Check that directory named depot_tools appears to be full checkout

tools/find_depot_tools.py

 # Copyright (c) 2011 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.
 """Small utility function to find depot_tools and add it to the python path.
 
 Will throw an ImportError exception if depot_tools can't be found since it
 imports breakpad.
 """
 
 import os
 import sys
 
+
+def IsRealDepotTools(path):
+  return os.path.isfile(os.path.join(path, 'breakpad.py'))
+
+
 def add_depot_tools_to_path():
   """Search for depot_tools and add it to sys.path."""
   # First look if depot_tools is already in PYTHONPATH.
   for i in sys.path:
-    if i.rstrip(os.sep).endswith('depot_tools'):
+    if i.rstrip(os.sep).endswith('depot_tools') and IsRealDepotTools(i):
       return i
   # Then look if depot_tools is in PATH, common case.
   for i in os.environ['PATH'].split(os.pathsep):
-    if i.rstrip(os.sep).endswith('depot_tools'):
+    if i.rstrip(os.sep).endswith('depot_tools') and IsRealDepotTools(i):
       sys.path.append(i.rstrip(os.sep))
       return i
   # Rare case, it's not even in PATH, look upward up to root.
   root_dir = os.path.dirname(os.path.abspath(__file__))
   previous_dir = os.path.abspath(__file__)
   while root_dir and root_dir != previous_dir:
-    if os.path.isfile(os.path.join(root_dir, 'depot_tools', 'breakpad.py')):
+    if IsRealDepotTools(os.path.join(root_dir, 'depot_tools')):
       i = os.path.join(root_dir, 'depot_tools')

[Paweł Hajdan Jr., 2014/01/22 03:27:30]

While you're here, let's deduplicate "os.path.join(root_dir, 'depot_tools')" (it
appears in the "if" line 33, and assignment line 34).

[scottmg, 2014/01/22 05:05:36]

Done.

       sys.path.append(i)
       return i
     previous_dir = root_dir
     root_dir = os.path.dirname(root_dir)
   print >> sys.stderr, 'Failed to find depot_tools'
   return None
 
 add_depot_tools_to_path()
 
 # pylint: disable=W0611
 import breakpad