Setup git-svn and handle detached HEAD state in auto-rebaseline script.

Tools/Scripts/webkitpy/tool/commands/rebaseline.py

 # 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
@@ skipping 785 matching lines @@
 
     def execute(self, options, args, tool):
         if tool.scm().executable_name == "svn":
             _log.error("Auto rebaseline only works with a git checkout.")
             return
 
         if tool.scm().has_working_directory_changes():
             _log.error("Cannot proceed with working directory changes. Clean working directory first.")
             return
 
+        # Setup git-svn for dcommit.
+        tool.executive.run_command(['git', 'auto-svn'])

[Dirk Pranke, 2015/06/12 19:51:30]

I wonder if there's much of a cost to running this every time, and if we should
only run this if svn isn't set up.

[joelo, 2015/06/17 18:37:37]

Good point, done.

+
         revision_data = self.bot_revision_data()
         if not revision_data:
             return
 
         min_revision = int(min([item["revision"] for item in revision_data]))
         tests, revision, author, bugs, has_any_needs_rebaseline_lines = self.tests_to_rebaseline(tool, min_revision, print_revisions=options.verbose)
 
         if options.verbose:
             _log.info("Min revision across all bots is %s." % min_revision)
             for item in revision_data:
                 _log.info("%s: r%s" % (item["builder"], item["revision"]))
 
         if not tests:
             _log.debug('No tests to rebaseline.')
             return
 
         if self.tree_status() == 'closed':
             _log.info('Cannot proceed. Tree is closed.')
             return
 
         _log.info('Rebaselining %s for r%s by %s.' % (list(tests), revision, author))
 
         test_prefix_list, lines_to_remove = self.get_test_prefix_list(tests)
 
         did_finish = False
         try:
-            old_branch_name = tool.scm().current_branch()
+            old_branch_name = tool.executive.run_command(["git", "rev-parse", "--symbolic-full-name", "HEAD"])
+            if old_branch_name == "HEAD":
+                # If HEAD is detached use commit SHA instead.
+                old_branch_name = tool.executive.run_command(["git", "rev-parse", "HEAD"])
             tool.scm().delete_branch(self.AUTO_REBASELINE_BRANCH_NAME)
             tool.scm().create_clean_branch(self.AUTO_REBASELINE_BRANCH_NAME)
 
             # If the tests are passing everywhere, then this list will be empty. We don't need
             # to rebaseline, but we'll still need to update TestExpectations.
             if test_prefix_list:
                 self._rebaseline(options, test_prefix_list)
 
             tool.scm().commit_locally_with_message(self.commit_message(author, revision, bugs))
 
@@ skipping 91 matching lines @@
             self._tool.scm().checkout_branch(old_branch_name)
         else:
             self._log_queue.put(self.QUIT_LOG)
         log_thread.join()
 
     def execute(self, options, args, tool):
         self._verbose = options.verbose
         while True:
             self._do_one_rebaseline()
             time.sleep(self.SLEEP_TIME_IN_SECONDS)