[tools] backport_node.py increments V8 version in target.

tools/release/backport_node.py

 #!/usr/bin/env python
 # Copyright 2017 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Use this script to cherry-pick a V8 commit to backport to a Node.js checkout.
 
 Requirements:
   - Node.js checkout to backport to.
   - V8 checkout that contains the commit to cherry-pick.
 
 Usage:
   $ backport_node.py <path_to_v8> <path_to_node> <commit-hash>
 
   This will apply the commit to <path_to_node>/deps/v8 and create a commit in
-  the Node.js checkout and copy over the original commit message.
+  the Node.js checkout, increment patch level, and copy over the original
+  commit message.
 
 Optional flags:
   --no-review  Run `gclient sync` on the V8 checkout before updating.
 """
 
 import argparse
 import os
 import subprocess
+import re
 import sys
 
+from common_includes import *
+
 TARGET_SUBDIR = os.path.join("deps", "v8")
+VERSION_FILE = os.path.join("include", "v8-version.h")
+VERSION_PATTERN = r'(?<=#define V8_PATCH_LEVEL )\d+'
+
+def Clean(options):
+  print ">> Cleaning target directory."
+  subprocess.check_call(["git", "clean", "-fd"],
+                        cwd = os.path.join(options.node_path, TARGET_SUBDIR))
 
 def CherryPick(options):
   print ">> Apply patch."
   patch = subprocess.Popen(["git", "diff-tree", "-p", options.commit],
                            stdout=subprocess.PIPE, cwd=options.v8_path)
   patch.wait()
   try:
     subprocess.check_output(["git", "apply", "-3", "--directory=%s" % TARGET_SUBDIR],
                             stdin=patch.stdout, cwd=options.node_path)
   except:
     print ">> In another shell, please resolve patch conflicts"
     print ">> and `git add` affected files."
     print ">> Finally continue by entering RESOLVED."
     while raw_input("[RESOLVED]") != "RESOLVED":
       print ">> You need to type RESOLVED"
 
+def UpdateVersion(options):
+  print ">> Increment patch level."
+  version_file = os.path.join(options.node_path, TARGET_SUBDIR, VERSION_FILE)
+  text = FileToText(version_file)
+  def increment(match):
+    patch = int(match.group(0))
+    return str(patch + 1)
+  text = re.sub(VERSION_PATTERN, increment, text, flags=re.MULTILINE)
+  TextToFile(text, version_file)
+
 def CreateCommit(options):
   print ">> Creating commit."
   # Find short hash from source.
   shorthash = subprocess.check_output(
       ["git", "rev-parse", "--short", options.commit],
       cwd=options.v8_path).strip()
 
   # Commit message
   title = "deps: backport %s from upstream V8"  % shorthash
   body = subprocess.check_output(
@@ skipping 22 matching lines @@
                       help="Skip editing commit message")
   options = parser.parse_args(args)
   options.v8_path = os.path.abspath(options.v8_path)
   assert os.path.isdir(options.v8_path)
   options.node_path = os.path.abspath(options.node_path)
   assert os.path.isdir(options.node_path)
   return options
 
 def Main(args):
   options = ParseOptions(args)
+  Clean(options)
   try:
     CherryPick(options)
+    UpdateVersion(options)
     CreateCommit(options)
   except:
     print ">> Failed. Resetting."
     subprocess.check_output(["git", "reset", "--hard"], cwd=options.node_path)
     raise
 
 if __name__ == "__main__":
   Main(sys.argv[1:])