[Release] Update merge script to leverage auto-tag bot

tools/release/merge_to_branch.py

Index: tools/release/merge_to_branch.py
diff --git a/tools/release/merge_to_branch.py b/tools/release/merge_to_branch.py
index 699fe1b3c66dbc5fc67970616eb811136ecad844..ead4ce0f7982cd170df1831bec2ef7122348d52a 100755
--- a/tools/release/merge_to_branch.py
+++ b/tools/release/merge_to_branch.py
@@ -47,10 +47,8 @@ class Preparation(Step):
     open(self.Config("ALREADY_MERGING_SENTINEL_FILE"), "a").close()
 
     self.InitialEnvironmentChecks(self.default_cwd)
-    if self._options.branch:
-      self["merge_to_branch"] = self._options.branch
-    else:  # pragma: no cover
-      self.Die("Please specify a branch to merge to")
+
+    self["merge_to_branch"] = self._options.branch
 
     self.CommonPrepare()
     self.PrepareBranch()
@@ -74,7 +72,7 @@ class SearchArchitecturePorts(Step):
     for revision in self["full_revision_list"]:
       # Search for commits which matches the "Port XXX" pattern.
       git_hashes = self.GitLog(reverse=True, format="%H",
-                               grep="Port %s" % revision,
+                               grep="^[Pp]ort %s" % revision,
                                branch=self.vc.RemoteMasterBranch())
       for git_hash in git_hashes.splitlines():
         revision_title = self.GitLog(n=1, format="%s", git_hash=git_hash)
@@ -99,6 +97,12 @@ class SearchArchitecturePorts(Step):
 class CreateCommitMessage(Step):
   MESSAGE = "Create commit message."
 
+  def _create_commit_description(self, commit_hash):
+    patch_merge_desc = self.GitLog(n=1, format="%s", git_hash=commit_hash)

[Michael Achenbach, 2016/07/21 13:56:37]

Is this done twice? E.g. below?

[Michael Hablich, 2016/07/21 14:27:33]

Done.

+    description = "Merged: " + patch_merge_desc + "\n"
+    description = description + "Revision: " + commit_hash + "\n\n"

[Michael Achenbach, 2016/07/21 13:56:37]

nit: description += ...

or to avoid multiple string buffers use % like

return "Merged: %s\nRevision: %s\n\n" % (patch_merge_desc, commit_hash)

[Michael Hablich, 2016/07/21 14:27:32]

Done.

+    return description
+
   def RunStep(self):
 
     # Stringify: ["abcde", "12345"] -> "abcde, 12345"
@@ -107,17 +111,18 @@ class CreateCommitMessage(Step):
     if not self["revision_list"]:  # pragma: no cover
       self.Die("Revision list is empty.")
 
-    action_text = "Merged %s"
+    msg_pieces = []
 
-    # The commit message title is added below after the version is specified.
-    msg_pieces = [
-      "\n".join(action_text % s for s in self["full_revision_list"]),
-    ]
-    msg_pieces.append("\n\n")
+    if len(self["full_revision_list"]) > 1:
+      self["commit_title"] = "Merged: Squashed multiple commits."
+    else:
+      commit_hash = self["full_revision_list"][0]
+      patch_merge_desc = self.GitLog(n=1, format="%s", git_hash=commit_hash)
+      title = "Merged: " + patch_merge_desc

[Michael Achenbach, 2016/07/21 13:56:37]

nit: inline title or also patch_merge_desc

[Michael Hablich, 2016/07/21 14:27:32]

Done.

+      self["commit_title"] = title
 
     for commit_hash in self["full_revision_list"]:
-      patch_merge_desc = self.GitLog(n=1, format="%s", git_hash=commit_hash)
-      msg_pieces.append("%s\n\n" % patch_merge_desc)
+      msg_pieces.append(self._create_commit_description(commit_hash))

[Michael Achenbach, 2016/07/21 13:56:37]

Don't we get a double title here?

[Michael Hablich, 2016/07/21 14:27:33]

Done.

 
     bugs = []
     for commit_hash in self["full_revision_list"]:
@@ -144,49 +149,28 @@ class ApplyPatches(Step):
     if self._options.patch:
       self.ApplyPatch(self._options.patch)
 
-
-class PrepareVersion(Step):
-  MESSAGE = "Prepare version file."
-
-  def RunStep(self):
-    # This is used to calculate the patch level increment.
-    self.ReadAndPersistVersion()
-
-
-class IncrementVersion(Step):
-  MESSAGE = "Increment version number."
-
-  def RunStep(self):
-    new_patch = str(int(self["patch"]) + 1)
-    if self.Confirm("Automatically increment V8_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 "
-                    "EDITOR.)" % VERSION_FILE):
-      text = FileToText(os.path.join(self.default_cwd, VERSION_FILE))
-      text = MSub(r"(?<=#define V8_PATCH_LEVEL)(?P<space>\s+)\d*$",
-                  r"\g<space>%s" % new_patch,
-                  text)
-      TextToFile(text, os.path.join(self.default_cwd, VERSION_FILE))
-    else:
-      self.Editor(os.path.join(self.default_cwd, VERSION_FILE))
-    self.ReadAndPersistVersion("new_")
-    self["version"] = "%s.%s.%s.%s" % (self["new_major"],
-                                       self["new_minor"],
-                                       self["new_build"],
-                                       self["new_patch"])
-
-
 class CommitLocal(Step):
   MESSAGE = "Commit to local branch."
 
   def RunStep(self):
     # Add a commit message title.
-    self["commit_title"] = "Version %s (cherry-pick)" % self["version"]
     self["new_commit_msg"] = "%s\n\n%s" % (self["commit_title"],
                                            self["new_commit_msg"])
     TextToFile(self["new_commit_msg"], self.Config("COMMITMSG_FILE"))
     self.GitCommit(file_name=self.Config("COMMITMSG_FILE"))
 
+class AddInformationalComment(Step):
+  MESSAGE = 'Show additional information.'
+
+  def RunStep(self):
+    message = ("Please note that you are using a new "

[Michael Achenbach, 2016/07/21 13:56:38]

Suggestion for making this readable to lazy devs: Remove first and last
sentence. E.g.:

NOTE: This script will no longer update include/v8-version.h and create a tag.
This is done automatically by the autotag bot. See 'merge_to_branch.py --help'
for more details.

[Michael Hablich, 2016/07/21 14:27:33]

Done.

+     "version of the script merge_to_branch.py. "
+     "This script will no longer automatically update include/v8-version.h "
+     "and create a tag. This is ok, the trustworthy autotag bot will "
+     "take care of that. The old script is still available in "
+     "tools/release/roll_merge.py.")
+
+    self.GitCLAddComment(message)
 
 class CommitRepository(Step):
   MESSAGE = "Commit to the repository."
@@ -197,24 +181,12 @@ class CommitRepository(Step):
     self.GitPresubmit()
     self.vc.CLLand()
 
-
-class TagRevision(Step):
-  MESSAGE = "Create the tag."
-
-  def RunStep(self):
-    print "Creating tag %s" % self["version"]
-    self.vc.Tag(self["version"],
-                self.vc.RemoteBranch(self["merge_to_branch"]),
-                self["commit_title"])
-
-
 class CleanUp(Step):
   MESSAGE = "Cleanup."
 
   def RunStep(self):
     self.CommonCleanup()
     print "*** SUMMARY ***"
-    print "version: %s" % self["version"]
     print "branch: %s" % self["merge_to_branch"]
     if self["revision_list"]:
       print "patches: %s" % self["revision_list"]
@@ -223,7 +195,7 @@ class CleanUp(Step):
 class MergeToBranch(ScriptsBase):
   def _Description(self):
     return ("Performs the necessary steps to merge revisions from "

[Michael Achenbach, 2016/07/21 13:56:38]

Suggestion: Add more details here including all relevant information about
version file, auto tagging, etc.

[Michael Hablich, 2016/07/21 14:27:33]

Done.

-            "master to other branches, including candidates.")
+            "master to release branches like 4.5.")
 
   def _PrepareOptions(self, parser):
     group = parser.add_mutually_exclusive_group(required=True)
@@ -250,6 +222,12 @@ class MergeToBranch(ScriptsBase):
     # CC ulan to make sure that fixes are merged to Google3.
     options.cc = "ulan@chromium.org"
 
+    # This script only supports official release branches, not roll branches

[Michael Achenbach, 2016/07/21 13:56:37]

nit: Comment is redundant to print message. Rather drop it.

[Michael Hablich, 2016/07/21 14:27:33]

Done.

+    if len(options.branch.split('.')) > 2:
+      print ("This script does not support merging to roll branches (yet). "

[Michael Achenbach, 2016/07/21 13:56:37]

nit: remove 'yet' to avoid embarrassment when it's still the same in two years
:).

[Michael Hablich, 2016/07/21 14:27:32]

Done.

+            "Please use tools/release/roll_merge.py for this use case.")

[Michael Achenbach, 2016/07/21 13:56:37]

nit indentation - one space more...

[Michael Hablich, 2016/07/21 14:27:33]

Done.

+      return False
+
     # Make sure to use git hashes in the new workflows.
     for revision in options.revisions:
       if (IsSvnNumber(revision) or
@@ -276,12 +254,10 @@ class MergeToBranch(ScriptsBase):
       SearchArchitecturePorts,
       CreateCommitMessage,
       ApplyPatches,
-      PrepareVersion,
-      IncrementVersion,
       CommitLocal,
       UploadStep,
+      AddInformationalComment,
       CommitRepository,
-      TagRevision,
       CleanUp,
     ]