diff -r 000000000000 -r 4f2f89ce4247 WebKitTools/Scripts/webkitpy/tool/steps/preparechangelog.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKitTools/Scripts/webkitpy/tool/steps/preparechangelog.py	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,78 @@
+# Copyright (C) 2010 Google Inc. 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 disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import os
+
+from webkitpy.common.checkout.changelog import ChangeLog
+from webkitpy.common.system.executive import ScriptError
+from webkitpy.tool.steps.abstractstep import AbstractStep
+from webkitpy.tool.steps.options import Options
+from webkitpy.common.system.deprecated_logging import error
+
+
+class PrepareChangeLog(AbstractStep):
+    @classmethod
+    def options(cls):
+        return AbstractStep.options() + [
+            Options.port,
+            Options.quiet,
+            Options.email,
+            Options.git_commit,
+        ]
+
+    def _ensure_bug_url(self, state):
+        if not state.get("bug_id"):
+            return
+        bug_id = state.get("bug_id")
+        changelogs = self.cached_lookup(state, "changelogs")
+        for changelog_path in changelogs:
+            changelog = ChangeLog(changelog_path)
+            if not changelog.latest_entry().bug_id():
+                changelog.set_short_description_and_bug_url(
+                    self.cached_lookup(state, "bug_title"),
+                    self._tool.bugs.bug_url_for_bug_id(bug_id))
+
+    def run(self, state):
+        if self.cached_lookup(state, "changelogs"):
+            self._ensure_bug_url(state)
+            return
+        os.chdir(self._tool.scm().checkout_root)
+        args = [self.port().script_path("prepare-ChangeLog")]
+        if state.get("bug_id"):
+            args.append("--bug=%s" % state["bug_id"])
+        if self._options.email:
+            args.append("--email=%s" % self._options.email)
+
+        if self._tool.scm().supports_local_commits():
+            args.append("--merge-base=%s" % self._tool.scm().merge_base(self._options.git_commit))
+
+        try:
+            self._tool.executive.run_and_throw_if_fail(args, self._options.quiet)
+        except ScriptError, e:
+            error("Unable to prepare ChangeLogs.")
+        state["diff"] = None # We've changed the diff