Fix SCM.ReadRootFile when self.gclient_root is not yet defined

trychange.py

 #!/usr/bin/python
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Client-side script to send a try job to the try server. It communicates to
 the try server by either writting to a svn repository or by directly connecting
 to the server by HTTP.
 """
 
 import datetime
@@ skipping 140 matching lines @@
     self._GclientStyleSettings()
     self._GclStyleSettings()
 
   def ReadRootFile(self, filename):
     if not self.options.root:
       filepath = os.path.join(self.checkout_root, filename)
       if os.path.isfile(filepath):
         logging.info('Found %s at %s' % (filename, self.checkout_root))
         return gclient_util.FileRead(filepath)
       return None
-    root = os.path.abspath(self.gclient_root)
     cur = os.path.abspath(self.checkout_root)
+    if self.gclient_root:
+      root = os.path.abspath(self.gclient_root)
+    else:
+      root = gclient_utils.FindGclientRoot(cur)

[M-A Ruel, 2010/05/15 00:53:14]

As I wrote earlier, I still prefer to use root = cur since if you specify a
root, you usually don't want it to mess with interwinded checkouts.

     assert cur.startswith(root), (root, cur)
     while cur.startswith(root):
       filepath = os.path.join(cur, filename)
       if os.path.isfile(filepath):
         logging.info('Found %s at %s' % (filename, cur))
         return gclient_utils.FileRead(filepath)
       cur = os.path.dirname(cur)
     logging.warning('Didn\'t find %s' % filename)
     return None
 
@@ skipping 545 matching lines @@
   except (InvalidScript, NoTryServerAccess), e:
     if swallow_exception:
       return 1
     print e
     return 1
   return 0
 
 
 if __name__ == "__main__":
   sys.exit(TryChange(None, [], False))