    else:
+      worktree = os.path.join(parent.worktree, path).replace('\\', '/')
+    return relpath, worktree, gitdir
+
   def _ParseCopyFile(self, project, node):
     src = self._reqatt(node, 'src')
     dest = self._reqatt(node, 'dest')
diff --git a/pager.py b/pager.py
index 888b108..c621141 100755
--- a/pager.py
+++ b/pager.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import select
 import sys
@@ -49,7 +50,7 @@
 
     _BecomePager(pager)
   except Exception:
-    print >>sys.stderr, "fatal: cannot start pager '%s'" % pager
+    print("fatal: cannot start pager '%s'" % pager, file=sys.stderr)
     sys.exit(255)
 
 def _SelectPager(globalConfig):
diff --git a/project.py b/project.py
index 2f47169..ba7898e 100644
--- a/project.py
+++ b/project.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import traceback
 import errno
 import filecmp
@@ -22,13 +23,15 @@
 import stat
 import subprocess
 import sys
+import tempfile
 import time
 
 from color import Coloring
-from git_command import GitCommand
+from git_command import GitCommand, git_require
 from git_config import GitConfig, IsId, GetSchemeFromUrl, ID_RE
 from error import GitError, HookError, UploadError
 from error import ManifestInvalidRevisionError
+from error import NoManifestException
 from trace import IsTrace, Trace
 
 from git_refs import GitRefs, HEAD, R_HEADS, R_TAGS, R_PUB, R_M
@@ -50,7 +53,7 @@
 
 def _error(fmt, *args):
   msg = fmt % args
-  print >>sys.stderr, 'error: %s' % msg
+  print('error: %s' % msg, file=sys.stderr)
 
 def not_rev(r):
   return '^' + r
@@ -359,7 +362,7 @@
                  '(yes/yes-never-ask-again/NO)? ') % (
                  self._GetMustVerb(), self._script_fullpath)
       response = raw_input(prompt).lower()
-      print
+      print()
 
       # User is doing a one-time approval.
       if response in ('y', 'yes'):
@@ -484,7 +487,30 @@
                rebase = True,
                groups = None,
                sync_c = False,
-               upstream = None):
+               sync_s = False,
+               upstream = None,
+               parent = None,
+               is_derived = False):
+    """Init a Project object.
+
+    Args:
+      manifest: The XmlManifest object.
+      name: The `name` attribute of manifest.xml's project element.
+      remote: RemoteSpec object specifying its remote's properties.
+      gitdir: Absolute path of git directory.
+      worktree: Absolute path of git working tree.
+      relpath: Relative path of git working tree to repo's top directory.
+      revisionExpr: The `revision` attribute of manifest.xml's project element.
+      revisionId: git commit id for checking out.
+      rebase: The `rebase` attribute of manifest.xml's project element.
+      groups: The `groups` attribute of manifest.xml's project element.
+      sync_c: The `sync-c` attribute of manifest.xml's project element.
+      sync_s: The `sync-s` attribute of manifest.xml's project element.
+      upstream: The `upstream` attribute of manifest.xml's project element.
+      parent: The parent Project object.
+      is_derived: False if the project was explicitly defined in the manifest;
+                  True if the project is a discovered submodule.
+    """
     self.manifest = manifest
     self.name = name
     self.remote = remote
@@ -506,7 +532,11 @@
     self.rebase = rebase
     self.groups = groups
     self.sync_c = sync_c
+    self.sync_s = sync_s
     self.upstream = upstream
+    self.parent = parent
+    self.is_derived = is_derived
+    self.subprojects = []
 
     self.snapshots = {}
     self.copyfiles = []
@@ -527,6 +557,10 @@
     self.enabled_repo_hooks = []
 
   @property
+  def Derived(self):
+    return self.is_derived
+
+  @property
   def Exists(self):
     return os.path.isdir(self.gitdir)
 
@@ -555,7 +589,7 @@
                                '--unmerged',
                                '--ignore-missing',
                                '--refresh')
-    if self.work_git.DiffZ('diff-index','-M','--cached',HEAD):
+    if self.work_git.DiffZ('diff-index', '-M', '--cached', HEAD):
       return True
     if self.work_git.DiffZ('diff-files'):
       return True
@@ -584,14 +618,14 @@
     return self._userident_email
 
   def _LoadUserIdentity(self):
-      u = self.bare_git.var('GIT_COMMITTER_IDENT')
-      m = re.compile("^(.*) <([^>]*)> ").match(u)
-      if m:
-        self._userident_name = m.group(1)
-        self._userident_email = m.group(2)
-      else:
-        self._userident_name = ''
-        self._userident_email = ''
+    u = self.bare_git.var('GIT_COMMITTER_IDENT')
+    m = re.compile("^(.*) <([^>]*)> ").match(u)
+    if m:
+      self._userident_name = m.group(1)
+      self._userident_email = m.group(2)
+    else:
+      self._userident_name = ''
+      self._userident_email = ''
 
   def GetRemote(self, name):
     """Get the configuration for a single remote.
@@ -683,9 +717,9 @@
     if not os.path.isdir(self.worktree):
       if output_redir == None:
         output_redir = sys.stdout
-      print >>output_redir, ''
-      print >>output_redir, 'project %s/' % self.relpath
-      print >>output_redir, '  missing (run "repo sync")'
+      print(file=output_redir)
+      print('project %s/' % self.relpath, file=output_redir)
+      print('  missing (run "repo sync")', file=output_redir)
       return
 
     self.work_git.update_index('-q',
@@ -785,7 +819,7 @@
         out.project('project %s/' % self.relpath)
         out.nl()
         has_diff = True
-      print line[:-1]
+      print(line[:-1])
     p.Wait()
 
 
@@ -1012,6 +1046,10 @@
     self.CleanPublishedCache(all_refs)
     revid = self.GetRevisionId(all_refs)
 
+    def _doff():
+      self._FastForward(revid)
+      self._CopyFiles()
+
     self._InitWorkTree()
     head = self.work_git.GetHead()
     if head.startswith(R_HEADS):
@@ -1090,9 +1128,6 @@
         # All published commits are merged, and thus we are a
         # strict subset.  We can fast-forward safely.
         #
-        def _doff():
-          self._FastForward(revid)
-          self._CopyFiles()
         syncbuf.later1(self, _doff)
         return
 
@@ -1155,9 +1190,6 @@
         syncbuf.fail(self, e)
         return
     else:
-      def _doff():
-        self._FastForward(revid)
-        self._CopyFiles()
       syncbuf.later1(self, _doff)
 
   def AddCopyFile(self, src, dest, absdest):
@@ -1177,7 +1209,7 @@
     cmd = ['fetch', remote.name]
     cmd.append('refs/changes/%2.2d/%d/%d' \
                % (change_id % 100, change_id, patch_id))
-    cmd.extend(map(lambda x: str(x), remote.fetch))
+    cmd.extend(map(str, remote.fetch))
     if GitCommand(self, cmd, bare=True).Wait() != 0:
       return None
     return DownloadedChange(self,
@@ -1370,6 +1402,149 @@
     return kept
 
 
+## Submodule Management ##
+
+  def GetRegisteredSubprojects(self):
+    result = []
+    def rec(subprojects):
+      if not subprojects:
+        return
+      result.extend(subprojects)
+      for p in subprojects:
+        rec(p.subprojects)
+    rec(self.subprojects)
+    return result
+
+  def _GetSubmodules(self):
+    # Unfortunately we cannot call `git submodule status --recursive` here
+    # because the working tree might not exist yet, and it cannot be used
+    # without a working tree in its current implementation.
+
+    def get_submodules(gitdir, rev):
+      # Parse .gitmodules for submodule sub_paths and sub_urls
+      sub_paths, sub_urls = parse_gitmodules(gitdir, rev)
+      if not sub_paths:
+        return []
+      # Run `git ls-tree` to read SHAs of submodule object, which happen to be
+      # revision of submodule repository
+      sub_revs = git_ls_tree(gitdir, rev, sub_paths)
+      submodules = []
+      for sub_path, sub_url in zip(sub_paths, sub_urls):
+        try:
+          sub_rev = sub_revs[sub_path]
+        except KeyError:
+          # Ignore non-exist submodules
+          continue
+        submodules.append((sub_rev, sub_path, sub_url))
+      return submodules
+
+    re_path = re.compile(r'^submodule\.([^.]+)\.path=(.*)$')
+    re_url = re.compile(r'^submodule\.([^.]+)\.url=(.*)$')
+    def parse_gitmodules(gitdir, rev):
+      cmd = ['cat-file', 'blob', '%s:.gitmodules' % rev]
+      try:
+        p = GitCommand(None, cmd, capture_stdout = True, capture_stderr = True,
+                       bare = True, gitdir = gitdir)
+      except GitError:
+        return [], []
+      if p.Wait() != 0:
+        return [], []
+
+      gitmodules_lines = []
+      fd, temp_gitmodules_path = tempfile.mkstemp()
+      try:
+        os.write(fd, p.stdout)
+        os.close(fd)
+        cmd = ['config', '--file', temp_gitmodules_path, '--list']
+        p = GitCommand(None, cmd, capture_stdout = True, capture_stderr = True,
+                       bare = True, gitdir = gitdir)
+        if p.Wait() != 0:
+          return [], []
+        gitmodules_lines = p.stdout.split('\n')
+      except GitError:
+        return [], []
+      finally:
+        os.remove(temp_gitmodules_path)
+
+      names = set()
+      paths = {}
+      urls = {}
+      for line in gitmodules_lines:
+        if not line:
+          continue
+        m = re_path.match(line)
+        if m:
+          names.add(m.group(1))
+          paths[m.group(1)] = m.group(2)
+          continue
+        m = re_url.match(line)
+        if m:
+          names.add(m.group(1))
+          urls[m.group(1)] = m.group(2)
+          continue
+      names = sorted(names)
+      return ([paths.get(name, '') for name in names],
+              [urls.get(name, '') for name in names])
+
+    def git_ls_tree(gitdir, rev, paths):
+      cmd = ['ls-tree', rev, '--']
+      cmd.extend(paths)
+      try:
+        p = GitCommand(None, cmd, capture_stdout = True, capture_stderr = True,
+                       bare = True, gitdir = gitdir)
+      except GitError:
+        return []
+      if p.Wait() != 0:
+        return []
+      objects = {}
+      for line in p.stdout.split('\n'):
+        if not line.strip():
+          continue
+        object_rev, object_path = line.split()[2:4]
+        objects[object_path] = object_rev
+      return objects
+
+    try:
+      rev = self.GetRevisionId()
+    except GitError:
+      return []
+    return get_submodules(self.gitdir, rev)
+
+  def GetDerivedSubprojects(self):
+    result = []
+    if not self.Exists:
+      # If git repo does not exist yet, querying its submodules will
+      # mess up its states; so return here.
+      return result
+    for rev, path, url in self._GetSubmodules():
+      name = self.manifest.GetSubprojectName(self, path)
+      project = self.manifest.projects.get(name)
+      if project:
+        result.extend(project.GetDerivedSubprojects())
+        continue
+      relpath, worktree, gitdir = self.manifest.GetSubprojectPaths(self, path)
+      remote = RemoteSpec(self.remote.name,
+                          url = url,
+                          review = self.remote.review)
+      subproject = Project(manifest = self.manifest,
+                           name = name,
+                           remote = remote,
+                           gitdir = gitdir,
+                           worktree = worktree,
+                           relpath = relpath,
+                           revisionExpr = self.revisionExpr,
+                           revisionId = rev,
+                           rebase = self.rebase,
+                           groups = self.groups,
+                           sync_c = self.sync_c,
+                           sync_s = self.sync_s,
+                           parent = self,
+                           is_derived = True)
+      result.append(subproject)
+      result.extend(subproject.GetDerivedSubprojects())
+    return result
+
+
 ## Direct Git Commands ##
 
   def _RemoteFetch(self, name=None,
@@ -1382,14 +1557,14 @@
     tag_name = None
 
     def CheckForSha1():
-        try:
-          # if revision (sha or tag) is not present then following function
-          # throws an error.
-          self.bare_git.rev_parse('--verify', '%s^0' % self.revisionExpr)
-          return True
-        except GitError:
-          # There is no such persistent revision. We have to fetch it.
-          return False
+      try:
+        # if revision (sha or tag) is not present then following function
+        # throws an error.
+        self.bare_git.rev_parse('--verify', '%s^0' % self.revisionExpr)
+        return True
+      except GitError:
+        # There is no such persistent revision. We have to fetch it.
+        return False
 
     if current_branch_only:
       if ID_RE.match(self.revisionExpr) is not None:
@@ -1571,6 +1746,9 @@
         os.remove(tmpPath)
     if 'http_proxy' in os.environ and 'darwin' == sys.platform:
       cmd += ['--proxy', os.environ['http_proxy']]
+    cookiefile = GitConfig.ForUser().GetString('http.cookiefile')
+    if cookiefile:
+      cmd += ['--cookie', cookiefile]
     cmd += [srcUrl]
 
     if IsTrace():
@@ -1588,7 +1766,8 @@
       # returned another error with the HTTP error code being 400 or above.
       # This return code only appears if -f, --fail is used.
       if not quiet:
-        print >> sys.stderr, "Server does not provide clone.bundle; ignoring."
+        print("Server does not provide clone.bundle; ignoring.",
+              file=sys.stderr)
       return False
 
     if os.path.exists(tmpPath):
@@ -1836,7 +2015,8 @@
       if p.Wait() == 0:
         out = p.stdout
         if out:
-          return out[:-1].split("\0")
+          return out[:-1].split('\0')  # pylint: disable=W1401
+                                       # Backslash is not anomalous
       return []
 
     def DiffZ(self, name, *args):
@@ -1852,7 +2032,7 @@
         out = p.process.stdout.read()
         r = {}
         if out:
-          out = iter(out[:-1].split('\0'))
+          out = iter(out[:-1].split('\0'))  # pylint: disable=W1401
           while out:
             try:
               info = out.next()
@@ -1879,7 +2059,7 @@
                     self.level = self.level[1:]
 
             info = info[1:].split(' ')
-            info =_Info(path, *info)
+            info = _Info(path, *info)
             if info.status in ('R', 'C'):
               info.src_path = info.path
               info.path = out.next()
@@ -1893,7 +2073,10 @@
         path = os.path.join(self._project.gitdir, HEAD)
       else:
         path = os.path.join(self._project.worktree, '.git', HEAD)
-      fd = open(path, 'rb')
+      try:
+        fd = open(path, 'rb')
+      except IOError:
+        raise NoManifestException(path)
       try:
         line = fd.read()
       finally:
@@ -1988,6 +2171,9 @@
           raise TypeError('%s() got an unexpected keyword argument %r'
                           % (name, k))
         if config is not None:
+          if not git_require((1, 7, 2)):
+            raise ValueError('cannot set config on command line for %s()'
+                             % name)
           for k, v in config.iteritems():
             cmdv.append('-c')
             cmdv.append('%s=%s' % (k, v))
diff --git a/repo b/repo
index 70f4157..6b374f7 100755
--- a/repo
+++ b/repo
@@ -1,9 +1,10 @@
-#!/bin/sh
+#!/usr/bin/env python
 
 ## repo default configuration
 ##
-REPO_URL='https://gerrit.googlesource.com/git-repo'
-REPO_REV='stable'
+from __future__ import print_function
+REPO_URL = 'https://gerrit.googlesource.com/git-repo'
+REPO_REV = 'stable'
 
 # Copyright (C) 2008 Google Inc.
 #
@@ -19,19 +20,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-magic='--calling-python-from-/bin/sh--'
-"""exec" python -E "$0" "$@" """#$magic"
-if __name__ == '__main__':
-  import sys
-  if sys.argv[-1] == '#%s' % magic:
-    del sys.argv[-1]
-del magic
-
 # increment this whenever we make important changes to this script
-VERSION = (1, 18)
+VERSION = (1, 19)
 
 # increment this if the MAINTAINER_KEYS block is modified
-KEYRING_VERSION = (1,1)
+KEYRING_VERSION = (1, 1)
 MAINTAINER_KEYS = """
 
      Repo Maintainer <repo@android.kernel.org>
@@ -110,7 +103,7 @@
 """
 
 GIT = 'git'                     # our git command
-MIN_GIT_VERSION = (1, 5, 4)     # minimum supported git version
+MIN_GIT_VERSION = (1, 7, 2)     # minimum supported git version
 repodir = '.repo'               # name of repo's private directory
 S_repo = 'repo'                 # special repo repository
 S_manifests = 'manifests'       # special manifest repository
@@ -120,9 +113,21 @@
 import optparse
 import os
 import re
+import stat
 import subprocess
 import sys
-import urllib2
+try:
+  import urllib2
+except ImportError:
+  # For python3
+  import urllib.request
+  import urllib.error
+else:
+  # For python2
+  import imp
+  urllib = imp.new_module('urllib')
+  urllib.request = urllib2
+  urllib.error = urllib2
 
 home_dot_repo = os.path.expanduser('~/.repoconfig')
 gpg_dir = os.path.join(home_dot_repo, 'gnupg')
@@ -149,7 +154,8 @@
                  help='initial manifest file', metavar='NAME.xml')
 group.add_option('--mirror',
                  dest='mirror', action='store_true',
-                 help='mirror the forrest')
+                 help='create a replica of the remote repositories '
+                      'rather than a client working directory')
 group.add_option('--reference',
                  dest='reference',
                  help='location of mirror directory', metavar='DIR')
@@ -211,17 +217,16 @@
   if branch.startswith('refs/heads/'):
     branch = branch[len('refs/heads/'):]
   if branch.startswith('refs/'):
-    print >>sys.stderr, "fatal: invalid branch name '%s'" % branch
+    print("fatal: invalid branch name '%s'" % branch, file=sys.stderr)
     raise CloneFailure()
 
   if not os.path.isdir(repodir):
     try:
       os.mkdir(repodir)
     except OSError as e:
-      print >>sys.stderr, \
-            'fatal: cannot make %s directory: %s' % (
-            repodir, e.strerror)
-      # Don't faise CloneFailure; that would delete the
+      print('fatal: cannot make %s directory: %s'
+            % (repodir, e.strerror), file=sys.stderr)
+      # Don't raise CloneFailure; that would delete the
       # name. Instead exit immediately.
       #
       sys.exit(1)
@@ -244,8 +249,8 @@
     _Checkout(dst, branch, rev, opt.quiet)
   except CloneFailure:
     if opt.quiet:
-      print >>sys.stderr, \
-        'fatal: repo init failed; run without --quiet to see why'
+      print('fatal: repo init failed; run without --quiet to see why',
+            file=sys.stderr)
     raise
 
 
@@ -254,12 +259,12 @@
   try:
     proc = subprocess.Popen(cmd, stdout=subprocess.PIPE)
   except OSError as e:
-    print >>sys.stderr
-    print >>sys.stderr, "fatal: '%s' is not available" % GIT
-    print >>sys.stderr, 'fatal: %s' % e
-    print >>sys.stderr
-    print >>sys.stderr, 'Please make sure %s is installed'\
-                        ' and in your path.' % GIT
+    print(file=sys.stderr)
+    print("fatal: '%s' is not available" % GIT, file=sys.stderr)
+    print('fatal: %s' % e, file=sys.stderr)
+    print(file=sys.stderr)
+    print('Please make sure %s is installed and in your path.' % GIT,
+          file=sys.stderr)
     raise CloneFailure()
 
   ver_str = proc.stdout.read().strip()
@@ -267,14 +272,14 @@
   proc.wait()
 
   if not ver_str.startswith('git version '):
-    print >>sys.stderr, 'error: "%s" unsupported' % ver_str
+    print('error: "%s" unsupported' % ver_str, file=sys.stderr)
     raise CloneFailure()
 
   ver_str = ver_str[len('git version '):].strip()
-  ver_act = tuple(map(lambda x: int(x), ver_str.split('.')[0:3]))
+  ver_act = tuple(map(int, ver_str.split('.')[0:3]))
   if ver_act < MIN_GIT_VERSION:
-    need = '.'.join(map(lambda x: str(x), MIN_GIT_VERSION))
-    print >>sys.stderr, 'fatal: git %s or later required' % need
+    need = '.'.join(map(str, MIN_GIT_VERSION))
+    print('fatal: git %s or later required' % need, file=sys.stderr)
     raise CloneFailure()
 
 
@@ -290,7 +295,7 @@
   if not kv:
     return True
 
-  kv = tuple(map(lambda x: int(x), kv.split('.')))
+  kv = tuple(map(int, kv.split('.')))
   if kv < KEYRING_VERSION:
     return True
   return False
@@ -301,18 +306,16 @@
     try:
       os.mkdir(home_dot_repo)
     except OSError as e:
-      print >>sys.stderr, \
-            'fatal: cannot make %s directory: %s' % (
-            home_dot_repo, e.strerror)
+      print('fatal: cannot make %s directory: %s'
+            % (home_dot_repo, e.strerror), file=sys.stderr)
       sys.exit(1)
 
   if not os.path.isdir(gpg_dir):
     try:
-      os.mkdir(gpg_dir, 0700)
+      os.mkdir(gpg_dir, stat.S_IRWXU)
     except OSError as e:
-      print >>sys.stderr, \
-            'fatal: cannot make %s directory: %s' % (
-            gpg_dir, e.strerror)
+      print('fatal: cannot make %s directory: %s' % (gpg_dir, e.strerror),
+            file=sys.stderr)
       sys.exit(1)
 
   env = os.environ.copy()
@@ -325,21 +328,21 @@
                             stdin = subprocess.PIPE)
   except OSError as e:
     if not quiet:
-      print >>sys.stderr, 'warning: gpg (GnuPG) is not available.'
-      print >>sys.stderr, 'warning: Installing it is strongly encouraged.'
-      print >>sys.stderr
+      print('warning: gpg (GnuPG) is not available.', file=sys.stderr)
+      print('warning: Installing it is strongly encouraged.', file=sys.stderr)
+      print(file=sys.stderr)
     return False
 
   proc.stdin.write(MAINTAINER_KEYS)
   proc.stdin.close()
 
   if proc.wait() != 0:
-    print >>sys.stderr, 'fatal: registering repo maintainer keys failed'
+    print('fatal: registering repo maintainer keys failed', file=sys.stderr)
     sys.exit(1)
-  print
+  print()
 
   fd = open(os.path.join(home_dot_repo, 'keyring-version'), 'w')
-  fd.write('.'.join(map(lambda x: str(x), KEYRING_VERSION)) + '\n')
+  fd.write('.'.join(map(str, KEYRING_VERSION)) + '\n')
   fd.close()
   return True
 
@@ -355,7 +358,7 @@
 def _InitHttp():
   handlers = []
 
-  mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
+  mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
   try:
     import netrc
     n = netrc.netrc()
@@ -365,20 +368,20 @@
       mgr.add_password(p[1], 'https://%s/' % host, p[0], p[2])
   except:
     pass
-  handlers.append(urllib2.HTTPBasicAuthHandler(mgr))
-  handlers.append(urllib2.HTTPDigestAuthHandler(mgr))
+  handlers.append(urllib.request.HTTPBasicAuthHandler(mgr))
+  handlers.append(urllib.request.HTTPDigestAuthHandler(mgr))
 
   if 'http_proxy' in os.environ:
     url = os.environ['http_proxy']
-    handlers.append(urllib2.ProxyHandler({'http': url, 'https': url}))
+    handlers.append(urllib.request.ProxyHandler({'http': url, 'https': url}))
   if 'REPO_CURL_VERBOSE' in os.environ:
-    handlers.append(urllib2.HTTPHandler(debuglevel=1))
-    handlers.append(urllib2.HTTPSHandler(debuglevel=1))
-  urllib2.install_opener(urllib2.build_opener(*handlers))
+    handlers.append(urllib.request.HTTPHandler(debuglevel=1))
+    handlers.append(urllib.request.HTTPSHandler(debuglevel=1))
+  urllib.request.install_opener(urllib.request.build_opener(*handlers))
 
 def _Fetch(url, local, src, quiet):
   if not quiet:
-    print >>sys.stderr, 'Get %s' % url
+    print('Get %s' % url, file=sys.stderr)
 
   cmd = [GIT, 'fetch']
   if quiet:
@@ -423,20 +426,20 @@
   dest = open(os.path.join(local, '.git', 'clone.bundle'), 'w+b')
   try:
     try:
-      r = urllib2.urlopen(url)
-    except urllib2.HTTPError as e:
-      if e.code == 404:
+      r = urllib.request.urlopen(url)
+    except urllib.error.HTTPError as e:
+      if e.code in [403, 404]:
         return False
-      print >>sys.stderr, 'fatal: Cannot get %s' % url
-      print >>sys.stderr, 'fatal: HTTP error %s' % e.code
+      print('fatal: Cannot get %s' % url, file=sys.stderr)
+      print('fatal: HTTP error %s' % e.code, file=sys.stderr)
       raise CloneFailure()
-    except urllib2.URLError as e:
-      print >>sys.stderr, 'fatal: Cannot get %s' % url
-      print >>sys.stderr, 'fatal: error %s' % e.reason
+    except urllib.error.URLError as e:
+      print('fatal: Cannot get %s' % url, file=sys.stderr)
+      print('fatal: error %s' % e.reason, file=sys.stderr)
       raise CloneFailure()
     try:
       if not quiet:
-        print >>sys.stderr, 'Get %s' % url
+        print('Get %s' % url, file=sys.stderr)
       while True:
         buf = r.read(8192)
         if buf == '':
@@ -460,24 +463,23 @@
   try:
     os.mkdir(local)
   except OSError as e:
-    print >>sys.stderr, \
-          'fatal: cannot make %s directory: %s' \
-          % (local, e.strerror)
+    print('fatal: cannot make %s directory: %s' % (local, e.strerror),
+          file=sys.stderr)
     raise CloneFailure()
 
   cmd = [GIT, 'init', '--quiet']
   try:
     proc = subprocess.Popen(cmd, cwd = local)
   except OSError as e:
-    print >>sys.stderr
-    print >>sys.stderr, "fatal: '%s' is not available" % GIT
-    print >>sys.stderr, 'fatal: %s' % e
-    print >>sys.stderr
-    print >>sys.stderr, 'Please make sure %s is installed'\
-                        ' and in your path.' % GIT
+    print(file=sys.stderr)
+    print("fatal: '%s' is not available" % GIT, file=sys.stderr)
+    print('fatal: %s' % e, file=sys.stderr)
+    print(file=sys.stderr)
+    print('Please make sure %s is installed and in your path.' % GIT,
+          file=sys.stderr)
     raise CloneFailure()
   if proc.wait() != 0:
-    print >>sys.stderr, 'fatal: could not create %s' % local
+    print('fatal: could not create %s' % local, file=sys.stderr)
     raise CloneFailure()
 
   _InitHttp()
@@ -505,21 +507,18 @@
   proc.stderr.close()
 
   if proc.wait() != 0 or not cur:
-    print >>sys.stderr
-    print >>sys.stderr,\
-      "fatal: branch '%s' has not been signed" \
-      % branch
+    print(file=sys.stderr)
+    print("fatal: branch '%s' has not been signed" % branch, file=sys.stderr)
     raise CloneFailure()
 
   m = re.compile(r'^(.*)-[0-9]{1,}-g[0-9a-f]{1,}$').match(cur)
   if m:
     cur = m.group(1)
     if not quiet:
-      print >>sys.stderr
-      print >>sys.stderr, \
-        "info: Ignoring branch '%s'; using tagged release '%s'" \
-        % (branch, cur)
-      print >>sys.stderr
+      print(file=sys.stderr)
+      print("info: Ignoring branch '%s'; using tagged release '%s'"
+            % (branch, cur), file=sys.stderr)
+      print(file=sys.stderr)
 
   env = os.environ.copy()
   env['GNUPGHOME'] = gpg_dir.encode()
@@ -537,10 +536,10 @@
   proc.stderr.close()
 
   if proc.wait() != 0:
-    print >>sys.stderr
-    print >>sys.stderr, out
-    print >>sys.stderr, err
-    print >>sys.stderr
+    print(file=sys.stderr)
+    print(out, file=sys.stderr)
+    print(err, file=sys.stderr)
+    print(file=sys.stderr)
     raise CloneFailure()
   return '%s^0' % cur
 
@@ -594,7 +593,7 @@
   opt = _Options()
   arg = []
 
-  for i in xrange(0, len(args)):
+  for i in range(len(args)):
     a = args[i]
     if a == '-h' or a == '--help':
       opt.help = True
@@ -607,7 +606,7 @@
 
 
 def _Usage():
-  print >>sys.stderr,\
+  print(
 """usage: repo COMMAND [ARGS]
 
 repo is not yet installed.  Use "repo init" to install it here.
@@ -618,7 +617,7 @@
   help      Display detailed help on a command
 
 For access to the full online help, install repo ("repo init").
-"""
+""", file=sys.stderr)
   sys.exit(1)
 
 
@@ -628,25 +627,23 @@
       init_optparse.print_help()
       sys.exit(0)
     else:
-      print >>sys.stderr,\
-      "error: '%s' is not a bootstrap command.\n"\
-      '        For access to online help, install repo ("repo init").'\
-      % args[0]
+      print("error: '%s' is not a bootstrap command.\n"
+            '        For access to online help, install repo ("repo init").'
+            % args[0], file=sys.stderr)
   else:
     _Usage()
   sys.exit(1)
 
 
 def _NotInstalled():
-  print >>sys.stderr,\
-'error: repo is not installed.  Use "repo init" to install it here.'
+  print('error: repo is not installed.  Use "repo init" to install it here.',
+        file=sys.stderr)
   sys.exit(1)
 
 
 def _NoCommands(cmd):
-  print >>sys.stderr,\
-"""error: command '%s' requires repo to be installed first.
-       Use "repo init" to install it here.""" % cmd
+  print("""error: command '%s' requires repo to be installed first.
+        Use "repo init" to install it here.""" % cmd, file=sys.stderr)
   sys.exit(1)
 
 
@@ -683,7 +680,7 @@
   proc.stderr.close()
 
   if proc.wait() != 0:
-    print >>sys.stderr, 'fatal: %s has no current branch' % gitdir
+    print('fatal: %s has no current branch' % gitdir, file=sys.stderr)
     sys.exit(1)
 
 
@@ -721,7 +718,7 @@
   if my_main:
     repo_main = my_main
 
-  ver_str = '.'.join(map(lambda x: str(x), VERSION))
+  ver_str = '.'.join(map(str, VERSION))
   me = [repo_main,
         '--repo-dir=%s' % rel_repo_dir,
         '--wrapper-version=%s' % ver_str,
@@ -732,8 +729,8 @@
   try:
     os.execv(repo_main, me)
   except OSError as e:
-    print >>sys.stderr, "fatal: unable to start %s" % repo_main
-    print >>sys.stderr, "fatal: %s" % e
+    print("fatal: unable to start %s" % repo_main, file=sys.stderr)
+    print("fatal: %s" % e, file=sys.stderr)
     sys.exit(148)
 
 
diff --git a/subcmds/abandon.py b/subcmds/abandon.py
index e17ab2b..b94ccdd 100644
--- a/subcmds/abandon.py
+++ b/subcmds/abandon.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from command import Command
 from git_command import git
@@ -36,7 +37,7 @@
 
     nb = args[0]
     if not git.check_ref_format('heads/%s' % nb):
-      print >>sys.stderr, "error: '%s' is not a valid name" % nb
+      print("error: '%s' is not a valid name" % nb, file=sys.stderr)
       sys.exit(1)
 
     nb = args[0]
@@ -58,13 +59,13 @@
 
     if err:
       for p in err:
-        print >>sys.stderr,\
-          "error: %s/: cannot abandon %s" \
-          % (p.relpath, nb)
+        print("error: %s/: cannot abandon %s" % (p.relpath, nb),
+              file=sys.stderr)
       sys.exit(1)
     elif not success:
-      print >>sys.stderr, 'error: no project has branch %s' % nb
+      print('error: no project has branch %s' % nb, file=sys.stderr)
       sys.exit(1)
     else:
-      print >>sys.stderr, 'Abandoned in %d project(s):\n  %s' % (
-            len(success), '\n  '.join(p.relpath for p in success))
+      print('Abandoned in %d project(s):\n  %s'
+            % (len(success), '\n  '.join(p.relpath for p in success)),
+            file=sys.stderr)
diff --git a/subcmds/branches.py b/subcmds/branches.py
index a7ba3d6..06d45ab 100644
--- a/subcmds/branches.py
+++ b/subcmds/branches.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from color import Coloring
 from command import Command
@@ -107,7 +108,7 @@
     names.sort()
 
     if not names:
-      print >>sys.stderr, '   (no branches)'
+      print('   (no branches)', file=sys.stderr)
       return
 
     width = 25
diff --git a/subcmds/checkout.py b/subcmds/checkout.py
index bfbe992..cbbca10 100644
--- a/subcmds/checkout.py
+++ b/subcmds/checkout.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from command import Command
 from progress import Progress
@@ -55,10 +56,9 @@
 
     if err:
       for p in err:
-        print >>sys.stderr,\
-          "error: %s/: cannot checkout %s" \
-          % (p.relpath, nb)
+        print("error: %s/: cannot checkout %s" % (p.relpath, nb),
+              file=sys.stderr)
       sys.exit(1)
     elif not success:
-      print >>sys.stderr, 'error: no project has branch %s' % nb
+      print('error: no project has branch %s' % nb, file=sys.stderr)
       sys.exit(1)
diff --git a/subcmds/cherry_pick.py b/subcmds/cherry_pick.py
index 7a6d4c2..01b97e0 100644
--- a/subcmds/cherry_pick.py
+++ b/subcmds/cherry_pick.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import re
 import sys
 from command import Command
@@ -46,13 +47,13 @@
                    capture_stdout = True,
                    capture_stderr = True)
     if p.Wait() != 0:
-      print >>sys.stderr, p.stderr
+      print(p.stderr, file=sys.stderr)
       sys.exit(1)
     sha1 = p.stdout.strip()
 
     p = GitCommand(None, ['cat-file', 'commit', sha1], capture_stdout=True)
     if p.Wait() != 0:
-      print >>sys.stderr, "error: Failed to retrieve old commit message"
+      print("error: Failed to retrieve old commit message", file=sys.stderr)
       sys.exit(1)
     old_msg = self._StripHeader(p.stdout)
 
@@ -62,8 +63,8 @@
                    capture_stderr = True)
     status = p.Wait()
 
-    print >>sys.stdout, p.stdout
-    print >>sys.stderr, p.stderr
+    print(p.stdout, file=sys.stdout)
+    print(p.stderr, file=sys.stderr)
 
     if status == 0:
       # The cherry-pick was applied correctly. We just need to edit the
@@ -76,16 +77,14 @@
                      capture_stderr = True)
       p.stdin.write(new_msg)
       if p.Wait() != 0:
-        print >>sys.stderr, "error: Failed to update commit message"
+        print("error: Failed to update commit message", file=sys.stderr)
         sys.exit(1)
 
     else:
-      print >>sys.stderr, """\
-NOTE: When committing (please see above) and editing the commit message,
-please remove the old Change-Id-line and add:
-"""
-      print >>sys.stderr, self._GetReference(sha1)
-      print >>sys.stderr
+      print('NOTE: When committing (please see above) and editing the commit'
+            'message, please remove the old Change-Id-line and add:')
+      print(self._GetReference(sha1), file=sys.stderr)
+      print(file=sys.stderr)
 
   def _IsChangeId(self, line):
     return CHANGE_ID_RE.match(line)
diff --git a/subcmds/download.py b/subcmds/download.py
index 0abe90d..471e88b 100644
--- a/subcmds/download.py
+++ b/subcmds/download.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import re
 import sys
 
@@ -32,13 +33,13 @@
 """
 
   def _Options(self, p):
-    p.add_option('-c','--cherry-pick',
+    p.add_option('-c', '--cherry-pick',
                  dest='cherrypick', action='store_true',
                  help="cherry-pick instead of checkout")
-    p.add_option('-r','--revert',
+    p.add_option('-r', '--revert',
                  dest='revert', action='store_true',
                  help="revert instead of checkout")
-    p.add_option('-f','--ff-only',
+    p.add_option('-f', '--ff-only',
                  dest='ffonly', action='store_true',
                  help="force fast-forward merge")
 
@@ -68,23 +69,23 @@
     for project, change_id, ps_id in self._ParseChangeIds(args):
       dl = project.DownloadPatchSet(change_id, ps_id)
       if not dl:
-        print >>sys.stderr, \
-          '[%s] change %d/%d not found' \
-          % (project.name, change_id, ps_id)
+        print('[%s] change %d/%d not found'
+              % (project.name, change_id, ps_id),
+              file=sys.stderr)
         sys.exit(1)
 
       if not opt.revert and not dl.commits:
-        print >>sys.stderr, \
-          '[%s] change %d/%d has already been merged' \
-          % (project.name, change_id, ps_id)
+        print('[%s] change %d/%d has already been merged'
+              % (project.name, change_id, ps_id),
+              file=sys.stderr)
         continue
 
       if len(dl.commits) > 1:
-        print >>sys.stderr, \
-          '[%s] %d/%d depends on %d unmerged changes:' \
-          % (project.name, change_id, ps_id, len(dl.commits))
+        print('[%s] %d/%d depends on %d unmerged changes:' \
+              % (project.name, change_id, ps_id, len(dl.commits)),
+              file=sys.stderr)
         for c in dl.commits:
-          print >>sys.stderr, '  %s' % (c)
+          print('  %s' % (c), file=sys.stderr)
       if opt.cherrypick:
         project._CherryPick(dl.commit)
       elif opt.revert:
diff --git a/subcmds/forall.py b/subcmds/forall.py
index b633b7d..4c1c9ff 100644
--- a/subcmds/forall.py
+++ b/subcmds/forall.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import fcntl
 import re
 import os
@@ -92,6 +93,9 @@
 
 Unless -p is used, stdin, stdout, stderr are inherited from the
 terminal and are not redirected.
+
+If -e is used, when a command exits unsuccessfully, '%prog' will abort
+without iterating through the remaining projects.
 """
 
   def _Options(self, p):
@@ -104,6 +108,9 @@
                  dest='command',
                  action='callback',
                  callback=cmd)
+    p.add_option('-e', '--abort-on-errors',
+                 dest='abort_on_errors', action='store_true',
+                 help='Abort if a command exits unsuccessfully')
 
     g = p.add_option_group('Output')
     g.add_option('-p',
@@ -183,7 +190,7 @@
       if not os.path.exists(cwd):
         if (opt.project_header and opt.verbose) \
         or not opt.project_header:
-          print >>sys.stderr, 'skipping %s/' % project.relpath
+          print('skipping %s/' % project.relpath, file=sys.stderr)
         continue
 
       if opt.project_header:
@@ -254,7 +261,12 @@
             s.dest.flush()
 
       r = p.wait()
-      if r != 0 and r != rc:
-        rc = r
+      if r != 0:
+        if r != rc:
+          rc = r
+        if opt.abort_on_errors:
+          print("error: %s: Aborting due to previous error" % project.relpath,
+                file=sys.stderr)
+          sys.exit(r)
     if rc != 0:
       sys.exit(rc)
diff --git a/subcmds/grep.py b/subcmds/grep.py
index 0dc8f9f..dd391cf 100644
--- a/subcmds/grep.py
+++ b/subcmds/grep.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from color import Coloring
 from command import PagedCommand
@@ -51,7 +52,7 @@
 
 Look for a line that has '#define' and either 'MAX_PATH or 'PATH_MAX':
 
-  repo grep -e '#define' --and -\( -e MAX_PATH -e PATH_MAX \)
+  repo grep -e '#define' --and -\\( -e MAX_PATH -e PATH_MAX \\)
 
 Look for a line that has 'NODE' or 'Unexpected' in files that
 contain a line that matches both expressions:
@@ -84,7 +85,7 @@
     g.add_option('--cached',
                  action='callback', callback=carry,
                  help='Search the index, instead of the work tree')
-    g.add_option('-r','--revision',
+    g.add_option('-r', '--revision',
                  dest='revision', action='append', metavar='TREEish',
                  help='Search TREEish, instead of the work tree')
 
@@ -96,7 +97,7 @@
     g.add_option('-i', '--ignore-case',
                  action='callback', callback=carry,
                  help='Ignore case differences')
-    g.add_option('-a','--text',
+    g.add_option('-a', '--text',
                  action='callback', callback=carry,
                  help="Process binary files as if they were text")
     g.add_option('-I',
@@ -125,7 +126,7 @@
     g.add_option('--and', '--or', '--not',
                  action='callback', callback=carry,
                  help='Boolean operators to combine patterns')
-    g.add_option('-(','-)',
+    g.add_option('-(', '-)',
                  action='callback', callback=carry,
                  help='Boolean operator grouping')
 
@@ -145,10 +146,10 @@
                  action='callback', callback=carry,
                  metavar='CONTEXT', type='str',
                  help='Show CONTEXT lines after match')
-    g.add_option('-l','--name-only','--files-with-matches',
+    g.add_option('-l', '--name-only', '--files-with-matches',
                  action='callback', callback=carry,
                  help='Show only file names containing matching lines')
-    g.add_option('-L','--files-without-match',
+    g.add_option('-L', '--files-without-match',
                  action='callback', callback=carry,
                  help='Show only file names not containing matching lines')
 
@@ -157,9 +158,9 @@
     out = GrepColoring(self.manifest.manifestProject.config)
 
     cmd_argv = ['grep']
-    if out.is_on and git_require((1,6,3)):
+    if out.is_on and git_require((1, 6, 3)):
       cmd_argv.append('--color')
-    cmd_argv.extend(getattr(opt,'cmd_argv',[]))
+    cmd_argv.extend(getattr(opt, 'cmd_argv', []))
 
     if '-e' not in cmd_argv:
       if not args:
@@ -178,8 +179,7 @@
     have_rev = False
     if opt.revision:
       if '--cached' in cmd_argv:
-        print >>sys.stderr,\
-          'fatal: cannot combine --cached and --revision'
+        print('fatal: cannot combine --cached and --revision', file=sys.stderr)
         sys.exit(1)
       have_rev = True
       cmd_argv.extend(opt.revision)
@@ -230,13 +230,13 @@
           out.nl()
       else:
         for line in r:
-          print line
+          print(line)
 
     if have_match:
       sys.exit(0)
     elif have_rev and bad_rev:
       for r in opt.revision:
-        print >>sys.stderr, "error: can't search revision %s" % r
+        print("error: can't search revision %s" % r, file=sys.stderr)
       sys.exit(1)
     else:
       sys.exit(1)
diff --git a/subcmds/help.py b/subcmds/help.py
index 375d04d..15aab7f 100644
--- a/subcmds/help.py
+++ b/subcmds/help.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import re
 import sys
 from formatter import AbstractFormatter, DumbWriter
@@ -31,10 +32,8 @@
 """
 
   def _PrintAllCommands(self):
-    print 'usage: repo COMMAND [ARGS]'
-    print """
-The complete list of recognized repo commands are:
-"""
+    print('usage: repo COMMAND [ARGS]')
+    print('The complete list of recognized repo commands are:')
     commandNames = self.commands.keys()
     commandNames.sort()
 
@@ -49,17 +48,14 @@
         summary = command.helpSummary.strip()
       except AttributeError:
         summary = ''
-      print fmt % (name, summary)
-    print """
-See 'repo help <command>' for more information on a specific command.
-"""
+      print(fmt % (name, summary))
+    print("See 'repo help <command>' for more information on a"
+          'specific command.')
 
   def _PrintCommonCommands(self):
-    print 'usage: repo COMMAND [ARGS]'
-    print """
-The most commonly used repo commands are:
-"""
-    commandNames = [name 
+    print('usage: repo COMMAND [ARGS]')
+    print('The most commonly used repo commands are:')
+    commandNames = [name
                     for name in self.commands.keys()
                     if self.commands[name].common]
     commandNames.sort()
@@ -75,11 +71,10 @@
         summary = command.helpSummary.strip()
       except AttributeError:
         summary = ''
-      print fmt % (name, summary)
-    print """
-See 'repo help <command>' for more information on a specific command.
-See 'repo help --all' for a complete list of recognized commands.
-"""
+      print(fmt % (name, summary))
+    print(
+"See 'repo help <command>' for more information on a specific command.\n"
+"See 'repo help --all' for a complete list of recognized commands.")
 
   def _PrintCommandHelp(self, cmd):
     class _Out(Coloring):
@@ -131,7 +126,7 @@
 
             p('%s', title)
             self.nl()
-            p('%s', ''.ljust(len(title),section_type[0]))
+            p('%s', ''.ljust(len(title), section_type[0]))
             self.nl()
             continue
 
@@ -162,7 +157,7 @@
       try:
         cmd = self.commands[name]
       except KeyError:
-        print >>sys.stderr, "repo: '%s' is not a repo command." % name
+        print("repo: '%s' is not a repo command." % name, file=sys.stderr)
         sys.exit(1)
 
       cmd.manifest = self.manifest
diff --git a/subcmds/info.py b/subcmds/info.py
new file mode 100644
index 0000000..a6eba88
--- /dev/null
+++ b/subcmds/info.py
@@ -0,0 +1,195 @@
+#
+# Copyright (C) 2012 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from command import PagedCommand
+from color import Coloring
+from error import NoSuchProjectError
+from git_refs import R_M
+
+class _Coloring(Coloring):
+  def __init__(self, config):
+    Coloring.__init__(self, config, "status")
+
+class Info(PagedCommand):
+  common = True
+  helpSummary = "Get info on the manifest branch, current branch or unmerged branches"
+  helpUsage = "%prog [-dl] [-o [-b]] [<project>...]"
+
+  def _Options(self, p, show_smart=True):
+    p.add_option('-d', '--diff',
+                 dest='all', action='store_true',
+                 help="show full info and commit diff including remote branches")
+    p.add_option('-o', '--overview',
+                 dest='overview', action='store_true',
+                 help='show overview of all local commits')
+    p.add_option('-b', '--current-branch',
+                 dest="current_branch", action="store_true",
+                 help="consider only checked out branches")
+    p.add_option('-l', '--local-only',
+                 dest="local", action="store_true",
+                 help="Disable all remote operations")
+
+
+  def Execute(self, opt, args):
+    self.out = _Coloring(self.manifest.globalConfig)
+    self.heading = self.out.printer('heading', attr = 'bold')
+    self.headtext = self.out.printer('headtext', fg = 'yellow')
+    self.redtext = self.out.printer('redtext', fg = 'red')
+    self.sha = self.out.printer("sha", fg = 'yellow')
+    self.text = self.out.printer('text')
+    self.dimtext = self.out.printer('dimtext', attr = 'dim')
+
+    self.opt = opt
+
+    mergeBranch = self.manifest.manifestProject.config.GetBranch("default").merge
+
+    self.heading("Manifest branch: ")
+    self.headtext(self.manifest.default.revisionExpr)
+    self.out.nl()
+    self.heading("Manifest merge branch: ")
+    self.headtext(mergeBranch)
+    self.out.nl()
+
+    self.printSeparator()
+
+    if not opt.overview:
+      self.printDiffInfo(args)
+    else:
+      self.printCommitOverview(args)
+
+  def printSeparator(self):
+    self.text("----------------------------")
+    self.out.nl()
+
+  def printDiffInfo(self, args):
+    try:
+      projs = self.GetProjects(args)
+    except NoSuchProjectError:
+      return
+
+    for p in projs:
+      self.heading("Project: ")
+      self.headtext(p.name)
+      self.out.nl()
+
+      self.heading("Mount path: ")
+      self.headtext(p.worktree)
+      self.out.nl()
+
+      self.heading("Current revision: ")
+      self.headtext(p.revisionExpr)
+      self.out.nl()
+
+      localBranches = p.GetBranches().keys()
+      self.heading("Local Branches: ")
+      self.redtext(str(len(localBranches)))
+      if len(localBranches) > 0:
+        self.text(" [")
+        self.text(", ".join(localBranches))
+        self.text("]")
+      self.out.nl()
+
+      if self.opt.all:
+        self.findRemoteLocalDiff(p)
+
+      self.printSeparator()
+
+  def findRemoteLocalDiff(self, project):
+    #Fetch all the latest commits
+    if not self.opt.local:
+      project.Sync_NetworkHalf(quiet=True, current_branch_only=True)
+
+    logTarget = R_M + self.manifest.manifestProject.config.GetBranch("default").merge
+
+    bareTmp = project.bare_git._bare
+    project.bare_git._bare = False
+    localCommits = project.bare_git.rev_list(
+        '--abbrev=8',
+        '--abbrev-commit',
+        '--pretty=oneline',
+        logTarget + "..",
+        '--')
+
+    originCommits = project.bare_git.rev_list(
+        '--abbrev=8',
+        '--abbrev-commit',
+        '--pretty=oneline',
+        ".." + logTarget,
+        '--')
+    project.bare_git._bare = bareTmp
+
+    self.heading("Local Commits: ")
+    self.redtext(str(len(localCommits)))
+    self.dimtext(" (on current branch)")
+    self.out.nl()
+
+    for c in localCommits:
+      split = c.split()
+      self.sha(split[0] + " ")
+      self.text(" ".join(split[1:]))
+      self.out.nl()
+
+    self.printSeparator()
+
+    self.heading("Remote Commits: ")
+    self.redtext(str(len(originCommits)))
+    self.out.nl()
+
+    for c in originCommits:
+      split = c.split()
+      self.sha(split[0] + " ")
+      self.text(" ".join(split[1:]))
+      self.out.nl()
+
+  def printCommitOverview(self, args):
+    all_branches = []
+    for project in self.GetProjects(args):
+      br = [project.GetUploadableBranch(x)
+            for x in project.GetBranches().keys()]
+      br = [x for x in br if x]
+      if self.opt.current_branch:
+        br = [x for x in br if x.name == project.CurrentBranch]
+      all_branches.extend(br)
+
+    if not all_branches:
+      return
+
+    self.out.nl()
+    self.heading('Projects Overview')
+    project = None
+
+    for branch in all_branches:
+      if project != branch.project:
+        project = branch.project
+        self.out.nl()
+        self.headtext(project.relpath)
+        self.out.nl()
+
+      commits = branch.commits
+      date = branch.date
+      self.text('%s %-33s (%2d commit%s, %s)' % (
+        branch.name == project.CurrentBranch and '*' or ' ',
+        branch.name,
+        len(commits),
+        len(commits) != 1 and 's' or '',
+        date))
+      self.out.nl()
+
+      for commit in commits:
+        split = commit.split()
+        self.text('{0:38}{1} '.format('','-'))
+        self.sha(split[0] + " ")
+        self.text(" ".join(split[1:]))
+        self.out.nl()
diff --git a/subcmds/init.py b/subcmds/init.py
index b6b9807..1131260 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import platform
 import re
@@ -117,18 +118,22 @@
                  dest='config_name', action="store_true", default=False,
                  help='Always prompt for name/e-mail')
 
+  def _RegisteredEnvironmentOptions(self):
+    return {'REPO_MANIFEST_URL': 'manifest_url',
+            'REPO_MIRROR_LOCATION': 'reference'}
+
   def _SyncManifest(self, opt):
     m = self.manifest.manifestProject
     is_new = not m.Exists
 
     if is_new:
       if not opt.manifest_url:
-        print >>sys.stderr, 'fatal: manifest url (-u) is required.'
+        print('fatal: manifest url (-u) is required.', file=sys.stderr)
         sys.exit(1)
 
       if not opt.quiet:
-        print >>sys.stderr, 'Get %s' \
-          % GitConfig.ForUser().UrlInsteadOf(opt.manifest_url)
+        print('Get %s' % GitConfig.ForUser().UrlInsteadOf(opt.manifest_url),
+              file=sys.stderr)
       m._InitGitDir()
 
       if opt.manifest_branch:
@@ -147,7 +152,7 @@
       r.ResetFetch()
       r.Save()
 
-    groups = re.split('[,\s]+', opt.groups)
+    groups = re.split(r'[,\s]+', opt.groups)
     all_platforms = ['linux', 'darwin']
     platformize = lambda x: 'platform-' + x
     if opt.platform == 'auto':
@@ -159,7 +164,7 @@
     elif opt.platform in all_platforms:
       groups.extend(platformize(opt.platform))
     elif opt.platform != 'none':
-      print >>sys.stderr, 'fatal: invalid platform flag'
+      print('fatal: invalid platform flag', file=sys.stderr)
       sys.exit(1)
 
     groups = [x for x in groups if x]
@@ -175,12 +180,15 @@
       if is_new:
         m.config.SetString('repo.mirror', 'true')
       else:
-        print >>sys.stderr, 'fatal: --mirror not supported on existing client'
+        print('fatal: --mirror is only supported when initializing a new '
+              'workspace.', file=sys.stderr)
+        print('Either delete the .repo folder in this workspace, or initialize '
+              'in another location.', file=sys.stderr)
         sys.exit(1)
 
     if not m.Sync_NetworkHalf(is_new=is_new):
       r = m.GetRemote(m.remote.name)
-      print >>sys.stderr, 'fatal: cannot obtain manifest %s' % r.url
+      print('fatal: cannot obtain manifest %s' % r.url, file=sys.stderr)
 
       # Better delete the manifest git dir if we created it; otherwise next
       # time (when user fixes problems) we won't go through the "is_new" logic.
@@ -197,19 +205,19 @@
 
     if is_new or m.CurrentBranch is None:
       if not m.StartBranch('default'):
-        print >>sys.stderr, 'fatal: cannot create default in manifest'
+        print('fatal: cannot create default in manifest', file=sys.stderr)
         sys.exit(1)
 
   def _LinkManifest(self, name):
     if not name:
-      print >>sys.stderr, 'fatal: manifest name (-m) is required.'
+      print('fatal: manifest name (-m) is required.', file=sys.stderr)
       sys.exit(1)
 
     try:
       self.manifest.Link(name)
     except ManifestParseError as e:
-      print >>sys.stderr, "fatal: manifest '%s' not available" % name
-      print >>sys.stderr, 'fatal: %s' % str(e)
+      print("fatal: manifest '%s' not available" % name, file=sys.stderr)
+      print('fatal: %s' % str(e), file=sys.stderr)
       sys.exit(1)
 
   def _Prompt(self, prompt, value):
@@ -231,24 +239,24 @@
       mp.config.SetString('user.name', gc.GetString('user.name'))
       mp.config.SetString('user.email', gc.GetString('user.email'))
 
-    print ''
-    print 'Your identity is: %s <%s>' % (mp.config.GetString('user.name'),
-                                         mp.config.GetString('user.email'))
-    print 'If you want to change this, please re-run \'repo init\' with --config-name'
+    print()
+    print('Your identity is: %s <%s>' % (mp.config.GetString('user.name'),
+                                         mp.config.GetString('user.email')))
+    print('If you want to change this, please re-run \'repo init\' with --config-name')
     return False
 
   def _ConfigureUser(self):
     mp = self.manifest.manifestProject
 
     while True:
-      print ''
+      print()
       name  = self._Prompt('Your Name', mp.UserName)
       email = self._Prompt('Your Email', mp.UserEmail)
 
-      print ''
-      print 'Your identity is: %s <%s>' % (name, email)
+      print()
+      print('Your identity is: %s <%s>' % (name, email))
       sys.stdout.write('is this correct [y/N]? ')
-      a = sys.stdin.readline().strip()
+      a = sys.stdin.readline().strip().lower()
       if a in ('yes', 'y', 't', 'true'):
         break
 
@@ -274,17 +282,17 @@
         self._on = True
     out = _Test()
 
-    print ''
-    print "Testing colorized output (for 'repo diff', 'repo status'):"
+    print()
+    print("Testing colorized output (for 'repo diff', 'repo status'):")
 
-    for c in ['black','red','green','yellow','blue','magenta','cyan']:
+    for c in ['black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan']:
       out.write(' ')
       out.printer(fg=c)(' %-6s ', c)
     out.write(' ')
     out.printer(fg='white', bg='black')(' %s ' % 'white')
     out.nl()
 
-    for c in ['bold','dim','ul','reverse']:
+    for c in ['bold', 'dim', 'ul', 'reverse']:
       out.write(' ')
       out.printer(fg='black', attr=c)(' %-6s ', c)
     out.nl()
@@ -313,6 +321,23 @@
       # We store the depth in the main manifest project.
       self.manifest.manifestProject.config.SetString('repo.depth', depth)
 
+  def _DisplayResult(self):
+    if self.manifest.IsMirror:
+      init_type = 'mirror '
+    else:
+      init_type = ''
+
+    print()
+    print('repo %shas been initialized in %s'
+          % (init_type, self.manifest.topdir))
+
+    current_dir = os.getcwd()
+    if current_dir != self.manifest.topdir:
+      print('If this is not the directory in which you want to initialize '
+            'repo, please run:')
+      print('   rm -r %s/.repo' % self.manifest.topdir)
+      print('and try again.')
+
   def Execute(self, opt, args):
     git_require(MIN_GIT_VERSION, fail=True)
 
@@ -329,10 +354,4 @@
 
     self._ConfigureDepth(opt)
 
-    if self.manifest.IsMirror:
-      init_type = 'mirror '
-    else:
-      init_type = ''
-
-    print ''
-    print 'repo %sinitialized in %s' % (init_type, self.manifest.topdir)
+    self._DisplayResult()
diff --git a/subcmds/list.py b/subcmds/list.py
index 6058a75..0d5c27f 100644
--- a/subcmds/list.py
+++ b/subcmds/list.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import re
 
 from command import Command, MirrorSafeCommand
@@ -64,7 +65,7 @@
       lines.append("%s : %s" % (_getpath(project), project.name))
 
     lines.sort()
-    print '\n'.join(lines)
+    print('\n'.join(lines))
 
   def FindProjects(self, args):
     result = []
diff --git a/subcmds/manifest.py b/subcmds/manifest.py
index 5592a37..5ceeb12 100644
--- a/subcmds/manifest.py
+++ b/subcmds/manifest.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import sys
 
@@ -69,7 +70,7 @@
                        peg_rev_upstream = opt.peg_rev_upstream)
     fd.close()
     if opt.output_file != '-':
-      print >>sys.stderr, 'Saved manifest to %s' % opt.output_file
+      print('Saved manifest to %s' % opt.output_file, file=sys.stderr)
 
   def Execute(self, opt, args):
     if args:
@@ -79,6 +80,6 @@
       self._Output(opt)
       return
 
-    print >>sys.stderr, 'error: no operation to perform'
-    print >>sys.stderr, 'error: see repo help manifest'
+    print('error: no operation to perform', file=sys.stderr)
+    print('error: see repo help manifest', file=sys.stderr)
     sys.exit(1)
diff --git a/subcmds/overview.py b/subcmds/overview.py
index a509bd9..418459a 100644
--- a/subcmds/overview.py
+++ b/subcmds/overview.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 from color import Coloring
 from command import PagedCommand
 
@@ -54,8 +55,11 @@
       def __init__(self, config):
         Coloring.__init__(self, config, 'status')
         self.project = self.printer('header', attr='bold')
+        self.text = self.printer('text')
 
     out = Report(all_branches[0].project.config)
+    out.text("Deprecated. See repo info -o.")
+    out.nl()
     out.project('Projects Overview')
     out.nl()
 
@@ -70,11 +74,11 @@
 
       commits = branch.commits
       date = branch.date
-      print '%s %-33s (%2d commit%s, %s)' % (
+      print('%s %-33s (%2d commit%s, %s)' % (
             branch.name == project.CurrentBranch and '*' or ' ',
             branch.name,
             len(commits),
             len(commits) != 1 and 's' or ' ',
-            date)
+            date))
       for commit in commits:
-        print '%-35s   - %s' % ('', commit)
+        print('%-35s   - %s' % ('', commit))
diff --git a/subcmds/prune.py b/subcmds/prune.py
index c50a550..39c571a 100644
--- a/subcmds/prune.py
+++ b/subcmds/prune.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 from color import Coloring
 from command import PagedCommand
 
@@ -51,9 +52,9 @@
 
       commits = branch.commits
       date = branch.date
-      print '%s %-33s (%2d commit%s, %s)' % (
+      print('%s %-33s (%2d commit%s, %s)' % (
             branch.name == project.CurrentBranch and '*' or ' ',
             branch.name,
             len(commits),
             len(commits) != 1 and 's' or ' ',
-            date)
+            date))
diff --git a/subcmds/rebase.py b/subcmds/rebase.py
index a8d58cd..06cda22 100644
--- a/subcmds/rebase.py
+++ b/subcmds/rebase.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 
 from command import Command
@@ -59,14 +60,16 @@
     one_project = len(all_projects) == 1
 
     if opt.interactive and not one_project:
-      print >>sys.stderr, 'error: interactive rebase not supported with multiple projects'
+      print('error: interactive rebase not supported with multiple projects',
+            file=sys.stderr)
       return -1
 
     for project in all_projects:
       cb = project.CurrentBranch
       if not cb:
         if one_project:
-          print >>sys.stderr, "error: project %s has a detatched HEAD" % project.relpath
+          print("error: project %s has a detatched HEAD" % project.relpath,
+                file=sys.stderr)
           return -1
         # ignore branches with detatched HEADs
         continue
@@ -74,7 +77,8 @@
       upbranch = project.GetBranch(cb)
       if not upbranch.LocalMerge:
         if one_project:
-          print >>sys.stderr, "error: project %s does not track any remote branches" % project.relpath
+          print("error: project %s does not track any remote branches"
+                % project.relpath, file=sys.stderr)
           return -1
         # ignore branches without remotes
         continue
@@ -101,8 +105,8 @@
 
       args.append(upbranch.LocalMerge)
 
-      print >>sys.stderr, '# %s: rebasing %s -> %s' % \
-        (project.relpath, cb, upbranch.LocalMerge)
+      print('# %s: rebasing %s -> %s'
+            % (project.relpath, cb, upbranch.LocalMerge), file=sys.stderr)
 
       needs_stash = False
       if opt.auto_stash:
diff --git a/subcmds/selfupdate.py b/subcmds/selfupdate.py
index 46aa3a1..d12e08d 100644
--- a/subcmds/selfupdate.py
+++ b/subcmds/selfupdate.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 from optparse import SUPPRESS_HELP
 import sys
 
@@ -52,7 +53,7 @@
 
     else:
       if not rp.Sync_NetworkHalf():
-        print >>sys.stderr, "error: can't update repo"
+        print("error: can't update repo", file=sys.stderr)
         sys.exit(1)
 
       rp.bare_git.gc('--auto')
diff --git a/subcmds/stage.py b/subcmds/stage.py
index 2ec4806..ff15ee0 100644
--- a/subcmds/stage.py
+++ b/subcmds/stage.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 
 from color import Coloring
@@ -50,7 +51,7 @@
   def _Interactive(self, opt, args):
     all_projects = filter(lambda x: x.IsDirty(), self.GetProjects(args))
     if not all_projects:
-      print >>sys.stderr,'no projects have uncommitted modifications'
+      print('no projects have uncommitted modifications', file=sys.stderr)
       return
 
     out = _ProjectList(self.manifest.manifestProject.config)
@@ -58,7 +59,7 @@
       out.header('        %s', 'project')
       out.nl()
 
-      for i in xrange(0, len(all_projects)):
+      for i in range(len(all_projects)):
         p = all_projects[i]
         out.write('%3d:    %s', i + 1, p.relpath + '/')
         out.nl()
@@ -101,7 +102,7 @@
       if len(p) == 1:
         _AddI(p[0])
         continue
-    print 'Bye.'
+    print('Bye.')
 
 def _AddI(project):
   p = GitCommand(project, ['add', '--interactive'], bare=False)
diff --git a/subcmds/start.py b/subcmds/start.py
index be64531..2d723fc 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from command import Command
 from git_config import IsId
@@ -41,7 +42,7 @@
 
     nb = args[0]
     if not git.check_ref_format('heads/%s' % nb):
-      print >>sys.stderr, "error: '%s' is not a valid name" % nb
+      print("error: '%s' is not a valid name" % nb, file=sys.stderr)
       sys.exit(1)
 
     err = []
@@ -49,7 +50,7 @@
     if not opt.all:
       projects = args[1:]
       if len(projects) < 1:
-        print >>sys.stderr, "error: at least one project must be specified"
+        print("error: at least one project must be specified", file=sys.stderr)
         sys.exit(1)
 
     all_projects = self.GetProjects(projects)
@@ -67,7 +68,6 @@
 
     if err:
       for p in err:
-        print >>sys.stderr,\
-          "error: %s/: cannot start %s" \
-          % (p.relpath, nb)
+        print("error: %s/: cannot start %s" % (p.relpath, nb),
+              file=sys.stderr)
       sys.exit(1)
diff --git a/subcmds/status.py b/subcmds/status.py
index 7611621..cce00c8 100644
--- a/subcmds/status.py
+++ b/subcmds/status.py
@@ -20,10 +20,14 @@
 except ImportError:
   import dummy_threading as _threading
 
+import glob
 import itertools
+import os
 import sys
 import StringIO
 
+from color import Coloring
+
 class Status(PagedCommand):
   common = True
   helpSummary = "Show the working tree status"
@@ -39,6 +43,13 @@
 The -j/--jobs option can be used to run multiple status queries
 in parallel.
 
+The -o/--orphans option can be used to show objects that are in
+the working directory, but not associated with a repo project.
+This includes unmanaged top-level files and directories, but also
+includes deeper items.  For example, if dir/subdir/proj1 and
+dir/subdir/proj2 are repo projects, dir/subdir/proj3 will be shown
+if it is not known to repo.
+
 Status Display
 --------------
 
@@ -76,6 +87,9 @@
     p.add_option('-j', '--jobs',
                  dest='jobs', action='store', type='int', default=2,
                  help="number of projects to check simultaneously")
+    p.add_option('-o', '--orphans',
+                 dest='orphans', action='store_true',
+                 help="include objects in working directory outside of repo projects")
 
   def _StatusHelper(self, project, clean_counter, sem, output):
     """Obtains the status for a specific project.
@@ -97,6 +111,22 @@
     finally:
       sem.release()
 
+  def _FindOrphans(self, dirs, proj_dirs, proj_dirs_parents, outstring):
+    """find 'dirs' that are present in 'proj_dirs_parents' but not in 'proj_dirs'"""
+    status_header = ' --\t'
+    for item in dirs:
+      if not os.path.isdir(item):
+        outstring.write(''.join([status_header, item]))
+        continue
+      if item in proj_dirs:
+        continue
+      if item in proj_dirs_parents:
+        self._FindOrphans(glob.glob('%s/.*' % item) + \
+            glob.glob('%s/*' % item), \
+            proj_dirs, proj_dirs_parents, outstring)
+        continue
+      outstring.write(''.join([status_header, item, '/']))
+
   def Execute(self, opt, args):
     all_projects = self.GetProjects(args)
     counter = itertools.count()
@@ -129,4 +159,46 @@
         output.dump(sys.stdout)
         output.close()
     if len(all_projects) == counter.next():
-      print 'nothing to commit (working directory clean)'
+      print('nothing to commit (working directory clean)')
+
+    if opt.orphans:
+      proj_dirs = set()
+      proj_dirs_parents = set()
+      for project in self.GetProjects(None, missing_ok=True):
+        proj_dirs.add(project.relpath)
+        (head, _tail) = os.path.split(project.relpath)
+        while head != "":
+          proj_dirs_parents.add(head)
+          (head, _tail) = os.path.split(head)
+      proj_dirs.add('.repo')
+
+      class StatusColoring(Coloring):
+        def __init__(self, config):
+          Coloring.__init__(self, config, 'status')
+          self.project = self.printer('header', attr = 'bold')
+          self.untracked = self.printer('untracked', fg = 'red')
+
+      orig_path = os.getcwd()
+      try:
+        os.chdir(self.manifest.topdir)
+
+        outstring = StringIO.StringIO()
+        self._FindOrphans(glob.glob('.*') + \
+            glob.glob('*'), \
+            proj_dirs, proj_dirs_parents, outstring)
+
+        if outstring.buflist:
+          output = StatusColoring(self.manifest.globalConfig)
+          output.project('Objects not within a project (orphans)')
+          output.nl()
+          for entry in outstring.buflist:
+            output.untracked(entry)
+            output.nl()
+        else:
+          print('No orphan files or directories')
+
+        outstring.close()
+
+      finally:
+        # Restore CWD.
+        os.chdir(orig_path)
diff --git a/subcmds/sync.py b/subcmds/sync.py
index d4637d0..228a279 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import netrc
 from optparse import SUPPRESS_HELP
 import os
@@ -44,13 +45,13 @@
 except ImportError:
   multiprocessing = None
 
-from git_command import GIT
+from git_command import GIT, git_require
 from git_refs import R_HEADS, HEAD
 from main import WrapperModule
 from project import Project
 from project import RemoteSpec
 from command import Command, MirrorSafeCommand
-from error import RepoChangedException, GitError
+from error import RepoChangedException, GitError, ManifestParseError
 from project import SyncBuffer
 from progress import Progress
 
@@ -113,6 +114,9 @@
 may be necessary if there are problems with the local Python
 HTTP client or proxy configuration, but the Git binary works.
 
+The --fetch-submodules option enables fetching Git submodules
+of a project from server.
+
 SSH Connections
 ---------------
 
@@ -144,27 +148,30 @@
 """
 
   def _Options(self, p, show_smart=True):
-    self.jobs = self.manifest.default.sync_j
+    try:
+      self.jobs = self.manifest.default.sync_j
+    except ManifestParseError:
+      self.jobs = 1
 
     p.add_option('-f', '--force-broken',
                  dest='force_broken', action='store_true',
                  help="continue sync even if a project fails to sync")
-    p.add_option('-l','--local-only',
+    p.add_option('-l', '--local-only',
                  dest='local_only', action='store_true',
                  help="only update working tree, don't fetch")
-    p.add_option('-n','--network-only',
+    p.add_option('-n', '--network-only',
                  dest='network_only', action='store_true',
                  help="fetch only, don't update working tree")
-    p.add_option('-d','--detach',
+    p.add_option('-d', '--detach',
                  dest='detach_head', action='store_true',
                  help='detach projects back to manifest revision')
-    p.add_option('-c','--current-branch',
+    p.add_option('-c', '--current-branch',
                  dest='current_branch_only', action='store_true',
                  help='fetch only current branch from server')
-    p.add_option('-q','--quiet',
+    p.add_option('-q', '--quiet',
                  dest='quiet', action='store_true',
                  help='be more quiet')
-    p.add_option('-j','--jobs',
+    p.add_option('-j', '--jobs',
                  dest='jobs', action='store', type='int',
                  help="projects to fetch simultaneously (default %d)" % self.jobs)
     p.add_option('-m', '--manifest-name',
@@ -173,6 +180,15 @@
     p.add_option('--no-clone-bundle',
                  dest='no_clone_bundle', action='store_true',
                  help='disable use of /clone.bundle on HTTP/HTTPS')
+    p.add_option('-u', '--manifest-server-username', action='store',
+                 dest='manifest_server_username',
+                 help='username to authenticate with the manifest server')
+    p.add_option('-p', '--manifest-server-password', action='store',
+                 dest='manifest_server_password',
+                 help='password to authenticate with the manifest server')
+    p.add_option('--fetch-submodules',
+                 dest='fetch_submodules', action='store_true',
+                 help='fetch submodules from server')
     if show_smart:
       p.add_option('-s', '--smart-sync',
                    dest='smart_sync', action='store_true',
@@ -180,12 +196,6 @@
       p.add_option('-t', '--smart-tag',
                    dest='smart_tag', action='store',
                    help='smart sync using manifest from a known tag')
-      p.add_option('-u', '--manifest-server-username', action='store',
-                   dest='manifest_server_username',
-                   help='username to authenticate with the manifest server')
-      p.add_option('-p', '--manifest-server-password', action='store',
-                   dest='manifest_server_password',
-                   help='password to authenticate with the manifest server')
 
     g = p.add_option_group('repo Version options')
     g.add_option('--no-repo-verify',
@@ -196,61 +206,62 @@
                  help=SUPPRESS_HELP)
 
   def _FetchHelper(self, opt, project, lock, fetched, pm, sem, err_event):
-      """Main function of the fetch threads when jobs are > 1.
+    """Main function of the fetch threads when jobs are > 1.
 
-      Args:
-        opt: Program options returned from optparse.  See _Options().
-        project: Project object for the project to fetch.
-        lock: Lock for accessing objects that are shared amongst multiple
-            _FetchHelper() threads.
-        fetched: set object that we will add project.gitdir to when we're done
-            (with our lock held).
-        pm: Instance of a Project object.  We will call pm.update() (with our
-            lock held).
-        sem: We'll release() this semaphore when we exit so that another thread
-            can be started up.
-        err_event: We'll set this event in the case of an error (after printing
-            out info about the error).
-      """
-      # We'll set to true once we've locked the lock.
-      did_lock = False
+    Args:
+      opt: Program options returned from optparse.  See _Options().
+      project: Project object for the project to fetch.
+      lock: Lock for accessing objects that are shared amongst multiple
+          _FetchHelper() threads.
+      fetched: set object that we will add project.gitdir to when we're done
+          (with our lock held).
+      pm: Instance of a Project object.  We will call pm.update() (with our
+          lock held).
+      sem: We'll release() this semaphore when we exit so that another thread
+          can be started up.
+      err_event: We'll set this event in the case of an error (after printing
+          out info about the error).
+    """
+    # We'll set to true once we've locked the lock.
+    did_lock = False
 
-      # Encapsulate everything in a try/except/finally so that:
-      # - We always set err_event in the case of an exception.
-      # - We always make sure we call sem.release().
-      # - We always make sure we unlock the lock if we locked it.
+    # Encapsulate everything in a try/except/finally so that:
+    # - We always set err_event in the case of an exception.
+    # - We always make sure we call sem.release().
+    # - We always make sure we unlock the lock if we locked it.
+    try:
       try:
-        try:
-          start = time.time()
-          success = project.Sync_NetworkHalf(
-            quiet=opt.quiet,
-            current_branch_only=opt.current_branch_only,
-            clone_bundle=not opt.no_clone_bundle)
-          self._fetch_times.Set(project, time.time() - start)
+        start = time.time()
+        success = project.Sync_NetworkHalf(
+          quiet=opt.quiet,
+          current_branch_only=opt.current_branch_only,
+          clone_bundle=not opt.no_clone_bundle)
+        self._fetch_times.Set(project, time.time() - start)
 
-          # Lock around all the rest of the code, since printing, updating a set
-          # and Progress.update() are not thread safe.
-          lock.acquire()
-          did_lock = True
+        # Lock around all the rest of the code, since printing, updating a set
+        # and Progress.update() are not thread safe.
+        lock.acquire()
+        did_lock = True
 
-          if not success:
-            print >>sys.stderr, 'error: Cannot fetch %s' % project.name
-            if opt.force_broken:
-              print >>sys.stderr, 'warn: --force-broken, continuing to sync'
-            else:
-              raise _FetchError()
+        if not success:
+          print('error: Cannot fetch %s' % project.name, file=sys.stderr)
+          if opt.force_broken:
+            print('warn: --force-broken, continuing to sync',
+                  file=sys.stderr)
+          else:
+            raise _FetchError()
 
-          fetched.add(project.gitdir)
-          pm.update()
-        except _FetchError:
-          err_event.set()
-        except:
-          err_event.set()
-          raise
-      finally:
-        if did_lock:
-          lock.release()
-        sem.release()
+        fetched.add(project.gitdir)
+        pm.update()
+      except _FetchError:
+        err_event.set()
+      except:
+        err_event.set()
+        raise
+    finally:
+      if did_lock:
+        lock.release()
+      sem.release()
 
   def _Fetch(self, projects, opt):
     fetched = set()
@@ -265,9 +276,9 @@
             clone_bundle=not opt.no_clone_bundle):
           fetched.add(project.gitdir)
         else:
-          print >>sys.stderr, 'error: Cannot fetch %s' % project.name
+          print('error: Cannot fetch %s' % project.name, file=sys.stderr)
           if opt.force_broken:
-            print >>sys.stderr, 'warn: --force-broken, continuing to sync'
+            print('warn: --force-broken, continuing to sync', file=sys.stderr)
           else:
             sys.exit(1)
     else:
@@ -300,7 +311,7 @@
 
       # If we saw an error, exit with code 1 so that other scripts can check.
       if err_event.isSet():
-        print >>sys.stderr, '\nerror: Exited sync due to fetch errors'
+        print('\nerror: Exited sync due to fetch errors', file=sys.stderr)
         sys.exit(1)
 
     pm.end()
@@ -310,7 +321,8 @@
     return fetched
 
   def _GCProjects(self, projects):
-    if multiprocessing:
+    has_dash_c = git_require((1, 7, 2))
+    if multiprocessing and has_dash_c:
       cpu_count = multiprocessing.cpu_count()
     else:
       cpu_count = 1
@@ -352,7 +364,7 @@
       t.join()
 
     if err_event.isSet():
-      print >>sys.stderr, '\nerror: Exited sync due to gc errors'
+      print('\nerror: Exited sync due to gc errors', file=sys.stderr)
       sys.exit(1)
 
   def UpdateProjectList(self):
@@ -376,34 +388,36 @@
         if path not in new_project_paths:
           # If the path has already been deleted, we don't need to do it
           if os.path.exists(self.manifest.topdir + '/' + path):
-              project = Project(
-                             manifest = self.manifest,
-                             name = path,
-                             remote = RemoteSpec('origin'),
-                             gitdir = os.path.join(self.manifest.topdir,
-                                                   path, '.git'),
-                             worktree = os.path.join(self.manifest.topdir, path),
-                             relpath = path,
-                             revisionExpr = 'HEAD',
-                             revisionId = None,
-                             groups = None)
+            project = Project(
+                           manifest = self.manifest,
+                           name = path,
+                           remote = RemoteSpec('origin'),
+                           gitdir = os.path.join(self.manifest.topdir,
+                                                 path, '.git'),
+                           worktree = os.path.join(self.manifest.topdir, path),
+                           relpath = path,
+                           revisionExpr = 'HEAD',
+                           revisionId = None,
+                           groups = None)
 
-              if project.IsDirty():
-                print >>sys.stderr, 'error: Cannot remove project "%s": \
-uncommitted changes are present' % project.relpath
-                print >>sys.stderr, '       commit changes, then run sync again'
-                return -1
-              else:
-                print >>sys.stderr, 'Deleting obsolete path %s' % project.worktree
-                shutil.rmtree(project.worktree)
-                # Try deleting parent subdirs if they are empty
-                project_dir = os.path.dirname(project.worktree)
-                while project_dir != self.manifest.topdir:
-                  try:
-                    os.rmdir(project_dir)
-                  except OSError:
-                    break
-                  project_dir = os.path.dirname(project_dir)
+            if project.IsDirty():
+              print('error: Cannot remove project "%s": uncommitted changes'
+                    'are present' % project.relpath, file=sys.stderr)
+              print('       commit changes, then run sync again',
+                    file=sys.stderr)
+              return -1
+            else:
+              print('Deleting obsolete path %s' % project.worktree,
+                    file=sys.stderr)
+              shutil.rmtree(project.worktree)
+              # Try deleting parent subdirs if they are empty
+              project_dir = os.path.dirname(project.worktree)
+              while project_dir != self.manifest.topdir:
+                try:
+                  os.rmdir(project_dir)
+                except OSError:
+                  break
+                project_dir = os.path.dirname(project_dir)
 
     new_project_paths.sort()
     fd = open(file_path, 'w')
@@ -422,24 +436,24 @@
       self.jobs = min(self.jobs, (soft_limit - 5) / 3)
 
     if opt.network_only and opt.detach_head:
-      print >>sys.stderr, 'error: cannot combine -n and -d'
+      print('error: cannot combine -n and -d', file=sys.stderr)
       sys.exit(1)
     if opt.network_only and opt.local_only:
-      print >>sys.stderr, 'error: cannot combine -n and -l'
+      print('error: cannot combine -n and -l', file=sys.stderr)
       sys.exit(1)
     if opt.manifest_name and opt.smart_sync:
-      print >>sys.stderr, 'error: cannot combine -m and -s'
+      print('error: cannot combine -m and -s', file=sys.stderr)
       sys.exit(1)
     if opt.manifest_name and opt.smart_tag:
-      print >>sys.stderr, 'error: cannot combine -m and -t'
+      print('error: cannot combine -m and -t', file=sys.stderr)
       sys.exit(1)
     if opt.manifest_server_username or opt.manifest_server_password:
       if not (opt.smart_sync or opt.smart_tag):
-        print >>sys.stderr, 'error: -u and -p may only be combined with ' \
-                            '-s or -t'
+        print('error: -u and -p may only be combined with -s or -t',
+              file=sys.stderr)
         sys.exit(1)
       if None in [opt.manifest_server_username, opt.manifest_server_password]:
-        print >>sys.stderr, 'error: both -u and -p must be given'
+        print('error: both -u and -p must be given', file=sys.stderr)
         sys.exit(1)
 
     if opt.manifest_name:
@@ -447,8 +461,8 @@
 
     if opt.smart_sync or opt.smart_tag:
       if not self.manifest.manifest_server:
-        print >>sys.stderr, \
-            'error: cannot smart sync: no manifest server defined in manifest'
+        print('error: cannot smart sync: no manifest server defined in'
+              'manifest', file=sys.stderr)
         sys.exit(1)
 
       manifest_server = self.manifest.manifest_server
@@ -463,7 +477,8 @@
           try:
             info = netrc.netrc()
           except IOError:
-            print >>sys.stderr, '.netrc file does not exist or could not be opened'
+            print('.netrc file does not exist or could not be opened',
+                  file=sys.stderr)
           else:
             try:
               parse_result = urlparse.urlparse(manifest_server)
@@ -473,10 +488,10 @@
             except TypeError:
               # TypeError is raised when the given hostname is not present
               # in the .netrc file.
-              print >>sys.stderr, 'No credentials found for %s in .netrc' % \
-                                  parse_result.hostname
+              print('No credentials found for %s in .netrc'
+                    % parse_result.hostname, file=sys.stderr)
             except netrc.NetrcParseError as e:
-              print >>sys.stderr, 'Error parsing .netrc file: %s' % e
+              print('Error parsing .netrc file: %s' % e, file=sys.stderr)
 
         if (username and password):
           manifest_server = manifest_server.replace('://', '://%s:%s@' %
@@ -515,20 +530,21 @@
             finally:
               f.close()
           except IOError:
-            print >>sys.stderr, 'error: cannot write manifest to %s' % \
-                manifest_path
+            print('error: cannot write manifest to %s' % manifest_path,
+                  file=sys.stderr)
             sys.exit(1)
           self.manifest.Override(manifest_name)
         else:
-          print >>sys.stderr, 'error: %s' % manifest_str
+          print('error: %s' % manifest_str, file=sys.stderr)
           sys.exit(1)
       except (socket.error, IOError, xmlrpclib.Fault) as e:
-        print >>sys.stderr, 'error: cannot connect to manifest server %s:\n%s' % (
-            self.manifest.manifest_server, e)
+        print('error: cannot connect to manifest server %s:\n%s'
+              % (self.manifest.manifest_server, e), file=sys.stderr)
         sys.exit(1)
       except xmlrpclib.ProtocolError as e:
-        print >>sys.stderr, 'error: cannot connect to manifest server %s:\n%d %s' % (
-            self.manifest.manifest_server, e.errcode, e.errmsg)
+        print('error: cannot connect to manifest server %s:\n%d %s'
+              % (self.manifest.manifest_server, e.errcode, e.errmsg),
+              file=sys.stderr)
         sys.exit(1)
 
     rp = self.manifest.repoProject
@@ -552,7 +568,9 @@
       self.manifest._Unload()
       if opt.jobs is None:
         self.jobs = self.manifest.default.sync_j
-    all_projects = self.GetProjects(args, missing_ok=True)
+    all_projects = self.GetProjects(args,
+                                    missing_ok=True,
+                                    submodules_ok=opt.fetch_submodules)
 
     self._fetch_times = _FetchTimes(self.manifest)
     if not opt.local_only:
@@ -563,12 +581,33 @@
       to_fetch.extend(all_projects)
       to_fetch.sort(key=self._fetch_times.Get, reverse=True)
 
-      self._Fetch(to_fetch, opt)
+      fetched = self._Fetch(to_fetch, opt)
       _PostRepoFetch(rp, opt.no_repo_verify)
       if opt.network_only:
         # bail out now; the rest touches the working tree
         return
 
+      # Iteratively fetch missing and/or nested unregistered submodules
+      previously_missing_set = set()
+      while True:
+        self.manifest._Unload()
+        all_projects = self.GetProjects(args,
+                                        missing_ok=True,
+                                        submodules_ok=opt.fetch_submodules)
+        missing = []
+        for project in all_projects:
+          if project.gitdir not in fetched:
+            missing.append(project)
+        if not missing:
+          break
+        # Stop us from non-stopped fetching actually-missing repos: If set of
+        # missing repos has not been changed from last fetch, we break.
+        missing_set = set(p.name for p in missing)
+        if previously_missing_set == missing_set:
+          break
+        previously_missing_set = missing_set
+        fetched.update(self._Fetch(missing, opt))
+
     if self.manifest.IsMirror:
       # bail out now, we have no working tree
       return
@@ -584,14 +623,14 @@
       if project.worktree:
         project.Sync_LocalHalf(syncbuf)
     pm.end()
-    print >>sys.stderr
+    print(file=sys.stderr)
     if not syncbuf.Finish():
       sys.exit(1)
 
     # If there's a notice that's supposed to print at the end of the sync, print
     # it now...
     if self.manifest.notice:
-      print self.manifest.notice
+      print(self.manifest.notice)
 
 def _PostRepoUpgrade(manifest, quiet=False):
   wrapper = WrapperModule()
@@ -603,27 +642,28 @@
 
 def _PostRepoFetch(rp, no_repo_verify=False, verbose=False):
   if rp.HasChanges:
-    print >>sys.stderr, 'info: A new version of repo is available'
-    print >>sys.stderr, ''
+    print('info: A new version of repo is available', file=sys.stderr)
+    print(file=sys.stderr)
     if no_repo_verify or _VerifyTag(rp):
       syncbuf = SyncBuffer(rp.config)
       rp.Sync_LocalHalf(syncbuf)
       if not syncbuf.Finish():
         sys.exit(1)
-      print >>sys.stderr, 'info: Restarting repo with latest version'
+      print('info: Restarting repo with latest version', file=sys.stderr)
       raise RepoChangedException(['--repo-upgraded'])
     else:
-      print >>sys.stderr, 'warning: Skipped upgrade to unverified version'
+      print('warning: Skipped upgrade to unverified version', file=sys.stderr)
   else:
     if verbose:
-      print >>sys.stderr, 'repo version %s is current' % rp.work_git.describe(HEAD)
+      print('repo version %s is current' % rp.work_git.describe(HEAD),
+            file=sys.stderr)
 
 def _VerifyTag(project):
   gpg_dir = os.path.expanduser('~/.repoconfig/gnupg')
   if not os.path.exists(gpg_dir):
-    print >>sys.stderr,\
-"""warning: GnuPG was not available during last "repo init"
-warning: Cannot automatically authenticate repo."""
+    print('warning: GnuPG was not available during last "repo init"\n'
+          'warning: Cannot automatically authenticate repo."""',
+          file=sys.stderr)
     return True
 
   try:
@@ -637,10 +677,9 @@
     if rev.startswith(R_HEADS):
       rev = rev[len(R_HEADS):]
 
-    print >>sys.stderr
-    print >>sys.stderr,\
-      "warning: project '%s' branch '%s' is not signed" \
-      % (project.name, rev)
+    print(file=sys.stderr)
+    print("warning: project '%s' branch '%s' is not signed"
+          % (project.name, rev), file=sys.stderr)
     return False
 
   env = os.environ.copy()
@@ -659,10 +698,10 @@
   proc.stderr.close()
 
   if proc.wait() != 0:
-    print >>sys.stderr
-    print >>sys.stderr, out
-    print >>sys.stderr, err
-    print >>sys.stderr
+    print(file=sys.stderr)
+    print(out, file=sys.stderr)
+    print(err, file=sys.stderr)
+    print(file=sys.stderr)
     return False
   return True
 
@@ -696,7 +735,7 @@
       try:
         try:
           self._times = pickle.load(f)
-        except:
+        except IOError:
           try:
             os.remove(self._path)
           except OSError:
diff --git a/subcmds/upload.py b/subcmds/upload.py
index 84a5e44..e314032 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import copy
 import re
 import sys
@@ -26,16 +27,18 @@
 
 def _ConfirmManyUploads(multiple_branches=False):
   if multiple_branches:
-    print "ATTENTION: One or more branches has an unusually high number of commits."
+    print('ATTENTION: One or more branches has an unusually high number'
+          'of commits.')
   else:
-    print "ATTENTION: You are uploading an unusually high number of commits."
-  print "YOU PROBABLY DO NOT MEAN TO DO THIS. (Did you rebase across branches?)"
+    print('ATTENTION: You are uploading an unusually high number of commits.')
+  print('YOU PROBABLY DO NOT MEAN TO DO THIS. (Did you rebase across'
+        'branches?)')
   answer = raw_input("If you are sure you intend to do this, type 'yes': ").strip()
   return answer == "yes"
 
 def _die(fmt, *args):
   msg = fmt % args
-  print >>sys.stderr, 'error: %s' % msg
+  print('error: %s' % msg, file=sys.stderr)
   sys.exit(1)
 
 def _SplitEmails(values):
@@ -47,7 +50,7 @@
 class Upload(InteractiveCommand):
   common = True
   helpSummary = "Upload changes for code review"
-  helpUsage="""
+  helpUsage = """
 %prog [--re --cc] [<project>]...
 """
   helpDescription = """
@@ -176,18 +179,18 @@
       date = branch.date
       commit_list = branch.commits
 
-      print 'Upload project %s/ to remote branch %s:' % (project.relpath, project.revisionExpr)
-      print '  branch %s (%2d commit%s, %s):' % (
+      print('Upload project %s/ to remote branch %s:' % (project.relpath, project.revisionExpr))
+      print('  branch %s (%2d commit%s, %s):' % (
                     name,
                     len(commit_list),
                     len(commit_list) != 1 and 's' or '',
-                    date)
+                    date))
       for commit in commit_list:
-        print '         %s' % commit
+        print('         %s' % commit)
 
       sys.stdout.write('to %s (y/N)? ' % remote.review)
-      answer = sys.stdin.readline().strip()
-      answer = answer in ('y', 'Y', 'yes', '1', 'true', 't')
+      answer = sys.stdin.readline().strip().lower()
+      answer = answer in ('y', 'yes', '1', 'true', 't')
 
     if answer:
       if len(branch.commits) > UNUSUAL_COMMIT_THRESHOLD:
@@ -297,7 +300,7 @@
     try:
       # refs/changes/XYZ/N --> XYZ
       return refs.get(last_pub).split('/')[-2]
-    except:
+    except (AttributeError, IndexError):
       return ""
 
   def _UploadAndReport(self, opt, todo, original_people):
@@ -309,23 +312,23 @@
 
         # Check if there are local changes that may have been forgotten
         if branch.project.HasChanges():
-            key = 'review.%s.autoupload' % branch.project.remote.review
-            answer = branch.project.config.GetBoolean(key)
+          key = 'review.%s.autoupload' % branch.project.remote.review
+          answer = branch.project.config.GetBoolean(key)
 
-            # if they want to auto upload, let's not ask because it could be automated
-            if answer is None:
-                sys.stdout.write('Uncommitted changes in ' + branch.project.name + ' (did you forget to amend?). Continue uploading? (y/N) ')
-                a = sys.stdin.readline().strip().lower()
-                if a not in ('y', 'yes', 't', 'true', 'on'):
-                    print >>sys.stderr, "skipping upload"
-                    branch.uploaded = False
-                    branch.error = 'User aborted'
-                    continue
+          # if they want to auto upload, let's not ask because it could be automated
+          if answer is None:
+            sys.stdout.write('Uncommitted changes in ' + branch.project.name + ' (did you forget to amend?). Continue uploading? (y/N) ')
+            a = sys.stdin.readline().strip().lower()
+            if a not in ('y', 'yes', 't', 'true', 'on'):
+              print("skipping upload", file=sys.stderr)
+              branch.uploaded = False
+              branch.error = 'User aborted'
+              continue
 
         # Check if topic branches should be sent to the server during upload
         if opt.auto_topic is not True:
-           key = 'review.%s.uploadtopic' % branch.project.remote.review
-           opt.auto_topic = branch.project.config.GetBoolean(key)
+          key = 'review.%s.uploadtopic' % branch.project.remote.review
+          opt.auto_topic = branch.project.config.GetBoolean(key)
 
         branch.UploadForReview(people, auto_topic=opt.auto_topic, draft=opt.draft)
         branch.uploaded = True
@@ -334,8 +337,8 @@
         branch.uploaded = False
         have_errors = True
 
-    print >>sys.stderr, ''
-    print >>sys.stderr, '----------------------------------------------------------------------'
+    print(file=sys.stderr)
+    print('----------------------------------------------------------------------', file=sys.stderr)
 
     if have_errors:
       for branch in todo:
@@ -344,17 +347,19 @@
             fmt = ' (%s)'
           else:
             fmt = '\n       (%s)'
-          print >>sys.stderr, ('[FAILED] %-15s %-15s' + fmt) % (
+          print(('[FAILED] %-15s %-15s' + fmt) % (
                  branch.project.relpath + '/', \
                  branch.name, \
-                 str(branch.error))
-      print >>sys.stderr, ''
+                 str(branch.error)),
+                 file=sys.stderr)
+      print()
 
     for branch in todo:
-        if branch.uploaded:
-          print >>sys.stderr, '[OK    ] %-15s %s' % (
-                 branch.project.relpath + '/',
-                 branch.name)
+      if branch.uploaded:
+        print('[OK    ] %-15s %s' % (
+               branch.project.relpath + '/',
+               branch.name),
+               file=sys.stderr)
 
     if have_errors:
       sys.exit(1)
@@ -385,17 +390,17 @@
       try:
         hook.Run(opt.allow_all_hooks, project_list=pending_proj_names)
       except HookError as e:
-        print >>sys.stderr, "ERROR: %s" % str(e)
+        print("ERROR: %s" % str(e), file=sys.stderr)
         return
 
     if opt.reviewers:
       reviewers = _SplitEmails(opt.reviewers)
     if opt.cc:
       cc = _SplitEmails(opt.cc)
-    people = (reviewers,cc)
+    people = (reviewers, cc)
 
     if not pending:
-      print >>sys.stdout, "no branches ready for upload"
+      print("no branches ready for upload", file=sys.stderr)
     elif len(pending) == 1 and len(pending[0][1]) == 1:
       self._SingleBranch(opt, pending[0][1][0], people)
     else:
diff --git a/subcmds/version.py b/subcmds/version.py
index 243e367..01b7fd8 100644
--- a/subcmds/version.py
+++ b/subcmds/version.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 from command import Command, MirrorSafeCommand
 from git_command import git
@@ -32,12 +33,12 @@
     rp = self.manifest.repoProject
     rem = rp.GetRemote(rp.remote.name)
 
-    print 'repo version %s' % rp.work_git.describe(HEAD)
-    print '       (from %s)' % rem.url
+    print('repo version %s' % rp.work_git.describe(HEAD))
+    print('       (from %s)' % rem.url)
 
     if Version.wrapper_path is not None:
-      print 'repo launcher version %s' % Version.wrapper_version
-      print '       (from %s)' % Version.wrapper_path
+      print('repo launcher version %s' % Version.wrapper_version)
+      print('       (from %s)' % Version.wrapper_path)
 
-    print git.version().strip()
-    print 'Python %s' % sys.version
+    print(git.version().strip())
+    print('Python %s' % sys.version)
diff --git a/tests/test_git_config.py b/tests/test_git_config.py
index 5b1770e..3d4b997 100644
--- a/tests/test_git_config.py
+++ b/tests/test_git_config.py
@@ -4,49 +4,49 @@
 import git_config
 
 def fixture(*paths):
-    """Return a path relative to test/fixtures.
-    """
-    return os.path.join(os.path.dirname(__file__), 'fixtures', *paths)
+  """Return a path relative to test/fixtures.
+  """
+  return os.path.join(os.path.dirname(__file__), 'fixtures', *paths)
 
 class GitConfigUnitTest(unittest.TestCase):
-    """Tests the GitConfig class.
+  """Tests the GitConfig class.
+  """
+  def setUp(self):
+    """Create a GitConfig object using the test.gitconfig fixture.
     """
-    def setUp(self):
-        """Create a GitConfig object using the test.gitconfig fixture.
-        """
-        config_fixture = fixture('test.gitconfig')
-        self.config = git_config.GitConfig(config_fixture)
+    config_fixture = fixture('test.gitconfig')
+    self.config = git_config.GitConfig(config_fixture)
 
-    def test_GetString_with_empty_config_values(self):
-        """
-        Test config entries with no value.
+  def test_GetString_with_empty_config_values(self):
+    """
+    Test config entries with no value.
 
-        [section]
-            empty
+    [section]
+        empty
 
-        """
-        val = self.config.GetString('section.empty')
-        self.assertEqual(val, None)
+    """
+    val = self.config.GetString('section.empty')
+    self.assertEqual(val, None)
 
-    def test_GetString_with_true_value(self):
-        """
-        Test config entries with a string value.
+  def test_GetString_with_true_value(self):
+    """
+    Test config entries with a string value.
 
-        [section]
-            nonempty = true
+    [section]
+        nonempty = true
 
-        """
-        val = self.config.GetString('section.nonempty')
-        self.assertEqual(val, 'true')
+    """
+    val = self.config.GetString('section.nonempty')
+    self.assertEqual(val, 'true')
 
-    def test_GetString_from_missing_file(self):
-        """
-        Test missing config file
-        """
-        config_fixture = fixture('not.present.gitconfig')
-        config = git_config.GitConfig(config_fixture)
-        val = config.GetString('empty')
-        self.assertEqual(val, None)
+  def test_GetString_from_missing_file(self):
+    """
+    Test missing config file
+    """
+    config_fixture = fixture('not.present.gitconfig')
+    config = git_config.GitConfig(config_fixture)
+    val = config.GetString('empty')
+    self.assertEqual(val, None)
 
 if __name__ == '__main__':
-    unittest.main()
+  unittest.main()
diff --git a/trace.py b/trace.py
index 0376d2b..db42a68 100644
--- a/trace.py
+++ b/trace.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import sys
 import os
 REPO_TRACE = 'REPO_TRACE'
@@ -31,4 +32,4 @@
 
 def Trace(fmt, *args):
   if IsTrace():
-    print >>sys.stderr, fmt % args
+    print(fmt % args, file=sys.stderr)