In the chroot, don't do any path mucking. Just run chromite.

bin/chromite

 #!/usr/bin/python
 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Wrapper for the chromite shell.
 
 This script is intended to run in several ways:
 - Outside the chroot, it should be _copied_ to someplace that is in the
   path (like depot_tools).  It will search for the right chromite by looking
@@ skipping 12 matching lines @@
 
 """
 
 # Python imports.
 import os
 import sys
 
 def Search(path):
   """Return an iterator of lists of places to look for chromite."""
 
-  # Look in $CROS_WORKON_SRCROOT first.
-  if 'CROS_WORKON_SRCROOT' in os.environ:
-    yield [os.environ['CROS_WORKON_SRCROOT']]
+  if os.path.exists('/etc/debian_chroot'):
+    # We're in the chroot.  Chromite should be in the python path inside the
+    # chroot, so we don't do any searching.  NOTE that we purposely don't want
+    # CROS_WORKON_SRCROOT in the python path.
+    yield []
+  else:
+    # Look in $CROS_WORKON_SRCROOT first.  The idea is that a user would set
+    # this manually if they wanted to specify a particular version of chromite.
+    if 'CROS_WORKON_SRCROOT' in os.environ:
+      yield [os.environ['CROS_WORKON_SRCROOT']]
 
-  # Try the path as is
-  yield []
-
-  # Search upward until we either end up with a blank dir or the "parent" dir
-  # doesn't change.
-  prev_path = None
-  while path and path != prev_path:
-    yield [path]
-    path, prev_path = os.path.dirname(path), path
+    # Search upward until we either end up with a blank dir or the "parent" dir
+    # doesn't change.
+    prev_path = None
+    while path and path != prev_path:
+      yield [path]
+      path, prev_path = os.path.dirname(path), path
 
 
 for path in Search(os.getcwd()):
   sys.path = path + sys.path

[jrbarnette, 2011/02/07 19:51:23]

I just now noticed this, though I should have noticed before:  I believe
this will cause sys.path gradually to accumulate all the paths yielded up
by Search(), whether or not the path is needed.  I don't think that's right:
we should add only one directory to the path (the one that actually turned
out to be the one we needed).

[diandersAtChromium, 2011/02/07 21:31:02]

It looks like the paths are deleted in the "except ImportError" case.  See
below.  Does that look OK?

   try:
     import chromite.shell.main
     break
   except ImportError, e:
     # We've got different modules named chromite in the tree, pulling in the
     # wrong one will break the right one.  So unload it.
     if 'chromite' in sys.modules:
       del sys.modules['chromite']
     sys.path = sys.path[len(path):]

[diandersAtChromium, 2011/02/07 21:31:02]

Paths are deleted here.

[jrbarnette, 2011/02/08 00:46:06]

Ah, I missed this.

 else:
   # TODO(dianders): Should we actually print out the 'repo init' call that
   # the user should use?
   sys.stderr.write(
       "ERROR: Couldn't find the chromite tool.\n"
       "\n"
       "Please change to a directory inside your Chromium OS source tree\n"
       "and retry.  If you need to setup a Chromium OS source tree, see:\n"
       "  http://www.chromium.org/chromium-os/developer-guide\n")
   sys.exit(1)
 
 chromite.shell.main.main()