Don't shortcut if we're trying to get the latest copy.

tools/get_archive.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Gets or updates a DumpRenderTree (a nearly headless build of chrome). This is
 # used for running browser tests of client applications.
 
 import json
@@ skipping 287 matching lines @@
 
 def main():
   parser = optparse.OptionParser(usage='usage: %prog [options] download_name')
   parser.add_option('-r', '--revision', dest='revision',
                     help='Desired revision number to retrieve for the SDK. If '
                     'unspecified, retrieve the latest SDK build.',
                     action='store', default=None)
   args, positional = parser.parse_args()
 
   if positional[0] == 'dartium':
-    if args.revision < 4285:
+    if args.revision and args.revision < 4285:

[vsm, 2012/08/20 15:24:45]

Consider keeping a table of latest revisions keyed by name at the top.  Then you
could hoist these checks once as:

if args.revision and args.revision < LAST_VALID[positional[0]]:
  ...

       return too_early_error()
     get_dartium_revision('Dartium', DARTIUM_DIR, DARTIUM_VERSION,
                          DARTIUM_LATEST_PATTERN, DARTIUM_PERMANENT_PATTERN,
                          args.revision)
   elif positional[0] == 'chromedriver':
-    if args.revision < 7823:
+    if args.revision and args.revision < 7823:
       return too_early_error()
     get_dartium_revision('chromedriver', CHROMEDRIVER_DIR, CHROMEDRIVER_VERSION,
                          CHROMEDRIVER_LATEST_PATTERN,
                          CHROMEDRIVER_PERMANENT_PATTERN, args.revision)
   elif positional[0] == 'sdk':
-    if args.revision < 9761:
+    if args.revision and args.revision < 9761:
       return too_early_error()
     get_sdk_revision('sdk', SDK_DIR, SDK_VERSION, SDK_LATEST_PATTERN,
         SDK_PERMANENT, args.revision)
   elif positional[0] == 'drt':
-    if args.revision < 5342:
+    if args.revision and args.revision < 5342:
       return too_early_error()
     get_dartium_revision('DumpRenderTree', DRT_DIR, DRT_VERSION,
                          DRT_LATEST_PATTERN, DRT_PERMANENT_PATTERN,
                          args.revision)
   else:
     print ('Please specify the target you wish to download from Google Storage '
         '("drt", "dartium", "chromedriver", or "sdk")')
 
 if __name__ == '__main__':
   sys.exit(main())