From: machenbach@chromium.org <machenbach@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Wed, 19 Feb 2014 11:56:48 +0000 (+0000)
Subject: Refactor persisting state in push and merge scripts.
X-Git-Tag: upstream/4.7.83~10621
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a56d0da6238b0f4b20ccd83bcfdc777654c0ce9b;p=platform%2Fupstream%2Fv8.git

Refactor persisting state in push and merge scripts.

- The backed state dict is now persisted and restored in the step template as a json file
- All explicit persist/restore calls are removed
- Added testing an unexpected script failure + restart with state recovery to the merge-to-branch test
- This CL is not changing external behavior of the scripts

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/170583002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19478 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---

diff --git a/tools/push-to-trunk/auto_roll.py b/tools/push-to-trunk/auto_roll.py
index 086f5a8..d147f86 100755
--- a/tools/push-to-trunk/auto_roll.py
+++ b/tools/push-to-trunk/auto_roll.py
@@ -83,10 +83,10 @@ class CheckTreeStatus(Step):
   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):
@@ -97,18 +97,17 @@ class FetchLatestRevision(Step):
     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.
@@ -124,7 +123,7 @@ class FetchLKGR(Step):
   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):
@@ -145,11 +144,8 @@ class PushToTrunk(Step):
                  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)")
@@ -165,7 +161,7 @@ class PushToTrunk(Step):
                                                    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))
diff --git a/tools/push-to-trunk/common_includes.py b/tools/push-to-trunk/common_includes.py
index f1d5e50..e5f5c59 100644
--- a/tools/push-to-trunk/common_includes.py
+++ b/tools/push-to-trunk/common_includes.py
@@ -27,6 +27,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import datetime
+import json
 import os
 import re
 import subprocess
@@ -246,17 +247,35 @@ class Step(object):
     assert self._side_effect_handler is not None
     assert isinstance(options, CommonOptions)
 
+  def __getitem__(self, key):
+    # Convenience method to allow direct [] access on step classes for
+    # manipulating the backed state dict.
+    return self._state[key]
+
+  def __setitem__(self, key, value):
+    # Convenience method to allow direct [] access on step classes for
+    # manipulating the backed state dict.
+    self._state[key] = value
+
   def Config(self, key):
     return self._config[key]
 
   def Run(self):
-    if self._requires:
-      self.RestoreIfUnset(self._requires)
-      if not self._state[self._requires]:
-        return
+    # Restore state.
+    state_file = "%s-state.json" % self._config[PERSISTFILE_BASENAME]
+    if not self._state and os.path.exists(state_file):
+      self._state.update(json.loads(FileToText(state_file)))
+
+    # Skip step if requirement is not met.
+    if self._requires and not self._state.get(self._requires):
+      return
+
     print ">>> Step %d: %s" % (self._number, self._text)
     self.RunStep()
 
+    # Persist state.
+    TextToFile(json.dumps(self._state), state_file)
+
   def RunStep(self):
     raise NotImplementedError
 
@@ -349,19 +368,6 @@ class Step(object):
           msg = "Can't continue. Please delete branch %s and try again." % name
           self.Die(msg)
 
-  def Persist(self, var, value):
-    value = value or "__EMPTY__"
-    TextToFile(value, "%s-%s" % (self._config[PERSISTFILE_BASENAME], var))
-
-  def Restore(self, var):
-    value = FileToText("%s-%s" % (self._config[PERSISTFILE_BASENAME], var))
-    value = value or self.Die("Variable '%s' could not be restored." % var)
-    return "" if value == "__EMPTY__" else value
-
-  def RestoreIfUnset(self, var_name):
-    if self._state.get(var_name) is None:
-      self._state[var_name] = self.Restore(var_name)
-
   def InitialEnvironmentChecks(self):
     # Cancel if this is not a git checkout.
     if not os.path.exists(self._config[DOT_GIT_LOCATION]):
@@ -378,14 +384,13 @@ class Step(object):
       self.Die("Workspace is not clean. Please commit or undo your changes.")
 
     # Persist current branch.
-    current_branch = ""
+    self["current_branch"] = ""
     git_result = self.Git("status -s -b -uno").strip()
     for line in git_result.splitlines():
       match = re.match(r"^## (.+)", line)
       if match:
-        current_branch = match.group(1)
+        self["current_branch"] = match.group(1)
         break
-    self.Persist("current_branch", current_branch)
 
     # Fetch unfetched revisions.
     if self.Git("svn fetch") is None:
@@ -393,8 +398,7 @@ class Step(object):
 
   def PrepareBranch(self):
     # Get ahold of a safe temporary branch and check it out.
-    self.RestoreIfUnset("current_branch")
-    if self._state["current_branch"] != self._config[TEMP_BRANCH]:
+    if self["current_branch"] != self._config[TEMP_BRANCH]:
       self.DeleteBranch(self._config[TEMP_BRANCH])
       self.Git("checkout -b %s" % self._config[TEMP_BRANCH])
 
@@ -402,11 +406,10 @@ class Step(object):
     self.DeleteBranch(self._config[BRANCHNAME])
 
   def CommonCleanup(self):
-    self.RestoreIfUnset("current_branch")
-    self.Git("checkout -f %s" % self._state["current_branch"])
-    if self._config[TEMP_BRANCH] != self._state["current_branch"]:
+    self.Git("checkout -f %s" % self["current_branch"])
+    if self._config[TEMP_BRANCH] != self["current_branch"]:
       self.Git("branch -D %s" % self._config[TEMP_BRANCH])
-    if self._config[BRANCHNAME] != self._state["current_branch"]:
+    if self._config[BRANCHNAME] != self["current_branch"]:
       self.Git("branch -D %s" % self._config[BRANCHNAME])
 
     # Clean up all temporary files.
@@ -417,8 +420,7 @@ class Step(object):
       match = re.match(r"^#define %s\s+(\d*)" % def_name, line)
       if match:
         value = match.group(1)
-        self.Persist("%s%s" % (prefix, var_name), value)
-        self._state["%s%s" % (prefix, var_name)] = value
+        self["%s%s" % (prefix, var_name)] = value
     for line in LinesInFile(self._config[VERSION_FILE]):
       for (var_name, def_name) in [("major", "MAJOR_VERSION"),
                                    ("minor", "MINOR_VERSION"),
@@ -426,10 +428,6 @@ class Step(object):
                                    ("patch", "PATCH_LEVEL")]:
         ReadAndPersist(var_name, def_name)
 
-  def RestoreVersionIfUnset(self, prefix=""):
-    for v in ["major", "minor", "build", "patch"]:
-      self.RestoreIfUnset("%s%s" % (prefix, v))
-
   def WaitForLGTM(self):
     print ("Please wait for an LGTM, then type \"LGTM<Return>\" to commit "
            "your change. (If you need to iterate on the patch or double check "
@@ -509,6 +507,9 @@ def RunScript(step_classes,
               config,
               options,
               side_effect_handler=DEFAULT_SIDE_EFFECT_HANDLER):
+  state_file = "%s-state.json" % config[PERSISTFILE_BASENAME]
+  if options.s == 0 and os.path.exists(state_file):
+    os.remove(state_file)
   state = {}
   steps = []
   for (number, step_class) in enumerate(step_classes):
diff --git a/tools/push-to-trunk/merge_to_branch.py b/tools/push-to-trunk/merge_to_branch.py
index 7d5f53f..8e126b1 100755
--- a/tools/push-to-trunk/merge_to_branch.py
+++ b/tools/push-to-trunk/merge_to_branch.py
@@ -76,9 +76,9 @@ class Preparation(Step):
 
     self.InitialEnvironmentChecks()
     if self._options.revert_bleeding_edge:
-      self.Persist("merge_to_branch", "bleeding_edge")
+      self["merge_to_branch"] = "bleeding_edge"
     elif self._options.args[0]:
-      self.Persist("merge_to_branch", self._options.args[0])
+      self["merge_to_branch"] = self._options.args[0]
       self._options.args = self._options.args[1:]
     else:
       self.Die("Please specify a branch to merge to")
@@ -91,9 +91,8 @@ class CreateBranch(Step):
   MESSAGE = "Create a fresh branch for the patch."
 
   def RunStep(self):
-    self.RestoreIfUnset("merge_to_branch")
     args = "checkout -b %s svn/%s" % (self.Config(BRANCHNAME),
-                                      self._state["merge_to_branch"])
+                                      self["merge_to_branch"])
     if self.Git(args) is None:
       self.die("Creating branch %s failed." % self.Config(BRANCHNAME))
 
@@ -102,9 +101,9 @@ class SearchArchitecturePorts(Step):
   MESSAGE = "Search for corresponding architecture ports."
 
   def RunStep(self):
-    full_revision_list = list(OrderedDict.fromkeys(self._options.args))
+    self["full_revision_list"] = list(OrderedDict.fromkeys(self._options.args))
     port_revision_list = []
-    for revision in full_revision_list:
+    for revision in self["full_revision_list"]:
       # Search for commits which matches the "Port rXXX" pattern.
       args = ("log svn/bleeding_edge --reverse "
               "--format=%%H --grep=\"Port r%d\"" % int(revision))
@@ -117,7 +116,7 @@ class SearchArchitecturePorts(Step):
         revision_title = self.Git("log -1 --format=%%s %s" % git_hash)
 
         # Is this revision included in the original revision list?
-        if svn_revision in full_revision_list:
+        if svn_revision in self["full_revision_list"]:
           print("Found port of r%s -> r%s (already included): %s"
                 % (revision, svn_revision, revision_title))
         else:
@@ -130,76 +129,61 @@ class SearchArchitecturePorts(Step):
       if self.Confirm("Automatically add corresponding ports (%s)?"
                       % ", ".join(port_revision_list)):
         #: 'y': Add ports to revision list.
-        full_revision_list.extend(port_revision_list)
-    self.Persist("full_revision_list", ",".join(full_revision_list))
+        self["full_revision_list"].extend(port_revision_list)
 
 
 class FindGitRevisions(Step):
   MESSAGE = "Find the git revisions associated with the patches."
 
   def RunStep(self):
-    self.RestoreIfUnset("full_revision_list")
-    self.RestoreIfUnset("merge_to_branch")
-    full_revision_list = self._state["full_revision_list"].split(",")
-    patch_commit_hashes = []
-    for revision in full_revision_list:
+    self["patch_commit_hashes"] = []
+    for revision in self["full_revision_list"]:
       next_hash = self.Git("svn find-rev \"r%s\" svn/bleeding_edge" % revision)
       if not next_hash:
         self.Die("Cannot determine git hash for r%s" % revision)
-      patch_commit_hashes.append(next_hash)
+      self["patch_commit_hashes"].append(next_hash)
 
     # Stringify: [123, 234] -> "r123, r234"
-    revision_list = ", ".join(map(lambda s: "r%s" % s, full_revision_list))
+    self["revision_list"] = ", ".join(map(lambda s: "r%s" % s,
+                                      self["full_revision_list"]))
 
-    if not revision_list:
+    if not self["revision_list"]:
       self.Die("Revision list is empty.")
 
     if self._options.revert:
       if not self._options.revert_bleeding_edge:
-        new_commit_msg = ("Rollback of %s in %s branch."
-                          % (revision_list, self._state["merge_to_branch"]))
+        self["new_commit_msg"] = ("Rollback of %s in %s branch."
+            % (self["revision_list"], self["merge_to_branch"]))
       else:
-        new_commit_msg = "Revert %s ." % revision_list
+        self["new_commit_msg"] = "Revert %s." % self["revision_list"]
     else:
-      new_commit_msg = ("Merged %s into %s branch."
-                        % (revision_list, self._state["merge_to_branch"]))
-    new_commit_msg += "\n\n"
+      self["new_commit_msg"] = ("Merged %s into %s branch."
+          % (self["revision_list"], self["merge_to_branch"]))
+    self["new_commit_msg"] += "\n\n"
 
-    for commit_hash in patch_commit_hashes:
+    for commit_hash in self["patch_commit_hashes"]:
       patch_merge_desc = self.Git("log -1 --format=%%s %s" % commit_hash)
-      new_commit_msg += "%s\n\n" % patch_merge_desc.strip()
+      self["new_commit_msg"] += "%s\n\n" % patch_merge_desc.strip()
 
     bugs = []
-    for commit_hash in patch_commit_hashes:
+    for commit_hash in self["patch_commit_hashes"]:
       msg = self.Git("log -1 %s" % commit_hash)
       for bug in re.findall(r"^[ \t]*BUG[ \t]*=[ \t]*(.*?)[ \t]*$", msg,
                             re.M):
         bugs.extend(map(lambda s: s.strip(), bug.split(",")))
     bug_aggregate = ",".join(sorted(bugs))
     if bug_aggregate:
-      new_commit_msg += "BUG=%s\nLOG=N\n" % bug_aggregate
-    TextToFile(new_commit_msg, self.Config(COMMITMSG_FILE))
-    self.Persist("new_commit_msg", new_commit_msg)
-    self.Persist("revision_list", revision_list)
-    self._state["patch_commit_hashes"] = patch_commit_hashes
-    self.Persist("patch_commit_hashes_list", " ".join(patch_commit_hashes))
+      self["new_commit_msg"] += "BUG=%s\nLOG=N\n" % bug_aggregate
+    TextToFile(self["new_commit_msg"], self.Config(COMMITMSG_FILE))
 
 
 class ApplyPatches(Step):
   MESSAGE = "Apply patches for selected revisions."
 
   def RunStep(self):
-    self.RestoreIfUnset("merge_to_branch")
-    self.RestoreIfUnset("patch_commit_hashes_list")
-    patch_commit_hashes = self._state.get("patch_commit_hashes")
-    if not patch_commit_hashes:
-      patch_commit_hashes = (
-          self._state.get("patch_commit_hashes_list").strip().split(" "))
-    if not patch_commit_hashes and not options.patch:
-      self.Die("Variable patch_commit_hashes could not be restored.")
-    for commit_hash in patch_commit_hashes:
+    for commit_hash in self["patch_commit_hashes"]:
       print("Applying patch for %s to %s..."
-            % (commit_hash, self._state["merge_to_branch"]))
+            % (commit_hash, self["merge_to_branch"]))
       patch = self.Git("log -1 -p %s" % commit_hash)
       TextToFile(patch, self.Config(TEMPORARY_PATCH_FILE))
       self.ApplyPatch(self.Config(TEMPORARY_PATCH_FILE), self._options.revert)
@@ -223,8 +207,7 @@ class IncrementVersion(Step):
   def RunStep(self):
     if self._options.revert_bleeding_edge:
       return
-    self.RestoreIfUnset("patch")
-    new_patch = str(int(self._state["patch"]) + 1)
+    new_patch = str(int(self["patch"]) + 1)
     if self.Confirm("Automatically increment PATCH_LEVEL? (Saying 'n' will "
                     "fire up your EDITOR on %s so you can make arbitrary "
                     "changes. When you're done, save the file and exit your "
@@ -251,7 +234,6 @@ class CommitRepository(Step):
   MESSAGE = "Commit to the repository."
 
   def RunStep(self):
-    self.RestoreIfUnset("merge_to_branch")
     if self.Git("checkout %s" % self.Config(BRANCHNAME)) is None:
       self.Die("Cannot ensure that the current branch is %s"
                % self.Config(BRANCHNAME))
@@ -270,18 +252,16 @@ class PrepareSVN(Step):
   def RunStep(self):
     if self._options.revert_bleeding_edge:
       return
-    self.RestoreIfUnset("new_commit_msg")
-    self.RestoreIfUnset("merge_to_branch")
     if self.Git("svn fetch") is None:
       self.Die("'git svn fetch' failed.")
     args = ("log -1 --format=%%H --grep=\"%s\" svn/%s"
-            % (self._state["new_commit_msg"], self._state["merge_to_branch"]))
+            % (self["new_commit_msg"], self["merge_to_branch"]))
     commit_hash = self.Git(args).strip()
     if not commit_hash:
       self.Die("Unable to map git commit to svn revision.")
-    svn_revision = self.Git("svn find-rev %s" % commit_hash).strip()
-    print "subversion revision number is r%s" % svn_revision
-    self.Persist("svn_revision", svn_revision)
+    self["svn_revision"] = self.Git(
+        "svn find-rev %s" % commit_hash).strip()
+    print "subversion revision number is r%s" % self["svn_revision"]
 
 
 class TagRevision(Step):
@@ -290,45 +270,34 @@ class TagRevision(Step):
   def RunStep(self):
     if self._options.revert_bleeding_edge:
       return
-    self.RestoreVersionIfUnset("new_")
-    self.RestoreIfUnset("svn_revision")
-    self.RestoreIfUnset("merge_to_branch")
-    ver = "%s.%s.%s.%s" % (self._state["new_major"],
-                           self._state["new_minor"],
-                           self._state["new_build"],
-                           self._state["new_patch"])
-    print "Creating tag svn/tags/%s" % ver
-    if self._state["merge_to_branch"] == "trunk":
-      to_url = "trunk"
+    self["version"] = "%s.%s.%s.%s" % (self["new_major"],
+                                       self["new_minor"],
+                                       self["new_build"],
+                                       self["new_patch"])
+    print "Creating tag svn/tags/%s" % self["version"]
+    if self["merge_to_branch"] == "trunk":
+      self["to_url"] = "trunk"
     else:
-      to_url = "branches/%s" % self._state["merge_to_branch"]
+      self["to_url"] = "branches/%s" % self["merge_to_branch"]
     self.SVN("copy -r %s https://v8.googlecode.com/svn/%s "
              "https://v8.googlecode.com/svn/tags/%s -m "
              "\"Tagging version %s\""
-             % (self._state["svn_revision"], to_url, ver, ver))
-    self.Persist("to_url", to_url)
+             % (self["svn_revision"], self["to_url"],
+                self["version"], self["version"]))
 
 
 class CleanUp(Step):
   MESSAGE = "Cleanup."
 
   def RunStep(self):
-    self.RestoreIfUnset("svn_revision")
-    self.RestoreIfUnset("to_url")
-    self.RestoreIfUnset("revision_list")
-    self.RestoreVersionIfUnset("new_")
-    ver = "%s.%s.%s.%s" % (self._state["new_major"],
-                           self._state["new_minor"],
-                           self._state["new_build"],
-                           self._state["new_patch"])
     self.CommonCleanup()
     if not self._options.revert_bleeding_edge:
       print "*** SUMMARY ***"
-      print "version: %s" % ver
-      print "branch: %s" % self._state["to_url"]
-      print "svn revision: %s" % self._state["svn_revision"]
-      if self._state["revision_list"]:
-        print "patches: %s" % self._state["revision_list"]
+      print "version: %s" % self["version"]
+      print "branch: %s" % self["to_url"]
+      print "svn revision: %s" % self["svn_revision"]
+      if self["revision_list"]:
+        print "patches: %s" % self["revision_list"]
 
 
 def RunMergeToBranch(config,
diff --git a/tools/push-to-trunk/push_to_trunk.py b/tools/push-to-trunk/push_to_trunk.py
index 71a037c..fc8399a 100755
--- a/tools/push-to-trunk/push_to_trunk.py
+++ b/tools/push-to-trunk/push_to_trunk.py
@@ -109,8 +109,7 @@ class DetectLastPush(Step):
         break
       args = "log -1 --format=%H %s^ ChangeLog" % last_push
       last_push = self.Git(args).strip()
-    self.Persist("last_push", last_push)
-    self._state["last_push"] = last_push
+    self["last_push"] = last_push
 
 
 class PrepareChangeLog(Step):
@@ -124,7 +123,8 @@ class PrepareChangeLog(Step):
     match = re.search(r"^Review URL: https://codereview\.chromium\.org/(\d+)$",
                       body, flags=re.M)
     if match:
-      cl_url = "https://codereview.chromium.org/%s/description" % match.group(1)
+      cl_url = ("https://codereview.chromium.org/%s/description"
+                % match.group(1))
       try:
         # Fetch from Rietveld but only retry once with one second delay since
         # there might be many revisions.
@@ -134,20 +134,17 @@ class PrepareChangeLog(Step):
     return body
 
   def RunStep(self):
-    self.RestoreIfUnset("last_push")
-
     # These version numbers are used again later for the trunk commit.
     self.ReadAndPersistVersion()
-
-    date = self.GetDate()
-    self.Persist("date", date)
-    output = "%s: Version %s.%s.%s\n\n" % (date,
-                                           self._state["major"],
-                                           self._state["minor"],
-                                           self._state["build"])
+    self["date"] = self.GetDate()
+    self["version"] = "%s.%s.%s" % (self["major"],
+                                    self["minor"],
+                                    self["build"])
+    output = "%s: Version %s\n\n" % (self["date"],
+                                     self["version"])
     TextToFile(output, self.Config(CHANGELOG_ENTRY_FILE))
 
-    args = "log %s..HEAD --format=%%H" % self._state["last_push"]
+    args = "log %s..HEAD --format=%%H" % self["last_push"]
     commits = self.Git(args).strip()
 
     # Cache raw commit messages.
@@ -208,8 +205,7 @@ class IncrementVersion(Step):
   MESSAGE = "Increment version number."
 
   def RunStep(self):
-    self.RestoreIfUnset("build")
-    new_build = str(int(self._state["build"]) + 1)
+    new_build = str(int(self["build"]) + 1)
 
     if self.Confirm(("Automatically increment BUILD_NUMBER? (Saying 'n' will "
                      "fire up your EDITOR on %s so you can make arbitrary "
@@ -230,12 +226,10 @@ class CommitLocal(Step):
   MESSAGE = "Commit to local branch."
 
   def RunStep(self):
-    self.RestoreVersionIfUnset("new_")
-    prep_commit_msg = ("Prepare push to trunk.  "
-        "Now working on version %s.%s.%s." % (self._state["new_major"],
-                                              self._state["new_minor"],
-                                              self._state["new_build"]))
-    self.Persist("prep_commit_msg", prep_commit_msg)
+    self["prep_commit_msg"] = ("Prepare push to trunk.  "
+        "Now working on version %s.%s.%s." % (self["new_major"],
+                                              self["new_minor"],
+                                              self["new_build"]))
 
     # Include optional TBR only in the git command. The persisted commit
     # message is used for finding the commit again later.
@@ -243,7 +237,8 @@ class CommitLocal(Step):
       review = "\n\nTBR=%s" % self._options.reviewer
     else:
       review = ""
-    if self.Git("commit -a -m \"%s%s\"" % (prep_commit_msg, review)) is None:
+    if self.Git("commit -a -m \"%s%s\""
+                % (self["prep_commit_msg"], review)) is None:
       self.Die("'git commit -a' failed.")
 
 
@@ -273,10 +268,8 @@ class StragglerCommits(Step):
     if self.Git("svn fetch") is None:
       self.Die("'git svn fetch' failed.")
     self.Git("checkout svn/bleeding_edge")
-    self.RestoreIfUnset("prep_commit_msg")
-    args = "log -1 --format=%%H --grep=\"%s\"" % self._state["prep_commit_msg"]
-    prepare_commit_hash = self.Git(args).strip()
-    self.Persist("prepare_commit_hash", prepare_commit_hash)
+    args = "log -1 --format=%%H --grep=\"%s\"" % self["prep_commit_msg"]
+    self["prepare_commit_hash"] = self.Git(args).strip()
 
 
 class SquashCommits(Step):
@@ -285,24 +278,22 @@ class SquashCommits(Step):
   def RunStep(self):
     # Instead of relying on "git rebase -i", we'll just create a diff, because
     # that's easier to automate.
-    self.RestoreIfUnset("prepare_commit_hash")
-    args = "diff svn/trunk %s" % self._state["prepare_commit_hash"]
+    args = "diff svn/trunk %s" % self["prepare_commit_hash"]
     TextToFile(self.Git(args), self.Config(PATCH_FILE))
 
     # Convert the ChangeLog entry to commit message format.
-    self.RestoreIfUnset("date")
     text = FileToText(self.Config(CHANGELOG_ENTRY_FILE))
 
     # Remove date and trailing white space.
-    text = re.sub(r"^%s: " % self._state["date"], "", text.rstrip())
+    text = re.sub(r"^%s: " % self["date"], "", text.rstrip())
 
     # Retrieve svn revision for showing the used bleeding edge revision in the
     # commit message.
-    args = "svn find-rev %s" % self._state["prepare_commit_hash"]
-    svn_revision = self.Git(args).strip()
-    self.Persist("svn_revision", svn_revision)
+    args = "svn find-rev %s" % self["prepare_commit_hash"]
+    self["svn_revision"] = self.Git(args).strip()
     text = MSub(r"^(Version \d+\.\d+\.\d+)$",
-                "\\1 (based on bleeding_edge revision r%s)" % svn_revision,
+                ("\\1 (based on bleeding_edge revision r%s)"
+                 % self["svn_revision"]),
                 text)
 
     # Remove indentation and merge paragraphs into single long lines, keeping
@@ -339,15 +330,14 @@ class SetVersion(Step):
   MESSAGE = "Set correct version for trunk."
 
   def RunStep(self):
-    self.RestoreVersionIfUnset()
     output = ""
     for line in FileToText(self.Config(VERSION_FILE)).splitlines():
       if line.startswith("#define MAJOR_VERSION"):
-        line = re.sub("\d+$", self._state["major"], line)
+        line = re.sub("\d+$", self["major"], line)
       elif line.startswith("#define MINOR_VERSION"):
-        line = re.sub("\d+$", self._state["minor"], line)
+        line = re.sub("\d+$", self["minor"], line)
       elif line.startswith("#define BUILD_NUMBER"):
-        line = re.sub("\d+$", self._state["build"], line)
+        line = re.sub("\d+$", self["build"], line)
       elif line.startswith("#define PATCH_LEVEL"):
         line = re.sub("\d+$", "0", line)
       elif line.startswith("#define IS_CANDIDATE_VERSION"):
@@ -386,30 +376,26 @@ class CommitSVN(Step):
     result = filter(lambda x: re.search(r"^Committed r[0-9]+", x),
                     result.splitlines())
     if len(result) > 0:
-      trunk_revision = re.sub(r"^Committed r([0-9]+)", r"\1", result[0])
+      self["trunk_revision"] = re.sub(r"^Committed r([0-9]+)", r"\1",result[0])
 
     # Sometimes grepping for the revision fails. No idea why. If you figure
     # out why it is flaky, please do fix it properly.
-    if not trunk_revision:
+    if not self["trunk_revision"]:
       print("Sorry, grepping for the SVN revision failed. Please look for it "
             "in the last command's output above and provide it manually (just "
             "the number, without the leading \"r\").")
       self.DieNoManualMode("Can't prompt in forced mode.")
-      while not trunk_revision:
+      while not self["trunk_revision"]:
         print "> ",
-        trunk_revision = self.ReadLine()
-    self.Persist("trunk_revision", trunk_revision)
+        self["trunk_revision"] = self.ReadLine()
 
 
 class TagRevision(Step):
   MESSAGE = "Tag the new revision."
 
   def RunStep(self):
-    self.RestoreVersionIfUnset()
-    ver = "%s.%s.%s" % (self._state["major"],
-                        self._state["minor"],
-                        self._state["build"])
-    if self.Git("svn tag %s -m \"Tagging version %s\"" % (ver, ver),
+    if self.Git(("svn tag %s -m \"Tagging version %s\""
+                 % (self["version"], self["version"])),
                 retry_on=lambda x: x is None) is None:
       self.Die("'git svn tag' failed.")
 
@@ -418,16 +404,15 @@ class CheckChromium(Step):
   MESSAGE = "Ask for chromium checkout."
 
   def Run(self):
-    chrome_path = self._options.c
-    if not chrome_path:
+    self["chrome_path"] = self._options.c
+    if not self["chrome_path"]:
       self.DieNoManualMode("Please specify the path to a Chromium checkout in "
                           "forced mode.")
       print ("Do you have a \"NewGit\" Chromium checkout and want "
           "this script to automate creation of the roll CL? If yes, enter the "
           "path to (and including) the \"src\" directory here, otherwise just "
           "press <Return>: "),
-      chrome_path = self.ReadLine()
-    self.Persist("chrome_path", chrome_path)
+      self["chrome_path"] = self.ReadLine()
 
 
 class SwitchChromium(Step):
@@ -435,9 +420,8 @@ class SwitchChromium(Step):
   REQUIRES = "chrome_path"
 
   def RunStep(self):
-    v8_path = os.getcwd()
-    self.Persist("v8_path", v8_path)
-    os.chdir(self._state["chrome_path"])
+    self["v8_path"] = os.getcwd()
+    os.chdir(self["chrome_path"])
     self.InitialEnvironmentChecks()
     # Check for a clean workdir.
     if self.Git("status -s -uno").strip() != "":
@@ -452,14 +436,13 @@ class UpdateChromiumCheckout(Step):
   REQUIRES = "chrome_path"
 
   def RunStep(self):
-    os.chdir(self._state["chrome_path"])
+    os.chdir(self["chrome_path"])
     if self.Git("checkout master") is None:
       self.Die("'git checkout master' failed.")
     if self.Git("pull") is None:
       self.Die("'git pull' failed, please try again.")
 
-    self.RestoreIfUnset("trunk_revision")
-    args = "checkout -b v8-roll-%s" % self._state["trunk_revision"]
+    args = "checkout -b v8-roll-%s" % self["trunk_revision"]
     if self.Git(args) is None:
       self.Die("Failed to checkout a new branch.")
 
@@ -469,20 +452,15 @@ class UploadCL(Step):
   REQUIRES = "chrome_path"
 
   def RunStep(self):
-    os.chdir(self._state["chrome_path"])
+    os.chdir(self["chrome_path"])
 
     # Patch DEPS file.
-    self.RestoreIfUnset("trunk_revision")
     deps = FileToText(self.Config(DEPS_FILE))
     deps = re.sub("(?<=\"v8_revision\": \")([0-9]+)(?=\")",
-                  self._state["trunk_revision"],
+                  self["trunk_revision"],
                   deps)
     TextToFile(deps, self.Config(DEPS_FILE))
 
-    self.RestoreVersionIfUnset()
-    ver = "%s.%s.%s" % (self._state["major"],
-                        self._state["minor"],
-                        self._state["build"])
     if self._options.reviewer:
       print "Using account %s for review." % self._options.reviewer
       rev = self._options.reviewer
@@ -490,10 +468,9 @@ class UploadCL(Step):
       print "Please enter the email address of a reviewer for the roll CL: ",
       self.DieNoManualMode("A reviewer must be specified in forced mode.")
       rev = self.ReadLine()
-    self.RestoreIfUnset("svn_revision")
     args = ("commit -am \"Update V8 to version %s "
             "(based on bleeding_edge revision r%s).\n\nTBR=%s\""
-            % (ver, self._state["svn_revision"], rev))
+            % (self["version"], self["svn_revision"], rev))
     if self.Git(args) is None:
       self.Die("'git commit' failed.")
     author_option = self._options.author
@@ -510,33 +487,27 @@ class SwitchV8(Step):
   REQUIRES = "chrome_path"
 
   def RunStep(self):
-    self.RestoreIfUnset("v8_path")
-    os.chdir(self._state["v8_path"])
+    os.chdir(self["v8_path"])
 
 
 class CleanUp(Step):
   MESSAGE = "Done!"
 
   def RunStep(self):
-    self.RestoreVersionIfUnset()
-    ver = "%s.%s.%s" % (self._state["major"],
-                        self._state["minor"],
-                        self._state["build"])
-    self.RestoreIfUnset("trunk_revision")
-    self.RestoreIfUnset("chrome_path")
-
-    if self._state["chrome_path"]:
+    if self["chrome_path"]:
       print("Congratulations, you have successfully created the trunk "
             "revision %s and rolled it into Chromium. Please don't forget to "
-            "update the v8rel spreadsheet:" % ver)
+            "update the v8rel spreadsheet:" % self["version"])
     else:
       print("Congratulations, you have successfully created the trunk "
             "revision %s. Please don't forget to roll this new version into "
-            "Chromium, and to update the v8rel spreadsheet:" % ver)
-    print "%s\ttrunk\t%s" % (ver, self._state["trunk_revision"])
+            "Chromium, and to update the v8rel spreadsheet:"
+            % self["version"])
+    print "%s\ttrunk\t%s" % (self["version"],
+                             self["trunk_revision"])
 
     self.CommonCleanup()
-    if self.Config(TRUNKBRANCH) != self._state["current_branch"]:
+    if self.Config(TRUNKBRANCH) != self["current_branch"]:
       self.Git("branch -D %s" % self.Config(TRUNKBRANCH))
 
 
diff --git a/tools/push-to-trunk/test_scripts.py b/tools/push-to-trunk/test_scripts.py
index 242efba..668ced6 100644
--- a/tools/push-to-trunk/test_scripts.py
+++ b/tools/push-to-trunk/test_scripts.py
@@ -298,6 +298,7 @@ class ScriptTest(unittest.TestCase):
   def MakeStep(self, step_class=Step, state=None, options=None):
     """Convenience wrapper."""
     options = options or CommonOptions(MakeOptions())
+    state = state if state is not None else self._state
     return MakeStep(step_class=step_class, number=0, state=state,
                     config=TEST_CONFIG, options=options,
                     side_effect_handler=self)
@@ -356,6 +357,7 @@ class ScriptTest(unittest.TestCase):
     self._rl_mock = SimpleMock("readline")
     self._url_mock = SimpleMock("readurl")
     self._tmp_files = []
+    self._state = {}
 
   def tearDown(self):
     Command("rm", "-rf %s*" % TEST_CONFIG[PERSISTFILE_BASENAME])
@@ -369,12 +371,6 @@ class ScriptTest(unittest.TestCase):
     self._rl_mock.AssertFinished()
     self._url_mock.AssertFinished()
 
-  def testPersistRestore(self):
-    self.MakeStep().Persist("test1", "")
-    self.assertEquals("", self.MakeStep().Restore("test1"))
-    self.MakeStep().Persist("test2", "AB123")
-    self.assertEquals("AB123", self.MakeStep().Restore("test2"))
-
   def testGitOrig(self):
     self.assertTrue(Command("git", "--version").startswith("git version"))
 
@@ -396,7 +392,7 @@ class ScriptTest(unittest.TestCase):
     self.ExpectReadline(["Y"])
     self.MakeStep().CommonPrepare()
     self.MakeStep().PrepareBranch()
-    self.assertEquals("some_branch", self.MakeStep().Restore("current_branch"))
+    self.assertEquals("some_branch", self._state["current_branch"])
 
   def testCommonPrepareNoConfirm(self):
     self.ExpectGit([
@@ -408,7 +404,7 @@ class ScriptTest(unittest.TestCase):
     self.ExpectReadline(["n"])
     self.MakeStep().CommonPrepare()
     self.assertRaises(Exception, self.MakeStep().PrepareBranch)
-    self.assertEquals("some_branch", self.MakeStep().Restore("current_branch"))
+    self.assertEquals("some_branch", self._state["current_branch"])
 
   def testCommonPrepareDeleteBranchFailure(self):
     self.ExpectGit([
@@ -421,7 +417,7 @@ class ScriptTest(unittest.TestCase):
     self.ExpectReadline(["Y"])
     self.MakeStep().CommonPrepare()
     self.assertRaises(Exception, self.MakeStep().PrepareBranch)
-    self.assertEquals("some_branch", self.MakeStep().Restore("current_branch"))
+    self.assertEquals("some_branch", self._state["current_branch"])
 
   def testInitialEnvironmentChecks(self):
     TEST_CONFIG[DOT_GIT_LOCATION] = self.MakeEmptyTempFile()
@@ -432,14 +428,10 @@ class ScriptTest(unittest.TestCase):
     TEST_CONFIG[VERSION_FILE] = self.MakeTempVersionFile()
     step = self.MakeStep()
     step.ReadAndPersistVersion()
-    self.assertEquals("3", self.MakeStep().Restore("major"))
-    self.assertEquals("22", self.MakeStep().Restore("minor"))
-    self.assertEquals("5", self.MakeStep().Restore("build"))
-    self.assertEquals("0", self.MakeStep().Restore("patch"))
-    self.assertEquals("3", step._state["major"])
-    self.assertEquals("22", step._state["minor"])
-    self.assertEquals("5", step._state["build"])
-    self.assertEquals("0", step._state["patch"])
+    self.assertEquals("3", step["major"])
+    self.assertEquals("22", step["minor"])
+    self.assertEquals("5", step["build"])
+    self.assertEquals("0", step["patch"])
 
   def testRegex(self):
     self.assertEqual("(issue 321)",
@@ -490,7 +482,7 @@ class ScriptTest(unittest.TestCase):
        "Title\n\nBUG=456\nLOG=N\n\n"],
     ])
 
-    self.MakeStep().Persist("last_push", "1234")
+    self._state["last_push"] = "1234"
     self.MakeStep(PrepareChangeLog).Run()
 
     actual_cl = FileToText(TEST_CONFIG[CHANGELOG_ENTRY_FILE])
@@ -522,10 +514,10 @@ class ScriptTest(unittest.TestCase):
 #"""
 
     self.assertEquals(expected_cl, actual_cl)
-    self.assertEquals("3", self.MakeStep().Restore("major"))
-    self.assertEquals("22", self.MakeStep().Restore("minor"))
-    self.assertEquals("5", self.MakeStep().Restore("build"))
-    self.assertEquals("0", self.MakeStep().Restore("patch"))
+    self.assertEquals("3", self._state["major"])
+    self.assertEquals("22", self._state["minor"])
+    self.assertEquals("5", self._state["build"])
+    self.assertEquals("0", self._state["patch"])
 
   def testEditChangeLog(self):
     TEST_CONFIG[CHANGELOG_ENTRY_FILE] = self.MakeEmptyTempFile()
@@ -545,7 +537,7 @@ class ScriptTest(unittest.TestCase):
 
   def testIncrementVersion(self):
     TEST_CONFIG[VERSION_FILE] = self.MakeTempVersionFile()
-    self.MakeStep().Persist("build", "5")
+    self._state["build"] = "5"
 
     self.ExpectReadline([
       "Y",  # Increment build number.
@@ -553,10 +545,10 @@ class ScriptTest(unittest.TestCase):
 
     self.MakeStep(IncrementVersion).Run()
 
-    self.assertEquals("3", self.MakeStep().Restore("new_major"))
-    self.assertEquals("22", self.MakeStep().Restore("new_minor"))
-    self.assertEquals("6", self.MakeStep().Restore("new_build"))
-    self.assertEquals("0", self.MakeStep().Restore("new_patch"))
+    self.assertEquals("3", self._state["new_major"])
+    self.assertEquals("22", self._state["new_minor"])
+    self.assertEquals("6", self._state["new_build"])
+    self.assertEquals("0", self._state["new_patch"])
 
   def testLastChangeLogEntries(self):
     TEST_CONFIG[CHANGELOG_FILE] = self.MakeEmptyTempFile()
@@ -584,8 +576,8 @@ class ScriptTest(unittest.TestCase):
       ["svn find-rev hash1", "123455\n"],
     ])
 
-    self.MakeStep().Persist("prepare_commit_hash", "hash1")
-    self.MakeStep().Persist("date", "1999-11-11")
+    self._state["prepare_commit_hash"] = "hash1"
+    self._state["date"] = "1999-11-11"
 
     self.MakeStep(SquashCommits).Run()
     self.assertEquals(FileToText(TEST_CONFIG[COMMITMSG_FILE]), expected_msg)
@@ -810,8 +802,11 @@ Performance and stability improvements on all platforms.""", commit)
     auto_roll.RunAutoRoll(TEST_CONFIG, AutoRollOptions(
         MakeOptions(status_password=status_password)), self)
 
-    self.assertEquals("100", self.MakeStep().Restore("lkgr"))
-    self.assertEquals("100", self.MakeStep().Restore("latest"))
+    state = json.loads(FileToText("%s-state.json"
+                                  % TEST_CONFIG[PERSISTFILE_BASENAME]))
+
+    self.assertEquals("100", state["lkgr"])
+    self.assertEquals("100", state["latest"])
 
   def testAutoRollStoppedBySettings(self):
     TEST_CONFIG[DOT_GIT_LOCATION] = self.MakeEmptyTempFile()
@@ -906,6 +901,10 @@ LOG=N
       ["svn find-rev hash3 svn/bleeding_edge", "56789"],
       ["log -1 --format=%s hash3", "Title3"],
       ["svn find-rev \"r12345\" svn/bleeding_edge", "hash4"],
+      # Simulate svn being down which stops the script.
+      ["svn find-rev \"r23456\" svn/bleeding_edge", None],
+      # Restart script in the failing step.
+      ["svn find-rev \"r12345\" svn/bleeding_edge", "hash4"],
       ["svn find-rev \"r23456\" svn/bleeding_edge", "hash2"],
       ["svn find-rev \"r34567\" svn/bleeding_edge", "hash3"],
       ["svn find-rev \"r45678\" svn/bleeding_edge", "hash1"],
@@ -964,6 +963,15 @@ LOG=N
     # ports of r12345. r56789 is the MIPS port of r34567.
     args = ["trunk", "12345", "23456", "34567"]
     self.assertTrue(merge_to_branch.ProcessOptions(options, args))
+
+    # The first run of the script stops because of the svn being down.
+    self.assertRaises(Exception,
+        lambda: RunMergeToBranch(TEST_CONFIG,
+                                 MergeToBranchOptions(options, args),
+                                 self))
+
+    # Test that state recovery after restarting the script works.
+    options.s = 3
     RunMergeToBranch(TEST_CONFIG, MergeToBranchOptions(options, args), self)