diff --git a/gclient_scm.py b/gclient_scm.py
index 0389f4662..5ba1cd619 100644
--- a/gclient_scm.py
+++ b/gclient_scm.py
@@ -302,55 +302,66 @@ class GitWrapper(SCMWrapper):
       # hash is also a tag, only make a distinction at checkout
       rev_type = "hash"
 
-    if (not os.path.exists(self.checkout_path) or
-        (os.path.isdir(self.checkout_path) and
-         not os.path.exists(os.path.join(self.checkout_path, '.git')))):
-      self._Clone(revision, url, options)
-      self.UpdateSubmoduleConfig()
-      if file_list is not None:
-        files = self._Capture(['ls-files']).splitlines()
-        file_list.extend([os.path.join(self.checkout_path, f) for f in files])
-      if not verbose:
-        # Make the output a little prettier. It's nice to have some whitespace
-        # between projects when cloning.
-        print('')
-      return self._Capture(['rev-parse', '--verify', 'HEAD'])
-
     if not managed:
       self._UpdateBranchHeads(options, fetch=False)
       self.UpdateSubmoduleConfig()
       print ('________ unmanaged solution; skipping %s' % self.relpath)
       return self._Capture(['rev-parse', '--verify', 'HEAD'])
 
-    if not os.path.exists(os.path.join(self.checkout_path, '.git')):
-      raise gclient_utils.Error('\n____ %s%s\n'
-                                '\tPath is not a git repo. No .git dir.\n'
-                                '\tTo resolve:\n'
-                                '\t\trm -rf %s\n'
-                                '\tAnd run gclient sync again\n'
-                                % (self.relpath, rev_str, self.relpath))
+    needs_delete = False
+    exists = os.path.exists(self.checkout_path)
+    if exists and not os.path.exists(os.path.join(self.checkout_path, '.git')):
+      needs_delete = True
 
     # See if the url has changed (the unittests use git://foo for the url, let
     # that through).
-    current_url = self._Capture(['config', 'remote.%s.url' % self.remote])
     return_early = False
-    # TODO(maruel): Delete url != 'git://foo' since it's just to make the
-    # unit test pass. (and update the comment above)
-    # Skip url auto-correction if remote.origin.gclient-auto-fix-url is set.
-    # This allows devs to use experimental repos which have a different url
-    # but whose branch(s) are the same as official repos.
-    if (current_url != url and
-        url != 'git://foo' and
-        subprocess2.capture(
-            ['git', 'config', 'remote.%s.gclient-auto-fix-url' % self.remote],
-            cwd=self.checkout_path).strip() != 'False'):
-      print('_____ switching %s to a new upstream' % self.relpath)
-      # Make sure it's clean
-      self._CheckClean(rev_str)
-      # Switch over to the new upstream
-      self._Run(['remote', 'set-url', self.remote, url], options)
-      self._FetchAndReset(revision, file_list, options)
-      return_early = True
+    if exists and not needs_delete:
+      current_url = self._Capture(['config', 'remote.%s.url' % self.remote])
+      # TODO(maruel): Delete url != 'git://foo' since it's just to make the
+      # unit test pass. (and update the comment above)
+      # Skip url auto-correction if remote.origin.gclient-auto-fix-url is set.
+      # This allows devs to use experimental repos which have a different url
+      # but whose branch(s) are the same as official repos.
+      if (current_url != url and url != 'git://foo'):
+        auto_fix = 'True'
+        try:
+          auto_fix = self._Capture(
+              ['config', 'remote.%s.gclient-auto-fix-url' % self.remote],
+              cwd=self.checkout_path).strip()
+        except subprocess2.CalledProcessError:
+          pass
+        if auto_fix in ('1', 'true', 'True', 'yes', 'Yes', 'y', 'Y'):
+          print('_____ switching %s to a new upstream' % self.relpath)
+          # Make sure it's clean
+          self._CheckClean(rev_str)
+          # Switch over to the new upstream
+          self._Run(['remote', 'set-url', self.remote, url], options)
+          self._FetchAndReset(revision, file_list, options)
+          return_early = True
+
+    if (needs_delete and
+        gclient_utils.enable_deletion_of_conflicting_checkouts()):
+      if options.force:
+        print('Conflicting directory found in %s. Removing.'
+              % self.checkout_path)
+        gclient_utils.rmtree(self.checkout_path)
+      else:
+        raise gclient_utils.Error('Conflicting directory found in %s. Please '
+                                  'delete it or run with --force.'
+                                  % self.checkout_path)
+
+    if not os.path.exists(self.checkout_path):
+      self._Clone(revision, url, options)
+      self.UpdateSubmoduleConfig()
+      if file_list is not None:
+        files = self._Capture(['ls-files']).splitlines()
+        file_list.extend([os.path.join(self.checkout_path, f) for f in files])
+      if not verbose:
+        # Make the output a little prettier. It's nice to have some whitespace
+        # between projects when cloning.
+        print('')
+      return self._Capture(['rev-parse', '--verify', 'HEAD'])
 
     # Need to do this in the normal path as well as in the post-remote-switch
     # path.
@@ -625,7 +636,7 @@ class GitWrapper(SCMWrapper):
     elif rev.isdigit() and len(rev) < 7:
       # Handles an SVN rev.  As an optimization, only verify an SVN revision as
       # [0-9]{1,6} for now to avoid making a network request.
-      if scm.GIT.IsGitSvn(cwd=self.checkout_path):
+      if scm.GIT.IsGitSvn(self.checkout_path):
         local_head = scm.GIT.GetGitSvnHeadRev(cwd=self.checkout_path)
         if not local_head or local_head < int(rev):
           try:
@@ -1104,17 +1115,6 @@ class SVNWrapper(SCMWrapper):
     Raises:
       Error: if can't get URL for relative path.
     """
-    # Only update if git or hg is not controlling the directory.
-    git_path = os.path.join(self.checkout_path, '.git')
-    if os.path.exists(git_path):
-      print('________ found .git directory; skipping %s' % self.relpath)
-      return
-
-    hg_path = os.path.join(self.checkout_path, '.hg')
-    if os.path.exists(hg_path):
-      print('________ found .hg directory; skipping %s' % self.relpath)
-      return
-
     if args:
       raise gclient_utils.Error("Unsupported argument(s): %s" % ",".join(args))
 
@@ -1140,21 +1140,86 @@ class SVNWrapper(SCMWrapper):
       forced_revision = False
       rev_str = ''
 
+    if not managed:
+      print ('________ unmanaged solution; skipping %s' % self.relpath)
+      return self.Svnversion()
+
     # Get the existing scm url and the revision number of the current checkout.
     exists = os.path.exists(self.checkout_path)
-    if exists and managed:
+    needs_delete = False
+    from_info = None
+
+    if exists:
+      # If there's a git-svn checkout, verify that the svn-remote is correct.
+      if scm.GIT.IsGitSvn(self.checkout_path):
+        remote_url = scm.GIT.Capture(['config', '--local', '--get',
+                                      'svn-remote.svn.url'],
+                                     cwd=self.checkout_path).rstrip()
+        if remote_url != base_url:
+          needs_delete = True
+        else:
+          print('\n_____ %s looks like a git-svn checkout. Skipping.'
+                % self.relpath)
+          return # TODO(borenet): Get the svn revision number?
+
       try:
         from_info = scm.SVN.CaptureLocalInfo(
             [], os.path.join(self.checkout_path, '.'))
       except (gclient_utils.Error, subprocess2.CalledProcessError):
-        if options.reset and options.delete_unversioned_trees:
-          print 'Removing troublesome path %s' % self.checkout_path
-          gclient_utils.rmtree(self.checkout_path)
-          exists = False
-        else:
-          msg = ('Can\'t update/checkout %s if an unversioned directory is '
-                 'present. Delete the directory and try again.')
-          raise gclient_utils.Error(msg % self.checkout_path)
+        if gclient_utils.enable_deletion_of_conflicting_checkouts():
+          needs_delete = True
+        else: # TODO(borenet): Remove this once we can get rid of the guard.
+          if options.reset and options.delete_unversioned_trees:
+            print 'Removing troublesome path %s' % self.checkout_path
+            gclient_utils.rmtree(self.checkout_path)
+            exists = False
+          else:
+            msg = ('Can\'t update/checkout %s if an unversioned directory is '
+                   'present. Delete the directory and try again.')
+            raise gclient_utils.Error(msg % self.checkout_path)
+
+    # Switch the checkout if necessary.
+    if not needs_delete and from_info and from_info['URL'] != base_url:
+      # The repository url changed, need to switch.
+      try:
+        to_info = scm.SVN.CaptureRemoteInfo(url)
+      except (gclient_utils.Error, subprocess2.CalledProcessError):
+        # The url is invalid or the server is not accessible, it's safer to bail
+        # out right now.
+        raise gclient_utils.Error('This url is unreachable: %s' % url)
+      can_switch = ((from_info['Repository Root'] != to_info['Repository Root'])
+                    and (from_info['UUID'] == to_info['UUID']))
+      if can_switch:
+        print('\n_____ relocating %s to a new checkout' % self.relpath)
+        # We have different roots, so check if we can switch --relocate.
+        # Subversion only permits this if the repository UUIDs match.
+        # Perform the switch --relocate, then rewrite the from_url
+        # to reflect where we "are now."  (This is the same way that
+        # Subversion itself handles the metadata when switch --relocate
+        # is used.)  This makes the checks below for whether we
+        # can update to a revision or have to switch to a different
+        # branch work as expected.
+        # TODO(maruel):  TEST ME !
+        command = ['switch', '--relocate',
+                   from_info['Repository Root'],
+                   to_info['Repository Root'],
+                   self.relpath]
+        self._Run(command, options, cwd=self._root_dir)
+        from_info['URL'] = from_info['URL'].replace(
+            from_info['Repository Root'],
+            to_info['Repository Root'])
+      else:
+        needs_delete = True
+
+    if (needs_delete and
+        gclient_utils.enable_deletion_of_conflicting_checkouts()):
+      if options.force:
+        gclient_utils.rmtree(self.checkout_path)
+        exists = False
+      else:
+        raise gclient_utils.Error('Conflicting directory found in %s. Please '
+                                  'delete it or run with --force.'
+                                  % self.checkout_path)
 
     BASE_URLS = {
         '/chrome/trunk/src': 'gs://chromium-svn-checkout/chrome/',
@@ -1232,10 +1297,6 @@ class SVNWrapper(SCMWrapper):
       self._RunAndGetFileList(command, options, file_list, self._root_dir)
       return self.Svnversion()
 
-    if not managed:
-      print ('________ unmanaged solution; skipping %s' % self.relpath)
-      return self.Svnversion()
-
     if 'URL' not in from_info:
       raise gclient_utils.Error(
           ('gclient is confused. Couldn\'t get the url for %s.\n'
@@ -1277,53 +1338,6 @@ class SVNWrapper(SCMWrapper):
       revision = str(from_info_live['Revision'])
       rev_str = ' at %s' % revision
 
-    if from_info['URL'] != base_url:
-      # The repository url changed, need to switch.
-      try:
-        to_info = scm.SVN.CaptureRemoteInfo(url)
-      except (gclient_utils.Error, subprocess2.CalledProcessError):
-        # The url is invalid or the server is not accessible, it's safer to bail
-        # out right now.
-        raise gclient_utils.Error('This url is unreachable: %s' % url)
-      can_switch = ((from_info['Repository Root'] != to_info['Repository Root'])
-                    and (from_info['UUID'] == to_info['UUID']))
-      if can_switch:
-        print('\n_____ relocating %s to a new checkout' % self.relpath)
-        # We have different roots, so check if we can switch --relocate.
-        # Subversion only permits this if the repository UUIDs match.
-        # Perform the switch --relocate, then rewrite the from_url
-        # to reflect where we "are now."  (This is the same way that
-        # Subversion itself handles the metadata when switch --relocate
-        # is used.)  This makes the checks below for whether we
-        # can update to a revision or have to switch to a different
-        # branch work as expected.
-        # TODO(maruel):  TEST ME !
-        command = ['switch', '--relocate',
-                   from_info['Repository Root'],
-                   to_info['Repository Root'],
-                   self.relpath]
-        self._Run(command, options, cwd=self._root_dir)
-        from_info['URL'] = from_info['URL'].replace(
-            from_info['Repository Root'],
-            to_info['Repository Root'])
-      else:
-        if not options.force and not options.reset:
-          # Look for local modifications but ignore unversioned files.
-          for status in scm.SVN.CaptureStatus(None, self.checkout_path):
-            if status[0][0] != '?':
-              raise gclient_utils.Error(
-                  ('Can\'t switch the checkout to %s; UUID don\'t match and '
-                   'there is local changes in %s. Delete the directory and '
-                   'try again.') % (url, self.checkout_path))
-        # Ok delete it.
-        print('\n_____ switching %s to a new checkout' % self.relpath)
-        gclient_utils.rmtree(self.checkout_path)
-        # We need to checkout.
-        command = ['checkout', url, self.checkout_path]
-        command = self._AddAdditionalUpdateFlags(command, options, revision)
-        self._RunAndGetFileList(command, options, file_list, self._root_dir)
-        return self.Svnversion()
-
     # If the provided url has a revision number that matches the revision
     # number of the existing directory, then we don't need to bother updating.
     if not options.force and str(from_info['Revision']) == revision:
@@ -1393,9 +1407,6 @@ class SVNWrapper(SCMWrapper):
       if os.path.isdir(os.path.join(self.checkout_path, '.git')):
         print('________ found .git directory; skipping %s' % self.relpath)
         return
-      if os.path.isdir(os.path.join(self.checkout_path, '.hg')):
-        print('________ found .hg directory; skipping %s' % self.relpath)
-        return
       if not options.force:
         raise gclient_utils.Error('Invalid checkout path, aborting')
       print(
diff --git a/gclient_utils.py b/gclient_utils.py
index 47ea50286..11bd9fc84 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -10,6 +10,7 @@ import os
 import pipes
 import Queue
 import re
+import socket
 import stat
 import subprocess
 import sys
@@ -25,6 +26,20 @@ RETRY_MAX = 3
 RETRY_INITIAL_SLEEP = 0.5
 
 
+def enable_deletion_of_conflicting_checkouts():
+  """Determines whether to enable new checkout deletion behavior.
+
+  Initially, enables the experimental functionality on a small set of
+  bots.
+  """
+  # TODO(borenet): Remove this hack as soon as we've verified that it
+  # doesn't cause the bots to break.
+  if not os.environ.get('CHROME_HEADLESS'):
+    return False
+  return socket.gethostname() in ('vm859-m1', 'BUILD1-M1',
+                                  'vm630-m1.golo.chromium.org')
+
+
 class Error(Exception):
   """gclient exception class."""
   def __init__(self, msg, *args, **kwargs):
diff --git a/scm.py b/scm.py
index 30bb3d17e..1d1b98f31 100644
--- a/scm.py
+++ b/scm.py
@@ -166,12 +166,15 @@ class GIT(object):
     return GIT.ShortBranchName(GIT.GetBranchRef(cwd))
 
   @staticmethod
-  def IsGitSvn(cwd):
+  def IsGitSvn(checkout_root):
     """Returns true if this repo looks like it's using git-svn."""
+    # A git-svn checkout has a .git directory.
+    if not os.path.exists(os.path.join(checkout_root, '.git')):
+      return False
     # If you have any "svn-remote.*" config keys, we think you're using svn.
     try:
       GIT.Capture(['config', '--local', '--get-regexp', r'^svn-remote\.'],
-                  cwd=cwd)
+                  cwd=checkout_root)
       return True
     except subprocess2.CalledProcessError:
       return False
@@ -408,7 +411,7 @@ class GIT(object):
   @staticmethod
   def GetSha1ForSvnRev(cwd, rev):
     """Returns a corresponding git sha1 for a SVN revision."""
-    if not GIT.IsGitSvn(cwd=cwd):
+    if not GIT.IsGitSvn(cwd):
       return None
     try:
       output = GIT.Capture(['svn', 'find-rev', 'r' + str(rev)], cwd=cwd)
diff --git a/tests/gclient_scm_test.py b/tests/gclient_scm_test.py
index 741727e34..f97acd114 100755
--- a/tests/gclient_scm_test.py
+++ b/tests/gclient_scm_test.py
@@ -161,8 +161,6 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testRunCommandException(self):
     options = self.Options(verbose=False)
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
 
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
@@ -182,8 +180,6 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.scm.SVN.Capture(['--version', '--quiet'], None
         ).AndReturn('1.5.1')
     # It'll to a checkout instead.
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     # Checkout.
     gclient_scm.os.path.exists(self.base_path).AndReturn(False)
     parent = gclient_scm.os.path.dirname(self.base_path)
@@ -212,10 +208,7 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.os.path.isdir(self.base_path).AndReturn(True)
     gclient_scm.os.path.isdir(join(self.base_path, '.svn')).AndReturn(False)
     gclient_scm.os.path.isdir(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.isdir(join(self.base_path, '.hg')).AndReturn(False)
     # Checkout.
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(False)
     parent = gclient_scm.os.path.dirname(self.base_path)
     gclient_scm.os.path.exists(parent).AndReturn(False)
@@ -340,8 +333,6 @@ class SVNWrapperTestCase(BaseTestCase):
     file_info.url = self.url
     file_info.uuid = 'ABC'
     file_info.revision = 42
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     # Checkout.
     gclient_scm.os.path.exists(self.base_path).AndReturn(False)
     parent = gclient_scm.os.path.dirname(self.base_path)
@@ -373,8 +364,8 @@ class SVNWrapperTestCase(BaseTestCase):
       'UUID': 'ABC',
       'Revision': 42,
     }
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
 
     # Checkout or update.
@@ -419,8 +410,8 @@ class SVNWrapperTestCase(BaseTestCase):
       'UUID': 'ABC',
       'Revision': 42,
     }
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
 
     # Checkout or update.
@@ -455,8 +446,8 @@ class SVNWrapperTestCase(BaseTestCase):
       'UUID': 'ABC',
       'Revision': 42,
     }
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
 
     # Checkout or update.
@@ -521,8 +512,8 @@ class SVNWrapperTestCase(BaseTestCase):
         file_list=files_list)
 
     # Now we fall back on scm.update().
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
     gclient_scm.scm.SVN._CaptureInfo([], dotted_path).AndReturn(file_info)
     gclient_scm.scm.SVN._CaptureInfo([file_info['URL']], None
@@ -591,8 +582,8 @@ class SVNWrapperTestCase(BaseTestCase):
         file_list=files_list)
 
     # Now we fall back on scm.update().
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
     gclient_scm.scm.SVN._CaptureInfo(
         [], join(self.base_path, ".")).AndReturn(file_info)
@@ -627,8 +618,8 @@ class SVNWrapperTestCase(BaseTestCase):
 
     # Now we fall back on scm.update().
     files_list = self.mox.CreateMockAnything()
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
     gclient_scm.scm.SVN._CaptureInfo(
         [], join(self.base_path, '.')).AndReturn(file_info)
@@ -644,31 +635,23 @@ class SVNWrapperTestCase(BaseTestCase):
     scm.updatesingle(options, ['DEPS'], files_list)
     self.checkstdout('\n_____ %s at 42\n' % self.relpath)
 
-  def testUpdateGit(self):
+  def testUpdateGitSvn(self):
     options = self.Options(verbose=True)
-    file_path = gclient_scm.os.path.join(self.root_dir, self.relpath, '.git')
-    gclient_scm.os.path.exists(file_path).AndReturn(True)
-
-    self.mox.ReplayAll()
-    scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
-                            relpath=self.relpath)
-    file_list = []
-    scm.update(options, self.args, file_list)
-    self.checkstdout(
-        ('________ found .git directory; skipping %s\n' % self.relpath))
-
-  def testUpdateHg(self):
-    options = self.Options(verbose=True)
-    gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
-    gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(True)
-
+    gclient_scm.os.path.exists(self.base_path).AndReturn(True)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).AndReturn(True)
+    self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'Capture', True)
+    gclient_scm.scm.GIT.Capture(['config', '--local', '--get',
+                                 'svn-remote.svn.url'],
+                                cwd=self.base_path).AndReturn(self.url)
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
                             relpath=self.relpath)
     file_list = []
-    scm.update(options, self.args, file_list)
+    scm.update(options, [], file_list)
     self.checkstdout(
-        ('________ found .hg directory; skipping %s\n' % self.relpath))
+        ('\n_____ %s looks like a git-svn checkout. Skipping.\n' % self.relpath)
+        )
 
   def testGetUsableRevSVN(self):
     # pylint: disable=E1101
@@ -1162,7 +1145,7 @@ class ManagedGitWrapperTestCaseMox(BaseTestCase):
         ).AndReturn(True)
 
     self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
-    gclient_scm.scm.GIT.IsGitSvn(cwd=self.base_path).MultipleTimes(
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).MultipleTimes(
         ).AndReturn(False)
 
     gclient_scm.scm.os.path.isdir(self.base_path).AndReturn(True)
@@ -1211,7 +1194,7 @@ class ManagedGitWrapperTestCaseMox(BaseTestCase):
     gclient_scm.scm.GIT.Capture(['fetch', 'origin'], cwd=self.base_path)
 
     self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsGitSvn', True)
-    gclient_scm.scm.GIT.IsGitSvn(cwd=self.base_path).MultipleTimes(
+    gclient_scm.scm.GIT.IsGitSvn(self.base_path).MultipleTimes(
         ).AndReturn(True)
 
     self.mox.StubOutWithMock(gclient_scm.scm.GIT, 'IsValidRevision', True)
diff --git a/tests/gclient_smoketest.py b/tests/gclient_smoketest.py
index 427699816..b9766855a 100755
--- a/tests/gclient_smoketest.py
+++ b/tests/gclient_smoketest.py
@@ -109,9 +109,11 @@ class GClientSmokeBase(FakeReposTestBase):
               not re.match(
                   r'_____ [^ ]+ : Attempting rebase onto [0-9a-f]+...',
                   line) and
-              not re.match(r'_____ [^ ]+ at [^ ]+', line)):
-            # The two regexp above are a bit too broad, they are necessary only
-            # for git checkouts.
+              not re.match(r'_____ [^ ]+ at [^ ]+', line) and not
+              re.match(
+                  r'_____ (.*) looks like a git-svn checkout. Skipping.',
+                  line)):
+            # The regexp above are a bit too broad.
             self.fail(line)
         else:
           results.append([[match.group(1), match.group(2), match.group(3)]])
@@ -776,7 +778,59 @@ class GClientSmokeSVN(GClientSmokeBase):
 
     # Cripple src/third_party/foo and make sure gclient still succeeds.
     gclient_utils.rmtree(join(third_party, 'foo', '.svn'))
-    self.assertEquals(0, self.gclient(cmd)[-1])
+    self.assertEquals(0, self.gclient(cmd + ['--force'])[-1])
+
+  def testSkipGitSvn(self):
+    # Check that gclient skips git-svn checkouts.
+    if not self.enabled:
+      return
+
+    # Create the .gclient file.
+    svn_url = self.svn_base + 'trunk/src'
+    self.gclient(['config', svn_url], cwd=self.root_dir)
+
+    # Create a git-svn checkout.
+    # Use check_output to hide the output from the subprocess.
+    subprocess2.check_output(['git', 'svn', 'clone', svn_url],
+                             cwd=self.root_dir)
+
+    # Ensure that gclient skips the git-svn checkout.
+    stdout, stderr, rc = self.gclient(['sync', '--jobs', '1'])
+    self.assertEquals(rc, 0)
+    self.assertFalse(stderr)
+    self.assertTrue('_____ src looks like a git-svn checkout. Skipping.'
+                    in stdout)
+    self.checkBlock(stdout, [
+        ['running', self.root_dir],
+        ['running', os.path.join(self.root_dir, 'src', 'file', 'other')],
+        ['running', self.root_dir],
+        ['running', self.root_dir],
+        ['running', self.root_dir],
+        ['running', self.root_dir],
+        ['running', self.root_dir],
+    ])
+
+    # But, we still need the DEPS to be checked out...
+    foo_dir = os.path.join(self.root_dir, 'src', 'third_party', 'foo')
+    foo_rev = subprocess2.check_output(['svnversion', foo_dir]).strip()
+    self.assertEquals(foo_rev, '1')
+
+    other_dir = os.path.join(self.root_dir, 'src', 'other')
+    other_rev = subprocess2.check_output(['svnversion', other_dir]).strip()
+    self.assertEquals(other_rev, '2')
+
+    # Verify that the DEPS are NOT skipped on a second update.
+    stdout, stderr, rc = self.gclient(['sync', '--jobs', '1'])
+    self.assertFalse(stderr)
+    self.assertTrue('_____ src looks like a git-svn checkout. Skipping.'
+                    in stdout)
+    self.assertFalse(
+        '_____ src/other looks like a git-svn checkout. Skipping.' in stdout,
+        'Non git-svn checkout is incorrectly skipped.')
+    self.assertFalse(
+        '_____ src/third_party/foo looks like a git-svn checkout. Skipping.'
+            in stdout,
+        'Non git-svn checkout is incorrectly skipped.')
 
 
 class GClientSmokeSVNTransitive(GClientSmokeBase):
@@ -1062,7 +1116,7 @@ class GClientSmokeGIT(GClientSmokeBase):
     self.assertTree(tree)
 
     # Pre-DEPS hooks run when syncing with --nohooks.
-    self.gclient(['sync', '--deps', 'mac', '--nohooks',
+    self.gclient(['sync', '--deps', 'mac', '--nohooks', '--force',
                   '--revision', 'src@' + self.githash('repo_5', 2)])
     tree = self.mangle_git_tree(('repo_5@2', 'src'),
                                 ('repo_1@2', 'src/repo1'),
@@ -1074,7 +1128,7 @@ class GClientSmokeGIT(GClientSmokeBase):
     os.remove(join(self.root_dir, 'src', 'git_pre_deps_hooked'))
 
     # Pre-DEPS hooks don't run with --noprehooks
-    self.gclient(['sync', '--deps', 'mac', '--noprehooks',
+    self.gclient(['sync', '--deps', 'mac', '--noprehooks', '--force',
                   '--revision', 'src@' + self.githash('repo_5', 2)])
     tree = self.mangle_git_tree(('repo_5@2', 'src'),
                                 ('repo_1@2', 'src/repo1'),
@@ -1396,6 +1450,78 @@ class GClientSmokeBoth(GClientSmokeBase):
 
     self.assertEquals(sorted(entries), sorted(expected))
 
+  if gclient_utils.enable_deletion_of_conflicting_checkouts():
+    def testDeleteConflictingCheckout(self):
+      if not self.enabled:
+        return
+  
+      # Create an initial svn checkout.
+      self.gclient(['config', '--spec',
+          'solutions=['
+          '{"name": "src",'
+          ' "url": "' + self.svn_base + 'trunk/src"},'
+          ']'
+      ])
+      results = self.gclient(['sync', '--deps', 'mac'])
+      self.assertEqual(results[2], 0, 'Sync failed!')
+  
+      # Verify that we have the expected svn checkout.
+      results = self.gclient(['revinfo', '--deps', 'mac'])
+      actual = results[0].splitlines()
+      expected = [
+        'src: %strunk/src' % self.svn_base,
+        'src/file/other: File("%strunk/other/DEPS")' % self.svn_base,
+        'src/other: %strunk/other' % self.svn_base,
+        'src/third_party/foo: %strunk/third_party/foo@1' % self.svn_base,
+      ]
+      self.assertEquals(actual, expected)
+  
+      # Change the desired checkout to git.
+      self.gclient(['config', '--spec',
+          'solutions=['
+          '{"name": "src",'
+          ' "url": "' + self.git_base + 'repo_1"},'
+          ']'
+      ])
+  
+      # Verify that the sync succeeds with --force.
+      results = self.gclient(['sync', '--deps', 'mac', '--force'])
+      self.assertEqual(results[2], 0, 'Sync failed!')
+  
+      # Verify that we got the desired git checkout.
+      results = self.gclient(['revinfo', '--deps', 'mac'])
+      actual = results[0].splitlines()
+      expected = [
+        'src: %srepo_1' % self.git_base,
+        'src/repo2: %srepo_2@%s' % (self.git_base,
+                                    self.githash('repo_2', 1)[:7]),
+        'src/repo2/repo_renamed: %srepo_3' % self.git_base,
+      ]
+      self.assertEquals(actual, expected)
+  
+      # Change the desired checkout back to svn.
+      self.gclient(['config', '--spec',
+          'solutions=['
+          '{"name": "src",'
+          ' "url": "' + self.svn_base + 'trunk/src"},'
+          ']'
+      ])
+  
+      # Verify that the sync succeeds.
+      results = self.gclient(['sync', '--deps', 'mac', '--force'])
+      self.assertEqual(results[2], 0, 'Sync failed!')
+  
+      # Verify that we have the expected svn checkout.
+      results = self.gclient(['revinfo', '--deps', 'mac'])
+      actual = results[0].splitlines()
+      expected = [
+        'src: %strunk/src' % self.svn_base,
+        'src/file/other: File("%strunk/other/DEPS")' % self.svn_base,
+        'src/other: %strunk/other' % self.svn_base,
+        'src/third_party/foo: %strunk/third_party/foo@1' % self.svn_base,
+      ]
+      self.assertEquals(actual, expected)
+
 
 class GClientSmokeFromCheckout(GClientSmokeBase):
   # WebKit abuses this. It has a .gclient and a DEPS from a checkout.
diff --git a/tests/gclient_utils_test.py b/tests/gclient_utils_test.py
index b0b743631..6be9e1f5f 100755
--- a/tests/gclient_utils_test.py
+++ b/tests/gclient_utils_test.py
@@ -29,7 +29,9 @@ class GclientUtilsUnittest(GclientUtilBase):
   def testMembersChanged(self):
     members = [
         'Annotated', 'AutoFlush', 'CheckCallAndFilter', 'CommandToStr',
-        'CheckCallAndFilterAndHeader', 'Error', 'ExecutionQueue', 'FileRead',
+        'CheckCallAndFilterAndHeader',
+        'enable_deletion_of_conflicting_checkouts', # TODO(borenet): Remove!
+        'Error', 'ExecutionQueue', 'FileRead',
         'FileWrite', 'FindFileUpwards', 'FindGclientRoot',
         'GetGClientRootAndEntries', 'GetEditor', 'GetExeSuffix',
         'GetMacWinOrLinux', 'GitFilter', 'IsDateRevision', 'MakeDateRevision',
@@ -39,7 +41,9 @@ class GclientUtilsUnittest(GclientUtilBase):
         'GCLIENT_CHILDREN_LOCK', 'GClientChildren', 'SplitUrlRevision',
         'SyntaxErrorToError', 'UpgradeToHttps', 'Wrapper', 'WorkItem',
         'codecs', 'lockedmethod', 'logging', 'os', 'pipes', 'Queue', 're',
-        'rmtree', 'safe_makedirs', 'safe_rename', 'stat', 'subprocess',
+        'rmtree', 'safe_makedirs', 'safe_rename',
+        'socket', # TODO(borenet): Remove!
+        'stat', 'subprocess',
         'subprocess2', 'sys', 'tempfile', 'threading', 'time', 'urlparse',
 
     ]
diff --git a/tests/scm_unittest.py b/tests/scm_unittest.py
index ff03c03e1..2a1de5331 100755
--- a/tests/scm_unittest.py
+++ b/tests/scm_unittest.py
@@ -169,6 +169,18 @@ class RealGitSvnTest(fake_repos.FakeReposTestBase):
     self._capture(['reset', '--hard', 'HEAD^'])
     self.assertEquals(scm.GIT.GetGitSvnHeadRev(cwd=self.clone_dir), 1)
 
+  def testIsGitSvn(self):
+    if not self.enabled:
+      return
+    # Git-svn
+    self.assertTrue(scm.GIT.IsGitSvn(self.clone_dir))
+    # Pure git
+    git_dir = scm.os.path.join(self.FAKE_REPOS.git_root, 'repo_1')
+    self.assertFalse(scm.GIT.IsGitSvn(git_dir))
+    # Pure svn
+    svn_dir = scm.os.path.join(self.FAKE_REPOS.svn_checkout, 'trunk')
+    self.assertFalse(scm.GIT.IsGitSvn(svn_dir))
+
   def testParseGitSvnSha1(self):
     test_sha1 = 'a5c63ce8671922e5c59c0dea49ef4f9d4a3020c9'
     expected_output = test_sha1 + '\n'