Refactor persisting state in push and merge scripts.

tools/push-to-trunk/auto_roll.py

 #!/usr/bin/env python
 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
@@ skipping 65 matching lines @@
         self.Die("Push to trunk disabled by auto-roll settings file: %s"
                  % settings_file)
 
 
 class CheckTreeStatus(Step):
   MESSAGE = "Checking v8 tree status message."
 
   def RunStep(self):
     status_url = "https://v8-status.appspot.com/current?format=json"
     status_json = self.ReadURL(status_url, wait_plan=[5, 20, 300, 300])
-    message = json.loads(status_json)["message"]
-    if re.search(r"nopush|no push", message, flags=re.I):
-      self.Die("Push to trunk disabled by tree state: %s" % message)
-    self.Persist("tree_message", message)
+    self["tree_message"] = json.loads(status_json)["message"]
+    if re.search(r"nopush|no push", self["tree_message"], flags=re.I):
+      self.Die("Push to trunk disabled by tree state: %s"
+               % self["tree_message"])
 
 
 class FetchLatestRevision(Step):
   MESSAGE = "Fetching latest V8 revision."
 
   def RunStep(self):
     log = self.Git("svn log -1 --oneline").strip()
     match = re.match(r"^r(\d+) ", log)
     if not match:
       self.Die("Could not extract current svn revision from log.")
-    self.Persist("latest", match.group(1))
+    self["latest"] = match.group(1)
 
 
 class CheckLastPush(Step):
   MESSAGE = "Checking last V8 push to trunk."
 
   def RunStep(self):
-    self.RestoreIfUnset("latest")
     log = self.Git("svn log -1 --oneline ChangeLog").strip()
     match = re.match(r"^r(\d+) \| Prepare push to trunk", log)
     if match:
-      latest = int(self._state["latest"])
+      latest = int(self["latest"])
       last_push = int(match.group(1))
       # TODO(machebach): This metric counts all revisions. It could be
       # improved by counting only the revisions on bleeding_edge.
       if latest - last_push < 10:
         # This makes sure the script doesn't push twice in a row when the cron
         # job retries several times.
         self.Die("Last push too recently: %d" % last_push)
 
 
 class FetchLKGR(Step):
   MESSAGE = "Fetching V8 LKGR."
 
   def RunStep(self):
     lkgr_url = "https://v8-status.appspot.com/lkgr"
     # Retry several times since app engine might have issues.
-    self.Persist("lkgr", self.ReadURL(lkgr_url, wait_plan=[5, 20, 300, 300]))
+    self["lkgr"] = self.ReadURL(lkgr_url, wait_plan=[5, 20, 300, 300])
 
 
 class PushToTrunk(Step):
   MESSAGE = "Pushing to trunk if possible."
 
   def PushTreeStatus(self, message):
     if not self._options.status_password:
       print "Skipping tree status update without password file."
       return
     params = {
       "message": message,
       "username": "v8-auto-roll@chromium.org",
       "password": FileToText(self._options.status_password).strip(),
     }
     params = urllib.urlencode(params)
     print "Pushing tree status: '%s'" % message
     self.ReadURL("https://v8-status.appspot.com/status", params,
                  wait_plan=[5, 20])
 
   def RunStep(self):
-    self.RestoreIfUnset("latest")
-    self.RestoreIfUnset("lkgr")
-    self.RestoreIfUnset("tree_message")
-    latest = int(self._state["latest"])
-    lkgr = int(self._state["lkgr"])
+    latest = int(self["latest"])
+    lkgr = int(self["lkgr"])
     if latest == lkgr:
       print "ToT (r%d) is clean. Pushing to trunk." % latest
       self.PushTreeStatus("Tree is closed (preparing to push)")
 
       # TODO(machenbach): Update the script before calling it.
       try:
         if self._options.push:
           self._side_effect_handler.Call(
               RunPushToTrunk,
               push_to_trunk.CONFIG,
               PushToTrunkOptions.MakeForcedOptions(self._options.author,
                                                    self._options.reviewer,
                                                    self._options.c),
               self._side_effect_handler)
       finally:
-        self.PushTreeStatus(self._state["tree_message"])
+        self.PushTreeStatus(self["tree_message"])
     else:
       print("ToT (r%d) is ahead of the LKGR (r%d). Skipping push to trunk."
             % (latest, lkgr))
 
 
 def RunAutoRoll(config,
                 options,
                 side_effect_handler=DEFAULT_SIDE_EFFECT_HANDLER):
   step_classes = [
     Preparation,
@@ skipping 31 matching lines @@
   parser = BuildOptions()
   (options, args) = parser.parse_args()
   if not options.a or not options.c or not options.reviewer:
     print "You need to specify author, chromium src location and reviewer."
     parser.print_help()
     return 1
   RunAutoRoll(CONFIG, AutoRollOptions(options))
 
 if __name__ == "__main__":
   sys.exit(Main())