Add tag write access to merge script.

tools/push-to-trunk/common_includes.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 278 matching lines @@
   def Land(self):
     raise NotImplementedError()
 
   def CLLand(self):
     raise NotImplementedError()
 
   # TODO(machenbach): There is some svn knowledge in this interface. In svn,
   # tag and commit are different remote commands, while in git we would commit
   # and tag locally and then push/land in one unique step.
   def Tag(self, tag, remote):
+    """Sets a tag for the current commit.
+
+    Assumptions: The commit already landed and the commit message is unique.
+    """
     raise NotImplementedError()
 
 
 class GitSvnInterface(VCInterface):
   def Pull(self):
     self.step.GitSVNRebase()
 
   def Fetch(self):
     self.step.GitSVNFetch()
 
@@ skipping 32 matching lines @@
 
   def CLLand(self):
     self.step.GitDCommit()
 
   def Tag(self, tag, remote):
     self.step.GitSVNFetch()
     self.step.Git("rebase %s" % remote)
     self.step.GitSVNTag(tag)
 
 
-class GitReadOnlyMixin(VCInterface):
+class GitTagsOnlyMixin(VCInterface):
   def Pull(self):
     self.step.GitPull()
 
   def Fetch(self):
     self.step.Git("fetch")
 
   def GetTags(self):
      return self.step.Git("tag").strip().splitlines()
 
   def GetBranches(self):
     # Get relevant remote branches, e.g. "origin/branch-heads/3.25".
     branches = filter(
         lambda s: re.match(r"^origin/branch\-heads/\d+\.\d+$", s),
         self.step.GitRemotes())
     # Remove 'origin/branch-heads/' prefix.
     return map(lambda s: s[20:], branches)
 
   def RemoteMasterBranch(self):
     return "origin/master"
 
   def RemoteCandidateBranch(self):
     return "origin/candidates"
 
   def RemoteBranch(self, name):
     if name in ["candidates", "master"]:
       return "origin/%s" % name
     return "origin/branch-heads/%s" % name
 
+  def Tag(self, tag, remote):
+    # Title of the current commit (the local title and the title for committing
+    # is the same in all merge and push scripts).
+    title = self.step.GitLog(n=1, format="%s")
 
-class GitReadSvnWriteInterface(GitReadOnlyMixin, GitSvnInterface):
+    # Wait for the commit to appear. Assumes unique commit message titles (this
+    # is the case for all automated merge and push commits - also no title is
+    # the prefix of another title).
+    commit = None
+    for wait_interval in [3, 5, 10, 30]:

[tandrii(chromium), 2014/10/02 17:36:06]

not sure 48 seconds is enough, you probably know better anyways.

[Michael Achenbach, 2014/10/07 10:10:50]

Bumped it a little.

+      self.step.Git("fetch")
+      commit = self.step.GitLog(n=1, format="%H", grep=title, branch=remote)
+      if commit:

[tandrii(chromium), 2014/10/02 17:36:06]

Naturally, i'm not sure about assumption above the loop. So, I'd check the title
for equality here anyways.

[Michael Achenbach, 2014/10/07 10:10:50]

I don't need the assumption if I add the commit message/title to the api (which
I did now).

+        break
+      print("The commit has not replicated to git. Waiting for %s seconds." %
+            wait_interval)
+      self.step._side_effect_handler.Sleep(wait_interval)
+
+    if not commit:

[tandrii(chromium), 2014/10/02 17:36:06]

or just

else:

[Michael Achenbach, 2014/10/07 10:10:50]

Odd construct - but I love shorter code :)

+      self.step.Die("Couldn't determine commit for setting the tag. Maybe the "
+                    "git updater is lagging behind?")
+
+    self.step.Git("tag %s %s" % (tag, commit))
+    self.step.Git("push origin %s" % tag)
+
+
+class GitReadSvnWriteInterface(GitTagsOnlyMixin, GitSvnInterface):
   pass
 
 
 VC_INTERFACES = {
   "git_svn": GitSvnInterface,
   "git_read_svn_write": GitReadSvnWriteInterface,
 }
 
 
 class Step(GitRecipesMixin):
@@ skipping 446 matching lines @@
     for (number, step_class) in enumerate(step_classes):
       steps.append(MakeStep(step_class, number, self._state, self._config,
                             options, self._side_effect_handler))
     for step in steps[options.step:]:
       if step.Run():
         return 0
     return 0
 
   def Run(self, args=None):
     return self.RunSteps(self._Steps(), args)