CrOS: Update public waterfall to auto-configure.

scripts/common/slave_alloc.py

 # Copyright 2015 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.
 
 """Library to generate, maintain, and read static slave pool maps."""
 
 import collections
 import itertools
 import json
 import os
@@ skipping 102 matching lines @@
 
   def LoadState(self, path=None, enforce=True):
     """Loads slave pools from the store, replacing the current in-memory set.
 
     Args:
       path (str): If provided, the path to load from; otherwise,
           DEFAULT_STATE_PATH will be used.
       enforce (bool): If True, raise an IOError if the state file does not
           exist or a ValueError if it could not be loaded.
     """
-    state = None
+    state = {}

[ghost stip (do not use), 2015/04/10 22:47:04]

why is this not None?

[dnj, 2015/04/12 15:20:38]

This handles the case where a state file does not exist.

     path = path or self.DEFAULT_STATE_PATH
     if not os.path.exists(path):
       if enforce:
         raise IOError("State path does not exist: %s" % (path,))
     try:
       with open(path or self.DEFAULT_STATE_PATH, 'r') as fd:
         state = json.load(fd)
     except (IOError, ValueError):
       if enforce:
         raise
@@ skipping 200 matching lines @@
 
     # Convert SlaveMapEntry fields to immutable form.
     result = SlaveMap(
         entries={},
         unallocated=frozenset(n_state.unallocated))
     for k, v in slave_map_entries.iteritems():
       result.entries[k] = SlaveMapEntry(
           classes=frozenset(v.classes),
           keys=tuple(sorted(v.keys)))
     return result